Emerson 2468Cb Users Manual
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Hydrastep 2468CB and 2468CD
Hydrastep 2468
Operating Manual
24685034, Rev. AE
June 2011
www.mobrey.com
Electronic Gauging System
(Dual Power Supply Version)
CATEGORY SYMPTOM POSSIBLE CAUSES (See Note 1) SOLUTION (See Note 2)
PSU (AC)
PSU (DC)
Hydrastep system does not power-up.
Hydrastep system does not power-up.
Wrong voltage setting.
Incorrect supply.
Blown fuse.
Incorrect cable termination.
Incorrect supply.
Blown fuse.
Incorrect cable termination.
Refer to Part 1, Section 2.4.2.4.
Refer to Part 1, Section 2.4.2.4.
MAIN DISPLAY Chequered / intermittent display.
No display.
Yellow LED illuminated.
Incorrect configuration. Refer to Part 1, Section 2.5.2.
Refer to Part 1, Section 2.5.2.1.
Refer to Part 1, Section 2.5.2.2.
REMOTE DISPLAY Chequered / intermittent display.
No display.
Yellow LED illuminated.
Incorrect configuration.
Incorrect interface cable connection.
Check Main Display, as above.
See Part 1, Section 4.2 (Relevant display).
Check cable connections. See Part 1, Section4.4.
ELECTRODE ALARM
ERROR Flashing Red (steam) and Green (water)
LED’s with Yellow alarm LED illuminated. Electrode contamination
Incorrect column installation reducing
condensate flow.
Water conductivity is too high.
Refer to Part 2, Section 3.
Refer to Part 2, Section 2.3.
Refer to Part 1, Section 2.5.1.3.
Refer to Part 1, Section 2.5.1.4.
WATER/STEAM
SWITCHING
THRESHOLD
Water above steam (green above red) with
yellow LED illuminated Threshold not matched to application.
Electrode contamination.
Refer to Part 1, Section 2.5.2.3.
Refer to Part 2, Section 3.
Note 1: Further detailed information can be found in Fault finding Part 1, Sections 2.6 and 4.5.
Note 2: References are to Operating Manuals 24685033 (for 2468CA and 2468CC models) and 24685034 (for 2468CB and 2468CD models).
HYDRASTEP START-UP
It is possible that some of these conditions will be seen on a new Hydrastep installation.
** This does not mean that the equipment you have purchased is faulty **
Due to the nature of the areas that Hydrastep is normally installed, various conditions can occur that make the instrument operate in an unusual manner.
It would be easy to think you have installed defective equipment, but it is very unlikely that this is the case.
Great care must be taken when installing a Hydrastep system so that these problems are less likely to be seen; firstly, please take the time to ensure that the various people involved
in the fitting of the components have been shown and have read the handbook, which is supplied with all new Hydrastep systems.
This, along with the wiring diagrams (also supplied), should make for a trouble free installation.
1. Please read and understand Part 2 of the handbook, which explains the pressure side of the equipment.
2. Ensure wiring is of the correct type and that the wiring diagram supplied has been followed.
3. Hydrastep relies on a ‘path back to earth’. Please make sure that all earth points are made and are of a good standard.
4. Great care must be taken with the mounting of the water column; the columns must be vertical; angles stated in the manual should be as close as possible, as this ensures
condensate flow back into the column.
5. Lagging of the pipe work must be as stated; ** The last 0.5 m of the (top) steam leg MUST NOT be insulated as this will inhibit condensate flow into the column; this will cause a
flickering display.**
6. Please be aware of your water quality as some adjustments to the Hydrastep may be required if it has a high conductivity. Please let us know when placing your order if your
water conductivity is high. We can modify the units up to 1600Us/cm.
7. Units will not leave the factory configured for customer orders unless requested. If you wish it to be configured, please request it on your order and it will then be done. Options
include mains voltage to be used, trip points (if relay cards are to be fitted), number of electrodes to be used and remote display option (if ordered). These points are not pre-set
as standard as the factory do not know your requirement unless stated on your order.
8. Care should be taken to make sure that a new set of electrodes have been fitted after the first acid wash of the system. The electrodes may well have been damaged during this
process and a new set should go in before you run the system up for the first time.
9. The most common problem seen with Hydrastep systems is a flickering pattern on the display while the boiler is being brought up to operating pressure and temperature. This is
not a fault and is caused by a few conditions specific to power stations:
(a) If a boiler is new or has seen a large amount re-work, it may well get a coating of magnetite inside of it, when it is first started up. This creates a small DC voltage that is
picked up on the electrodes and shows its self as a flickering in the bottom few electrodes. When the system is brought up to its normal working condition’s this will settle but
can take a couple of days to do so.
(b) It is possible that the top electrodes may have a wet coating on them until these working conditions are met; again, if left to settle, this will work at normal working conditions.
(c) Should the plant generate a higher than normal amount of DC noise, we can supply a blocking cap that is built into a PCB that will stop this problem.
If you are in any doubt about what you are doing, contact Customer Support of Mobrey Limited on +44 (0) 1753 756600 for guidance
Mobrey Customer Support
(April 2005)
About this manual
This manual describes the Hydrastep 2468CB and 2468CD Electronic Gauging Systems along with the
recommended options. Except where stated otherwise, the information contained in this manual can be assumed
to apply to either system.
This manual is divided into three parts; the first covers the electrical/electronic system; the second describes the
pressure parts; the third is for coverage of all other aspects.
Part 1 – Electrical/Electronic System
Chapter 1 introduces the Hydrastep 2468 Electronic Gauging System and its operating principles.
Chapter 2 covers the installation, configuration and fault analysis procedures.
Chapter 3 covers the installation, configuration and fault analysis procedures for the Relay Output Board (Chapter 3a),
the Delay Relay Output Board (Chapter 3b) and the Opto-isolated Output Board (Chapter 3c).
Chapter 4 covers the installation, configuration and fault analysis procedures for all versions of the Remote
Display Unit.
Part 2 – Pressure Parts
Chapter 1 is a general introduction to the Hydrastep system of water level determination.
Chapter 2 describes the water column and its components – the preparation, installation of the water column on to
the boiler, acid and steam purging of the boiler system and the fitting of the electrode sensors.
Chapter 3 details the fault repair procedures carried out on the system pressure parts and their commissioning.
Chapter 4 provides a general description of the pressure parts used in the Hydrastep systems.
Chapter 5 details the Pressure Parts specifications.
Caution:
For installation under the Pressure Equipment Directive (PED) 97/23/EC, refer to safety instruction
manual 24688006/SI.
Caution:
For installation under ATEX directive 94/09/EC, refer to safety instruction manual 24685033/SI.
Part 3 – Appendix
Appendix A contains a CSA certified connection drawing and associated notes.
Caution:
For installation in potentially explosive atmospheres in Canada and USA, refer to control drawing
24685037 in Part 3.
SYMBOLS USED IN THIS MANUAL AND ON THE UNIT
Symbol Meaning
Direct Current
Alternating Current
Earth (ground) terminal
Protective conductor terminal
Caution (refer to accompanying documents)
24685034 Pt.1-1
Part 1
Hydrastep 2468CB & 2468CD
Electronic Gauging System
Pt.1-2 24685034
24685034 Pt.1-3
DANGEROUS VOLTAGES ARE PRESENT IN
THIS EQUIPMENT. ANY WARNING NOTICES
OR PROCEDURES CONTAINED IN THIS
MANUAL OR ON THE EQUIPMENT SHOULD BE
STRICTLY OBSERVED TO MAINTAIN SAFETY.
THE USE OF THIS EQUIPMENT IN A MANNER
NOT SPECIFIED IN THIS MANUAL MAY IMPAIR
THE PROTECTION PROVIDED BY THIS
EQUIPMENT. GREAT CARE SHOULD BE
EXERCISED WHEN SERVICING THIS
EQUIPMENT.
TO ENSURE COMPLIANCE WITH THE EMC
DIRECTIVE (WHERE APPLICABLE) THE
INSTRUCTIONS ON CABLE SCREENING,
ROUTING AND TERMINATION GIVEN IN THIS
MANUAL MUST BE FOLLOWED.
Pt.1-4 24685034
24685034 Pt.1-5
Part 1
Contents
Chapter 1 Introduction to the Hydrastep 2468 Electronic
Gauging System
Chapter 2 2468CB & 2468CD Dual Power Supply Version
Chapter 3a 2468 - Relay Output Board Option
Chapter 3b Delay Relay Output Board Option
Chapter 3c 2468 Opto-isolated Output Board Option
Chapter 4 Remote Display Options 24683B C & D
Pt.1-6 24685034
Hydrastep 2468CB and 2468CD Manual Introduction to the Hydrastep 2468 Electronic Gauging System
24685034 1-1
1
Introduction to the Hydrastep 2468
Electronic Gauging System
Contents
Page No.
1.1 WATER LEVEL MEASUREMENT .......................................................... 3
1.2 HYDRASTEP 2468 ELECTRONIC GAUGING SYSTEM ....................... 5
1.2.1 INPUT BOARDS .................................................................................. 5
1.2.2 DISPLAY BOARDS .............................................................................. 5
1.2.3 SYSTEM FAULTS (2468CB OR 2468CD) ........................................... 6
1.3 SYSTEM OPTIONS ................................................................................. 6
1.3.1 OUTPUT BOARDS .............................................................................. 6
1.3.2 REMOTE DISPLAY UNITS .................................................................. 6
1.3.3 OPTION DETAILS ................................................................................ 6
1.4 HYDRASTEP 2468 UPGRADE PATHS AND AVAILABLE OPTIONS .. 7
Illustrations
Figure 1.1 - Front panel of the Hydrastep 2468 gauging system, with local display .......... 2
Figure 1.2 - Schematic of resistance measuring cell and electrodes ................................. 3
Figure 1.3 - Typical Hydrastep 2468 System Installation.................................................... 4
Tables
Table 1.1 - Upgrade paths and available options ............................................................... 7
Introduction to the Hydrastep 2468 Electronic Gauging System Hydrastep 2468CB and 2468CD Manual
1-2 24685034
0040
Figure 1.1 - Front panel of the Hydrastep 2468 gauging system
Hydrastep 2468CB and 2468CD Manual Introduction to the Hydrastep 2468 Electronic Gauging System
24685034 1-3
1.1 WATER LEVEL MEASUREMENT
The Hydrastep 2468 Electronic Gauging System is designed as an electronic alternative to
water level gauges on boilers, giving a more reliable and safer water level indication than
conventional visual gauges. It uses the significant difference in resistivities of water and
steam in temperatures up to 370C (698F) to determine the water level.
Figure 1.2 - Schematic of resistance measuring cell and electrodes
A vertical row of electrodes is installed in the water level column attached to boiler and
typically aligned so that half the electrodes are above and half below the normal water level
(see Figure 1.2). The resistance measurement is made between the insulated tip of each
electrode and the wall of the column.
The “cell constant” defining the actual resistance measured is determined by the length and
diameter of the electrode tip and the column bore. In practice, the cell constant is chosen so
that the resistance in water is less than 100k ohms and the steam resistance is greater than
10M ohms. Since the resistivities of water and steam are substantially different, the system
is simple and requires no setting up adjustments. It is not susceptible to power supply
variations, ambient temperature changes, etc., resulting in a highly reliable system.
A general overview showing how a typical Hydrastep 2468 System is installed is illustrated
in Figure 1.3.
Introduction to the Hydrastep 2468 Electronic Gauging System Hydrastep 2468CB and 2468CD Manual
1-4 24685034
Figure 1.3 - Typical Hydrastep 2468 System Installation
Hydrastep 2468CB and 2468CD Manual Introduction to the Hydrastep 2468 Electronic Gauging System
24685034 1-5
1.2 HYDRASTEP 2468 ELECTRONIC GAUGING SYSTEM
The Hydrastep 2468 is a sophisticated and flexible electronic gauging system. It is supplied
in two main versions:
A Single Power Supply System with Local Level Display
A Dual Power Supply System with Local Level Display
For both systems, the printed circuit boards are housed in the same enclosure, allowing
customers full capability to expand their system as and when conditions dictate.
Table 1.1 on page 1.7 is a summary of all upgrade paths and options for the Hydrastep 2468
system.
1.2.1 INPUT BOARDS
All versions of the Hydrastep 2468 unit contain one or two input boards. The input boards
mount on to the base plate in the enclosure. Each input board provides power supplies,
electrode drive, signal processing, fault analysis and an analogue output.
The input board can accept inputs from 8, 10, 12, 14 or 16 electrodes. When two input
boards are used (in a ‘dual power supply’ system) the electrodes are ‘interlaced’; that is, the
odd numbered electrodes are connected to one input board and the even numbered
electrodes are connected to the other. Full details of the wiring are covered in Chapter 2
under Installation.
Each input board also includes a current output circuit that provides an analogue
representation of the water level in the column. The analogue output can be configured to
give a current output in one of the following ranges:
0 to 20mA
4 to 20mA
20 to 0mA
20 to 4mA
1.2.2 DISPLAY BOARD
The display board is mounted on to the hinged lid of the unit and provides indication through
the viewing window on the enclosure. It also supplies configuration information to the input
board(s); that is, the number of electrodes connected to the unit and the required
water/steam switching threshold.
Figure 1.1 shows the local display with water level and system fault indication. Water level
is indicated by two columns of LEDs, one red to indicate steam and one green to indicate
water. The number of LEDs illuminated is dependent on the number of electrodes present
and a blanking panel is available to mask the LEDs not used. In addition to the system fault
indication is an opto-isolated system fault output. Switches are provided to allow the
number of electrodes to be selected (8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 or 32). Two
solder link pads are provided to select the water/steam switching threshold (0.6S/cm or
1.6S/cm).
Introduction to the Hydrastep 2468 Electronic Gauging System Hydrastep 2468CB and 2468CD Manual
1-6 24685034
1.2.3 SYSTEM FAULTS (2468CB OR 2468CD)
System fault indication, a yellow LED and an opto-isolated output, is provided for a ‘water
above steam’ condition, an electrode fault or wiring failure and the detection of an internal
fault. A further fault is indicated when the electrode number switch is incorrectly set. This
fault is indicated by a chequered display of red and green LEDs on the level display.
Faults and their remedies are covered in Chapter 2 under ‘Fault Analysis & Corrective
Action’.
1.3 SYSTEM OPTIONS
1.3.1 OUTPUT BOARDS
Each input board can accept one or two output boards that can be used for water level
signalling, alarm or trip functions. Each output board provides four relay outputs or four opto-
isolated outputs. The first output board is fitted directly on top of the input board using three
nylon pillars. A second output board (when required) can be fitted on top of the first output
board using the same type of fixture. The various output boards are described in Chapter 3.
1.3.2 REMOTE DISPLAY UNITS
Provision is made to drive Remote Display Units. The display board is capable of driving up
to 6 remote display units. Only one of these can be powered by the Hydrastep unit, any
additional remote displays must be locally powered.
A remote display unit ‘mimics’ the display on the Hydrastep 2468 and is as described in
Chapter 4.
1.3.3 OPTION DETAILS
1. Relay Board 24680504 has 4 fully configurable relay outputs Chapter 3a
2. Relay with Time Delay board 24680509 has 4 fully configurable relay outputs Chapter 3b
3. Opto-isolator board 24680505 has 4 fully configurable opto-isolated outputs Chapter 3c
4. Remote Display 24683B. Panel mounted DIN size 8 to 32 electrode display Chapter 4
5. Remote Display 24683C Panel mounted large LED 8 to 32 electrode display Chapter 4
6. Remote Display 24683D Wall mounted splash proof version of 24683C Chapter 4
Hydrastep 2468CB and 2468CD Manual Introduction to the Hydrastep 2468 Electronic Gauging System
24685034 1-7
1.4 HYDRASTEP 2468 UPGRADE PATHS AND AVAILABLE
OPTIONS
Table 1.1 describes the available versions of the Hydrastep 2468 Electronic Gauging System
and their possible options.
Existing System Available Options Comments
Description Part No.
2468 CA or
2468 CC
16 point EGS with
local display
Single power
supply.
Relay output board
Time delay relay
output board
Opto-isolated
output board
Remote display
unit
Input board
upgrade (ac)
Input board
upgrade (dc)
24680504C
24680509B
24680505A
24683B, C, or D
24680501C
24680516B
}
}
} Up to two boards (of any one
} type) can be fitted.
}
}
Up to 6 can be used
Provides an additional power
supply (ac mains source) and
16 point input circuit. Upgrades
2468CA to 2468CB.
Provides an additional power
supply (24V dc source) and 16
point input circuit. Upgrades
2468CC to 2468CD.
2468 CB or
2468 CD
32 point EGS with
local display
Dual power supply.
Relay output board
Time delay relay
output board
Opto-isolated
output board
Remote display
unit
24680504C
24680509B
24680505A
24683B, C, or D
}
}
} Up to four boards (of any one
} type) can be fitted.
}
}
Up to 6 can be used
Note: If required, a 24680501C board can be fitted to a 2468CC (or a 24680516B board
can be fitted to a 2468CA) to upgrade to a 2468CE. The 2468CE is a 32 point
Electronic Gauging System (EGS) with one ac mains source power supply and one
24Vdc source power supply.
Table 1.1 - Upgrade paths and available options
Introduction to the Hydrastep 2468 Electronic Gauging System Hydrastep 2468CB and 2468CD Manual
1-8 24685034
Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version
24685034 2-1
2
2468CB & 2468CD
Dual Power Supply Version
Contents
Page No.
2.1 INTRODUCTION ....................................................................................... 2-3
2.2 ELECTRODE CABLING SYSTEM ........................................................... 2-3
2.3 ELECTRONIC ENCLOSURE .................................................................... 2-3
2.3.1 INPUT BOARD (PCB 24680501 AND PCB 24680516) ......................... 2-5
2.3.1.1 Analogue Output Drive Capability ........................................... 2-5
2.3.2 REMOTE DISPLAY DRIVE CAPABILITY .............................................. 2-5
2.3.3 DISPLAY BOARD (PCB 24680515)....................................................... 2-6
2.3.3.1 Link LK1 .................................................................................. 2-6
2.3.3.2 Links LK2, LK3, LK4 and LK5 ................................................. 2-7
2.3.4 PCB INTERCONNECTIONS .................................................................. 2-7
2.4 INSTALLATION ........................................................................................ 2-8
2.4.1 MECHANICAL INSTALLATION ............................................................. 2-8
2.4.2 ELECTRICAL INSTALLATION ............................................................. 2-10
2.4.2.1 Electrode Connections .......................................................... 2-10
2.4.2.2 Connecting Cables to Water Column Electrodes ................. 2-11
2.4.2.3 Connecting the Electrode Cable Assemblies to 2468
Enclosure………………………………………………………....2-12
2.4.2.4 Hydrastep Power Supply Cables .......................................... 2-13
2.4.2.5 Analogue Output Connection ................................................ 2-15
2.4.2.6 Opto-Isolated Fault Output Connection ................................ 2-16
2.5 SYSTEM CONFIGURATION .................................................................. 2-17
2.5.1 INPUT BOARD (PCB 24680501 OR 24680516) ................................. 2-17
2.5.1.1 Analogue Output Configuration ............................................. 2-17
2.5.1.2 Pulsed Output Setting ........................................................... 2-18
2.5.1.3 Electrode Error Configuration ............................................... 2-18
2.5.1.4 Configuring the Unit to Detect Electrode Error ..................... 2-19
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-2 24685034
2.5.2 DISPLAY BOARD 24680515 ............................................................... 2-20
2.5.2.1 Link LK1 Setting .................................................................... 2-20
2.5.2.2 Configuring the ‘Number of Electrodes’ Switch .................... 2-20
2.5.2.3 ‘Switching Threshold’ Setting ................................................ 2-22
2.5.2.4 ‘Compatibility’ Setting ............................................................ 2-22
2.6 FAULT ANALYSIS & CORRECTIVE ACTION ....................................... 2-23
2.6.1 COMPONENT REPLACEMENT .......................................................... 2-30
2.6.1.1 Removing the Input Board (24680501 or 24680516) ........... 2-30
2.6.1.2 Refitting the Input Board ....................................................... 2-30
2.6.1.3 Removing the Display Board 24680515 ............................... 2-30
2.6.1.4 Refitting the Display Board ................................................... 2-30
2.6.2 PARTS LIST - HYDRASTEP 2468 CB & CD VERSIONS ................... 2-31
2.7 SPECIFICATION ..................................................................................... 2-32
Illustrations
Figure 2.1: Outline drawing showing PCB layout and interconnections ............................... 2-4
Figure 2.2: Installation diagram for Hydrastep 2468 Electronic Gauging System unit ......... 2-9
Figure 2.3: Enclosure cable layout for 16 electrode system ............................................... 2-12
Figure 2.4: Voltage Selection (240V or 110V) .................................................................... 2-14
Figure 2.5- Location of display board links LK1 to LK5 & switch SW1 with configuration…..….
details………………………………………………………………………………….2-21
Figure 2.6- Split pads SP1, SP2, SP5 & SP6 locations and settings ................................. 2-22
Tables
Table 2.1 - Analogue output configurations ...................................................................... 2-17
Table 2.2 - Number of electrodes being displayed ........................................................... 2-20
Table 2.3 - Fault analysis/corrective action chart ............................................................. 2-23
Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version
24685034 2-3
2.1 INTRODUCTION
This chapter introduces the dual power supply version of the Hydrastep 2468 Electronic
Gauging System, its mechanical installation, system configuration, simple fault
analysis/corrective action capability and its specification.
2.2 ELECTRODE CABLING SYSTEM
This system can have 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 or 32 electrodes and uses
18-core electrode cables. The cables consist of nine pairs of coloured cores with the black
cores in each cable used for the EARTH terminations. Each electrode requires one pair of
cores, one core for the signal drive and one for the signal return.
Number of
Electrodes Number of Cables
Required
8
10-16
18-24
26-32
1
2
3 or 4
4
The electrode cable is pre-formed for simple installation. The connections to the electrodes
are terminated on the connection stud of the electrode. Either core can be connected to the
electronic enclosure as the signal drive or return.
2.3 ELECTRONIC ENCLOSURE
The basic arrangement of boards in the electronic enclosure is as follows:
Two input boards supply power to the system and to the input signal processing
circuits. These boards are: PCB 24680501, ac (mains) input, or PCB 24680516, dc
input. One board is mounted on the right hand side of the base plate and receives the
odd numbered electrode inputs. The other board is mounted on the left hand side of
the base plate and receives the even numbered electrode inputs.
A display board (PCB 24680515) contains the LED drive circuits for the two columns
(32 red LEDs and 32 green LEDs) and the system fault LEDs. This board is mounted
on the rear of the front panel, with the LEDs protruding through the front panel.
Up to four output boards, Relay Board (PCB 24680504), Relay with time delay Board
(24680509) or Opto-isolator Board (PCB 24680505) may be fitted, two per input
board. Output board mounting pillars are fitted to each input board during
manufacture to support the first output board mounted.
Refer to Figure 2.1 on page 2-4 for an annotated view of the internal layout of the unit.
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-4 24685034
Figure 2.1: Outline drawing showing PCB layout and interconnections
Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version
24685034 2-5
2.3.1 INPUT BOARD (PCB 24680501 AND PCB 24680516)
The input board processes the electrode inputs to provide water level data for display
purposes and a current output representing the water level. Fault detection is also carried
out where the condition of the electrode inputs are examined and a FAULT is indicated
when:
1. An open circuit in either of the electrode conductor cores is present.
2. A short circuit to EARTH on either the electrode or conductor cores.
3. A water above steam condition exists.
4. An internal circuit fault condition exists.
A current output circuit is also provided on each input board. This gives an analogue
representation of the water level. The sense (forward or reverse) and type (0-20mA or
4-20mA) is selectable and described in Section 2.5 of this chapter. Fault indication on the
analogue output is an oscillating waveform (of approximately 0.5 Hz) superimposed on the
main analogue signal.
The electrode inputs to each input board are passed to the other input board so that each
analogue circuit can output the full range content of electrode input signals. However,
should either of the input boards fail, the remaining board recognises that data is missing
and doubles its own electrode input signal to remedy the data loss giving a maximum error of
± 1 electrode.
Provision is made on each input board to accept one or two output boards, either relay
outputs or opto-isolated outputs. Both types of output board are offered as options.
Each input board produces the power supplies for the whole instrument which are derived
either from the local mains voltage supply of 110V ac or 240V ac nominal for the 24680501
input board or 20V dc to 40V dc for the 24680516 input board.
Apart from the input voltage there are two other differences between the AC (24680501) and
DC (24680516) input boards. These are the analogue output drive capability and the
remote display drive capability.
2.3.1.1 Analogue Output Drive Capability
With the minimum DC supply voltage of 20V for the DC input board (24680516) the
maximum load that can be driven by the analogue output is 500.
At the minimum mains input voltage the AC input board (24680501) the maximum load that
can be driven by the analogue output is 600.
2.3.2 REMOTE DISPLAY DRIVE CAPABILITY
The remote display drive capability is only a consideration when the 2468C is providing
power for a remote display. With either input board the unit is capable of driving six remote
displays at up to 1000m (3280ft) from the unit but only powering one remote display (any
others must be locally powered). With the AC input board the maximum cable loop
resistance to the remote display is 27 whilst with the DC input the maximum cable loop
resistance to the remote display is 7. (See remote display section for more details).
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
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2.3.3 DISPLAY BOARD (PCB 24680515)
The display board receives its power supplies and electrode data from the input boards.
This data is decoded and used to illuminate the required LEDs mounted on the display
board. The data is also converted to serial format for transmission to remote display units.
The water level in the column is indicated on the front panel by two columns of 32 LEDs, one
green column to indicate the electrodes which are in water and one red column to indicate
the electrodes which are in steam. The number of LEDs illuminated is dependent on the
number of electrodes being used in the system. When 8 to 16 electrodes are being used,
the unit illuminates two LEDs per electrode. When between 18 and 32 electrodes are being
used, the unit illuminates one LED per electrode. In both cases, the display is top biased
(unused LEDs are at the bottom of the display). A blanking label is provided to mask any
LEDs that are not used.
The system fault is indicated by the yellow LED. Provision is also made for external
indication of a system fault. This takes the form of an opto-isolated output which is normally
in its short-circuit state. When an alarm condition exists, the opto-isolated output is open-
circuited.
Full illumination of the Fault LED indicates a water above steam condition has been
detected. Illumination of half the Fault LED indicates an electrode, wiring or input board
related fault. The top half of the Fault LED illuminates when faults are detected by the left
hand input board (the even electrodes) and the bottom half of the Fault LED illuminates
when faults are detected by the right hand input board (the odd electrodes). Faults are
covered under “Fault Analysis & Corrective Action” in section 2.4 of this chapter.
The switch that sets the number of electrodes to be scanned is also mounted on this board.
A ‘chequered pattern’ is displayed by the RED and GREEN columns if an invalid switch
setting is made on the number of electrodes switch.
The water/steam switching threshold (0.6S/cm or 1.6S/cm) may be changed by solder
split pads.
2.3.3.1 Link LK1
The display board caters for both single input board and dual input boards versions of the
Hydrastep 2468 system. With dual input boards, the odd electrode inputs are connected to
one half of the display board circuit with the even electrode inputs connected to the other half
of the circuit.
With the single input board, only one half of the board is connected to the odd and even
electrode inputs. In this case the link LK1 must be fitted to connect the odd and even
halves of the display board circuit.
Note: This link MUST be removed for the dual input board system.
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2.3.3.2 Links LK2, LK3, LK4 and LK5
These links are used to select either the 8 - 16 display mode (two LEDs per electrode) or the
18 - 32 display mode (one LED per electrode).
Two link headers are provided with the unit and must be fitted in either LK2 and LK4, to
enable the 8 - 16 electrode mode, or LK3 and LK5, to enable the 18 - 32 electrode mode.
No. of Electrodes used Link Headers fitted
8 - 16 electrodes LK 2 & LK 4
18 - 32 electrodes LK 3 & LK 5
See also Figure 2.5 on page 2-21.
2.3.4 PCB INTERCONNECTIONS
Signal interconnection between the input boards and the display board is via ribbon cables.
The power supplies to the display board come from each input board via a 6-core cable.
Slots are provided in the base plate to guide the cables towards the hinge-side of the
enclosure case, thus minimising any cable strain when the enclosure lid is opened. See
Figure 2.1 for layout details.
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2.4 INSTALLATION
This section deals with the mechanical installation of the electronic enclosure and the
electrical connections required for the basic system. Any installation dealing with the options
available for use on this version of the system are covered in Chapters 3 & 4.
Notes:
1. The Electronic Enclosure cover should not be removed or opened until the equipment is
ready for physical installation to its fixing point. Under no circumstances should the
Electronic Enclosure be left open unless internal work is actually in progress.
2. When working on a bench with the enclosure open, the lid should be supported in its
open position.
3. To clean the instrument, use a damp cloth with a mild, water-based cleaner. Clean the
exterior of the instrument only. Do not allow liquids to enter or spill into the instrument.
2.4.1 MECHANICAL INSTALLATION
The electronic enclosure must be sited within electrode cable length of the water column fixture.
The preferred site for the electronic enclosure is a wall or vertical bracket structure where easy
access is available for viewing and servicing, and of suitable composition/load bearing ability to
be capable of supporting 4 times the equipment weight (see page 2-32 for weight specification.)
It is assumed that the water column is fully installed.
The electronic enclosure is equipped with four welded feet, allowing it to be secured in a
vertical position. Using a template derived from the enclosure details, given in Figure 2.2,
drill the necessary holes in the prepared surface. Secure the electronic enclosure with M10
bolts or equivalent fixings.
The wiring enters the unit through a gland plate in the bottom of the enclosure. A blank
gland plate is provided to give users a choice in the type of glands and gland configuration
for the required system. Alternatively, cable entry can be made directly via trunking. Note
that the gland plate should be removed for fitting of the glands. EMC compatibility for
European installations is proven for an enclosure using a gland plate and RF glands making
a good annular (ring shape) connection to screened cables for all connections. An
installation using unscreened cables or trunked routing without a gland plate and RF gland
would not be covered by the manufacturer’s EMC declaration of conformity.
The cabling involved is:
Mains Supplies (2 cables) Remote Display (up to 6 cables)
Electrode Inputs (up to 4 cables) Analogue Outputs (1 or 2 cables)
Relay or Opto-isolated Outputs Opto-isolated Fault Output (1 cable)
(Up to 16 relay or opto-isolated outputs)
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Figure 2.2: Installation diagram for Hydrastep 2468 Electronic Gauging System unit
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2.4.2 ELECTRICAL INSTALLATION
This section deals with the interconnection between the electrodes and the electronic
enclosure, the connection of the ac mains power supply to the electronic enclosure and the
analogue output connections from the electronic enclosure.
2.4.2.1 Electrode Connections
Hydrastep Electrode Cables
Special electrode cable assemblies of length 3, 10, 18 or 30 metres are provided with the
system for connecting the Hydrastep 2468 Electronic Enclosure to the Water Column
Electrodes. The cable looms are 18-core multi-strand conductors.
The conductors are colour coded for ease of installation and have pure nickel ring clamps
fitted at one end for connection to the electrodes. A set of wire crimps is provided for use on
the Enclosure connections.
The black conductors in each cable are used for the EARTH terminations, leaving eight
pairs of coloured conductors for connection to the electrodes. At least one cable assembly is
required and certain conductor pairs in the cables will be redundant. The exceptions are the
8, 16 and 32 electrode systems where all the conductors in the cables are fully used.
Electrode connections
Pin
Number Function PL2, PL3, PL4, PL5
1 Electrode Drive
2 Electrode Pickup
3 Functional Earth
4 Electrode Drive
5 Electrode Pickup
6 Electrode Drive
7 Electrode Pickup
8 Functional Earth
9 Electrode Drive
10 Electrode Pickup
The connection requirements for
the 16 electrode system is used as
the example case. A full set of
electrode connection diagrams is
included at the end of Chapter 2
covering the pin-by-pin pairings for
all electrode systems mentioned.
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2.4.2.2 Connecting Cables to Water Column Electrodes
(16 Electrode System - See Page 2-WD.7)
The following assumes that the electrodes have been fitted to the water column.
1. Gain access to the electrodes mounted on the water column.
2. Undo both knurled nuts on the stud of the bottom electrode (referenced EL.1 on the
drawings) and remove both the nuts and washers.
3. Take one of the brown (BN) conductors in Cable 1 and fit the ring clamp of the
conductor over the stud, followed by a washer and a knurled nut. Tighten the nut to form
a good secure contact, ensuring the conductor run to the cableform clamping bar is free
from snags and sharp bends.
4. Repeat the operation for the remaining brown (BN) conductor of Cable 1.
5. Take the next electrode up, referenced EL.2 on the drawings, and repeat the operations
detailed in paragraph 2 above.
6. Take the brown (BN) conductors of Cable 2 and repeat the fitting instructions detailed in
paragraph 3 above.
7. Repeat the operations of paragraphs 2 and 3 for the remaining tabulated
conductor/electrode pairings on the next page and connect as detailed on page 2-WD.7.
8. Check that all conductor runs affecting Cables 1 and 2 on the water column are
satisfactory then clamp the cable securely to its clamping bar.
9. Refit any Electrode Protection Covers to the water column.
Water column connections for 16 electrodes
Electrode
Number Conductor
Number Cable
Number Enclosure
Connection Electrode
Number Conductor
Number Cable
Number Enclosure
Connection
1 Brown 1 PL2 pin 1 10 Green 2 PL3 pin 1
Brown PL2 pin 2 Green PL3 pin 2
2 Brown 2 PL2 pin 1 11 Blue 1 PL3 pin 4
Brown PL2 pin 2 Blue PL3 pin 5
3 Red 1 PL2 pin 4 12 Blue 2 PL3 pin 4
Red PL2 pin 5 Blue PL3 pin 5
4 Red 2 PL2 pin 4 13 Purple 1 PL3 pin 6
Red PL2 pin 5 Purple PL3 pin 7
5 Orange 1 PL2 pin 6 14 Purple 2 PL3 pin 6
Orange PL2 pin 7 Purple PL3 pin 7
6 Orange 2 PL2 pin 6 15 Grey 1 PL3 pin 9
Orange PL2 pin 7 Grey PL3 pin 10
7 Yellow 1 PL2 pin 9 16 Grey 2 PL3 pin 9
Yellow PL2 pin 10 Grey PL3 pin 10
8 Yellow 2 PL2 pin 9 Earth Black 1 PL2 pin 3
Yellow PL2 pin 10 Black PL2 pin 3
9 Green 1 PL2 pin 9 Earth Black 2 PL2 pin 3
Green PL2 pin 10 Black PL2 pin 3
Note: There are two conductors of each colour per cable.
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Figure 2.3: Enclosure cable layout for 16 electrode system
2.4.2.3 Connecting the Electrode Cable Assemblies to 2468 Enclosure
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Four 10-way plugs are provided on each PCB1 to terminate all the necessary connections
from the electrode cables.
1. Ensure power is removed from electronic enclosure and open the front cover.
2. Feed Cables 1 and 2 into the enclosure through its gland (if applicable). Prepare the
cable screens and terminate the screens at the gland plate.
Screened cables must be used, and each one grounded at the cable gland entering the
enclosure. Use a good quality RF cable gland and ensure a good annual (ring shape)
connection with the screen. The screens should not be grounded at the electrode end.
3. Prepare the individual conductor lengths to suit their orientation in the terminal blocks
PL2 and PL3 on their respective PCB 24680501 as shown in Figure 2.3.
It is considered good practice to twist wire-pairs together for each electrode circuit, and
twist the pairs that are in the same cable together into one bundle.
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Wiring to the ‘hinge-side’ 24680501 board (even-numbered electrodes) should not be
pressed hard against the ribbon cables, but instead run forward of the connectors and
away from the side of the casing. Do not route them over the board.
Wiring to the ‘catch-side’ 24680501 board (single channel set-up / odd-numbered
electrodes) should be tucked into the back of the enclosure, next to the connectors, as
close to the casing as possible and below the base plate level.
4. Fit the free sockets into the terminal blocks PL2 and PL3.
5. Prepare the conductor core ends, fit the crimp terminals and connect the conductors to
their respective free sockets.
6. Ensure that both cables have a stress-free run inside the enclosure.
2.4.2.4 Hydrastep Power Supply Cables
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
AC Powered Units (input board 24680501)
The Hydrastep 2468C must be installed with a fuse or circuit breaker with a maximum rating
of 5A mounted as close as practicable, in an easily reached location. The fuse or circuit
breaker must be uniquely identified as the disconnecting device.
The cable gland used must have an inlet or bushing with a smoothly rounded bell-mouthed
opening with a radius of curvature of at least one and a half times the overall diameter of the
mains cable fitted. Alternatively, a fixed guard made of insulating material protruding beyond
the inlet opening by at least five times the cable diameter may be used.
A shielded power cable, and shielded signal cables with the connection to the unit through
RF glands mounted on the gland plate should be used for all units that need to comply with
the requirements of the European EMC Directive.
Gain access to each input board and proceed as follows:
1. Ensure that the mains cable is safely isolated before starting work, and ensure that
enough length is prepared to install it according to the route described in Step 2 and
Step 3 below. The power inlet must be dedicated to that function only. No signal wiring
must share the power inlet cable. Two separate protected AC mains circuits (of the
same electrical phase) may be provided in a suitably rated multi-way cable.
2. Use a good quality RF cable gland, and ensure there is a good annular (ring shape)
connection with the screen. A ferrite (supplied) must be attached inside the unit to each
supply input, as close to the inlet gland as possible. Make a double-turn through each
ferrite – ensure that the cable is prepared with enough length to accommodate this –
and have the entire run stress-free.
3. Route the cables to both boards along the right-hand (catch) side of the enclosure.
The supply wiring to the even-numbered electrode boards should run up the right-hand
side and across the top of the enclosure. Do not run it close to the display board ribbon
cables. The run must be stress-free, and it is good practice to twist power pairs
together. The use of a self-adhesive cable tie (not supplied) is recommended to hold the
power cables close to the metalwork and away from the PCB.
4. Connect the live and neutral conductor to their respective terminals.
5. Check the voltage setting by checking which voltage selection plug is fitted (set to 240V
at the factory) and, if required, adjust as guided in Figure 2.4.
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6. With power disconnected release voltage selection plug PL9 by squeezing lugs. Insert
appropriate selector plug.
7. Remove fuse and fit 200mA ceramic anti-surge fuse for 240Vac nominal and 400mA
ceramic anti-surge fuse for 110Vac nominal.
The Hydrastep 2468C unit must be earthed via the protective earth terminal (stud) on
the enclosure. The cable or braid used to attach the unit to the protective earth must
be capable of carrying a current of at least 10A. No disconnecting device should be
fitted to the protective earth conductor.
TRANSFORMER
Fuse
LN
Voltage Selection Plug
(Set to 110V)
TRANSFORMER
Fuse
LN
Voltage Selection Plug
(Set to 240V)
(A) 240V (B) 110V
Figure 2.4: Voltage Selection (240V or 110V)
DC Powered Units (input board 24680516)
A shielded power cable, and shielded signal cables with the connection to the unit through
RF glands mounted on the gland plate should be used for all units that need to comply with
the requirements of the European EMC Directive. The supply is connected to the unit in the
same way as for the AC version. A ferrite (supplied) must be attached inside the enclosure
for each DC inlet (with a double-turn). The DC inlet must not be shared by signal wiring for
any other purpose. Route the supply wires in twisted pairs as described in the AC section.
The DC supply must be either negative earth of fully isolated from plant ground
1. Positive (+Vs) is connected to the terminal marked L.
2. Negative (-Vs) is connected to the terminal marked N.
3. A separate ground wire is required which must be connected to the earth stud on the
enclosure.
4. For a non-isolated supply, the maximum difference between the plant earth at the water
column and the -Vs supply is 7V.
5. Use a good quality RF cable gland, and ensure there is a good annular (ring shape)
connection with the screen.
The Hydrastep 2468C unit must be earthed via the protective earth terminal (stud) on
the enclosure. The cable or braid used to attach the unit to the protective earth must
be capable of carrying a current of at least 10A. No disconnecting device should be
fitted to the protective earth conductor.
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2.4.2.5 Analogue Output Connection
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Plug PL1 on each input board is used for the analogue output. A 2-core screened cable is
required and is connected into a 2-way socket such that:
The positive output conductor terminates in socket SK1 pin 1.
The negative output conductor terminates in socket SK1 pin 2.
Gain access to each PCB 24680501 and connect the analogue output cable as follows:
1. Pass the analogue cable through its gland
(if applicable) and into the enclosure.
2. Prepare the analogue cable to give a stress-
free run to PL1 on each PCB 24680501,
allowing for a double-turn to pass through a
ferrite.
Analogue wiring must not share cables with
power input, electrode input, or relay output.
It is considered good practice to twist the analogue pairs together.
3. Use a good quality RF cable gland, and ensure there is a good annular (ring shape)
connection with the screen. A ferrite (supplied) must be attached to each analogue pair
inside the enclosure, as close to the cable gland as possible. Make a double-turn through
each ferrite.
4. Prepare the conductor ends, fit the crimp connectors and connect the cores into their
respective socket SK1 terminals.
5. Fit the socket into plug PL1 and check the cable run.
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2.4.2.6 Opto-Isolated Fault Output Connection
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Plug PL4 is used for the FAULT output. A 2-core screened cable, capable of taking 1A and
30V is required and is connected into its 2-way terminal block such that:
Note: No fault present = Short circuit, < 1.1V at 1 Amp
Fault present = Open circuit, < 1 mA at 30V
The positive output conductor terminates in socket PL4 pin 2.
The negative output conductor terminates in socket PL4 pin 1.
Gain access to PCB 24680515 and connect the FAULT output cable as follows:
1. Prepare the FAULT output cable to give a stress-free run to PL4 on PCB 24680515.
Fault output wiring must not share cables with power inputs or electrode inputs, and is
considered good practice to twist the FAULT cable pairs together.
2. Use a good quality RF cable gland, and ensure there is a good annular (ring shape)
connection with the screen.
3. Prepare the conductor ends and connect the conductors into their respective terminal.
Check the cable run and tie it to the present loom. Tighten the gland nut (if applicable)
and close the instrument front cover.
Part of Display Board showing PL4
If the installation is adversely affected by the operation of nearby equipment, then re-routing
the cables to these instructions should improve the performance:
Avoid bundling the cables from both channels together
Ensure that cables run against earthed metalwork where possible
Use screened cables for all connections, making sure that a good annular (ring shape)
connection is made with a good quality RF cable gland
Electrode, Relay, and Analogue Output wiring on the left-hand (enclosure hinge) side should
not be pressed hard against the ribbon cables, but instead run forward of the connectors and
away from the side of the casing. Do not run the wiring over the PCB.
Wiring on the right-hand (enclosure catch) side should be tucked into the back of the enclosure,
next to the connectors, and as close to the casing as possible and below the vase plate level.
Supply wiring should be run close to the metalwork, forward of the signal wiring, but never
along the left-hand (hinged) side of the enclosure near the ribbon cables.
The ribbon cables must be run under the back plate and up the left-hand (hinged) side of the
enclosure, and secured by using clips (supplied).
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This concludes the electrical installation requirements for the basic instrument configuration.
Connections within the enclosure for the options available will be covered in the Installation
sections of the appropriate Chapter 3a (Relay Outputs), 3b (Relay with time delay Outputs),
3c (Opto-isolated Outputs) or Chapter 4 (Remote Display).
2.5 SYSTEM CONFIGURATION
This section describes mains voltage selection, analogue output setting and electrode error
configuration on each input board. Also the ‘number of electrodes’ setting and configuration
of the water/steam switching threshold value display board is described.
The three main PCBs require configuration. These are:
Two Input Boards - PCB 24680501 or 24680516
Display Board - PCB 24680515
2.5.1 INPUT BOARD (PCB 24680501 OR 24680516)
Two settings may be configured on this board, the analogue output range and sense, and
the electrode error configuration.
2.5.1.1 Analogue Output Configuration
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Two sets of split pads are provided to select the required range (0-20mA or 4-20mA) and the
sense of the mA current output (normal sense as shown or in reverse, i.e. 4-20mA or 20-4mA).
To configure the analogue output, refer to Table 2.1 then:
1. Ensure the power supply is disconnected.
2. Locate the position of split pads SP1 and SP2 on the input board (PCB).
3. Refer to Table 2.1, select which configuration is required and where ‘bridged’ is ticked,
bridge the gap on the pad with solder. Where ‘open circuit’ is ticked, ensure that any
solder bridge on the split pad is removed and the gap is clean.
4. Carry out a resistance test across any altered split pad for short circuit or open circuit
conditions as appropriate.
Table 2.1 - Analogue output configurations
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2.5.1.2 Pulsed Output Setting
As configured at the factory, the analogue output pulses if a fault condition occurs.
1. To disable this feature the split pad SP10 must be broken by cutting the track that
passes between the pads.
2. To re-enable the pulse for fault conditions the split pad can be bridged with solder.
2.5.1.3 Electrode Error Configuration
An electrode error is triggered if the electrode resistance measured falls below the set
electrode error threshold. Possible causes are a short to ground (short in cabling or dirty
electrode) or a break in the electrode wire (may also be very conductive water). This unit
can either be configured to take electrode error into account when measuring electrode
resistance or the facility can be disabled. When enabled, if an electrode error occurs the
alarm (yellow) LED relating to the board on which the error occurred is illuminated and the
LED pair (red and green) corresponding to the electrode, alternate between red and green.
Input Board (Option Board Removed)
Note: If SP6 has been bridged, this may be left in
position even if SP7 is subsequently bridged.
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2.5.1.4 Configuring the Unit to Detect Electrode Error
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Disconnect the power supply. Gain access to the input PCB by opening the cover and
removing the option board.
2. Check split pads SP6 & SP7 on the input PCB are open circuit and clean (this is the
default setting).
3. To change the electrode error threshold value or to disable the feature, bridge the split
pads SP6 or SP7 with solder as shown in the table above.
Repeat the procedure used in configuring the first input board to set up the remaining input
board as required. This concludes the configuration on the input boards.
WARNING Bridging SP7 will disable the electrode fault alarm. In this
condition, a fouled electrode in water will not be detected.
This is of particular importance when electrodes are used
for low level alarm or cut off.
By bridging split pad 6 on the input board, the conductivity fault detection level will be increased
from 104S (normal) to 300S (high). This may be sufficient in some cases, but not all.
Factory modifications are available to further increase this level to 800S, 1600S or
2000S. At each of these stages, the measuring sensitivity of the Hydrastep system is
reduced, so the most appropriate level should be chosen, not the highest. Contact your local
representative for further details.
Note that input boards that have been modified are marked with the number 24680229A and
the conductivity level that is acceptable.
Offset voltages:
When an offset voltage is present on the return
signal and is relatively high compared to the ac
voltage, it may have the effect of lifting the
square wave to the water/steam switching point.
This will cause one, or more, electrodes to flash
rapidly on the display as the detection circuits
alternate between steam and water. When
combined with the problem described above, the
display becomes very confusing.
Input adapter boards (24680523A) are available
which fit into the electrode cable connectors on
the input board (see inset picture, right). These
have series capacitors in the return side of the
cables, blocking any dc offset voltages.
The electrode cable then plugs into the Input
Adapter Board instead of the electrode cable
connector.
1. Input Adapter Board.
2. Input Board (Partial Top View).
3. Adapter plugged into electrode cable connector
(Horizontal View).
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2.5.2 DISPLAY BOARD 24680515
The Display Board needs to know how many electrodes are being used and if one or two input
boards are being used. A centrally mounted dual-in-line switch assembly, SW1 (titled “Number
of Electrodes”) uses four individual switch channels to select between an 8 and 32 electrode
operation as shown in Table 2.2 below. A socket LK1 (situated near switch SW1) is provided to
link the two halves of the display board together with a link header when only one input board is
used. In this case when two input boards are being used, the link header is not fitted.
Sockets are also provided at LK2, LK3, LK4 and LK5 locations (see Figure 2.5), to select an
8 - 16 (two LEDs per electrode) display mode or an 18 - 32 (one LED per electrode) display
mode. For hazardous area applications, links 2, 3, 4 and 5, when fitted, must be secured
into the sockets using a cable tie passed underneath the socket base.
SWITCH SW1 NO. OF ELECTRODES LINKS 2-5
CHANNEL NO. IN WATER PER INPUT LINKS LINKS
1 2 3 4 COLUMN BOARD 2 & 4 3 & 5
Off Off On On 8 4
On On Off On 10 5 Fitted Not
Off On Off On 12 6 Fitted
On Off Off On 14 7
Off Off Off On 16 8
On On On Off 18 9
Off On On Off 20 10
On Off On Off 22 11
Off Off On Off 24 12 Not Fitted
On On Off Off 26 13 Fitted
Off On Off Off 28 14
On Off Off Off 30 15
Off Off Off Off 32 16
Table 2.2 - Number of electrodes being displayed
2.5.2.1 Link LK1 Setting
Ensure that link header LK1 is not fitted (see Figure 2.5).
2.5.2.2 Configuring the ‘Number of Electrodes’ Switch
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Disconnect the power supply. Gain access to PCB 24680515 by opening the cover.
2. Locate position of ‘Number of Electrodes’ switch SW1 see Figure 2.5.
3. Depending upon the number of electrodes being used, set the switches as defined in
Table 2.2. The switch positions in the example shown are for a twelve electrode system.
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Figure 2.5- Location of display board links LK1 to LK5 & switch SW1
with configuration details
Note: When two input boards are fitted, odd
electrodes use one input board, even
electrodes use the other input board, and
switch SW1 is set to the number of electrodes
per input board.
For 18 – 32 electrodes, links LK3 and LK5
must be fitted.
For 8 – 16 electrodes, links LK2 and LK4
must be fitted.
An invalid switch setting causes the main
column LEDs to display a chequered pattern.
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2.5.2.3 ‘Switching Threshold’ Setting
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Disconnect the power supply. Gain access to PCB 24680515 by opening the cover.
2. Check split pads SF1 & SP2 on the PCB are open circuit and clean (this is the normal
setting 0.6S/cm). See Figure 2.6 for details.
3. If the preferred setting is 1.6S/cm (i.e. low temperature), bridge the split pads SP1 &
SP2 with solder.
Figure 2.6- Split pads SP1, SP2, SP5 & SP6 locations and settings
2.5.2.4 ‘Compatibility’ Setting
The split pads SP5 and SP6 should be open when used with a 24680501C or 24680516B
input board. When used with a 24680501A, 24680501B or 24680516A input boards these
split pads should be made. With these older input cards the LEDs corresponding to an
‘electrode error’ will not alternate but remain steady.
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2.6 FAULT ANALYSIS & CORRECTIVE ACTION
Faults in the system will generally be indicated by the YELLOW LED on the front panel and
by the fault output on the display board. The main faults, which are catered for, are:
Water above steam condition
Electrode or Wiring fault
Detection of an internal circuit fault
When any of the above mentioned conditions exist within the Hydrastep 2468CB system, the
yellow LED is illuminated to indicate the FAULT state. Since the electrode inputs are split
between the two input boards, the ALARM indicator is configured to differentiate between
ODD and EVEN electrode faults. An opto-coupler output, normally short-circuited, becomes
open-circuited on a FAULT state, providing an ALARM indication output for external use.
The current output indicates an alarm condition by a 0.5Hz waveform superimposed on the
main analogue signal.
A further FAULT is indicated when the number of electrodes switch on the display board is
set to an invalid number. This error brings up an alternate LED illumination display, that is a
chequered display of GREEN and RED LEDs on the two front panel columns.
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Some parts of the water column and electrodes may be
very hot. Please ensure parts are adequately cooled or that
suitable precautions are taken before handling.
Indication Fault(s) Analysis and Corrective Action
State 1
Top and
bottom
halves of
fault LED
illuminated
One or more
LED pairs
alternating
between
water and
steam
Water conductivity.
All LED pairs in water
alternating between
water and steam.
Check ac voltage on all electrodes immersed in
water with a true r.m.s. voltmeter. If several of the
immersed electrodes show a voltage of less than
approximately 0.1V ac then very high water
conductivity is probable.
Check water column installation is correct; sloping
pipework and insulation details. Make sure that
there is sufficient condensate flow through the
column.
If the normal water conductivity is high, the
electrode error circuit can be de-sensitised or
disabled.
If the normal water conductivity is still too high
(40mV ac at electrode), the electrode error circuit
must be disabled – refer to the electrode error
configuration section.
Water above steam,
caused by electrode
wiring or internal fault
Electrode connection
open-circuit or short-
circuit to earth
The electrode channel(s) causing the problem will
be evident from the unit display by an alternating
indication in the steam area.
Check the suspect electrode(s) has the correct pair
of conductors connected, check the connections to
the input board. Rectify if incorrect.
Table 2.3 - Fault analysis/corrective action chart
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-24 24685034
Indication Fault(s) Analysis and Corrective Action
State 1 (contd.) Incorrect wiring,
broken connection
or damaged cable
assembly
Affected
electrode(s)
alternate between
water and steam.
Check ac voltage on electrodes with a true r.m.s.
voltmeter. A voltage of less than 0.1V ac indicates a fault
condition.
If wiring to the electrode is correct and the electrode
gives a voltage reading of greater than 0.1V ac and a
fault is still indicated, carry out the following procedure:
1. Remove both conductors from the suspect electrode.
With the conductors isolated from each other, the
level display should show the electrode as
alternating between water and steam (green and
red).
2. With the conductors touching each other, the level
display should show electrode as being in steam.
The above procedure checks the electrode wiring. If the
display does not show the correct results, then check for
a break in either of the suspect electrode conductors.
Carry out repair to any faulty connection or substitute a
new conductor or cable assembly in place of the
defective item.
Dirt on electrode
Affected
electrode(s)
alternate between
water and steam.
If the wiring checks carried out as described above have
not located a fault, then dirt on an electrode insulator may
be the cause of the problem giving an effective short-
circuit to ground.
Check the electrodes for dirt over the external insulator
and clean with a cloth as required.
Checking for dirt on the internal insulator of the electrode
requires the draining of the water column (refer to Part 2
of this manual for the correct procedure).
Once the water column is drained, check the ac voltage
on each electrode using a true r.m.s. voltmeter. Any
electrode showing a voltage of less than 3V ac needs
cleaning or replacement. Electrodes must be removed
from the column for inspection and cleaning.
Note: The electrode insulator can be cleaned using a
clean cloth
Internal fault If the wiring checks carried out as described above have
not located a fault, then it is possible an internal fault
exists.
1. Disconnect the electrode cable sockets from the
input board.
2. Make up four 10-way sockets (six or eight sockets
required for systems with more than 16 points) with
wire links connecting the following pins on each
socket; 1-2, 4-5, 6-7, 9-10.
Table 2.3 - Fault analysis/corrective action chart (continued)
Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version
24685034 2-25
Indication Fault(s) Analysis and Corrective Action
State 1 (contd.) 3. Insert these sockets in place of the electrode cable
sockets in the input boards, the level display should
now show an all steam state and no fault
indication. If this does not occur an internal fault
exists.
The circuit fault may be on either input board or the
display board. If spares are available, change the input
board first and if the fault is not rectified change the
display board. If spares are not available, call the
service engineer.
State 2
Top and bottom
halves of fault
LED illuminated
No LED pairs
alternating
between water
and steam
Internal fault This state is indicating a fault which is not related to an
electrode error because no LED pairs are alternating
between water and steam. It is therefore likely that an
internal fault exists.
Follow same procedure as above.
State 3
Top half of fault
LED illuminated
One or more
LED pairs
alternating
between water
and steam
Electrode wiring or
internal fault
Even numbered
electrode connection
open-circuit or
short-circuit to earth
Affected electrode
alternates between
water and steam.
Incorrect wiring,
broken connection or
damaged cable
assembly
Check that all even numbered electrodes indicating
water have the correct pair of conductors connected.
Check the connections to the left hand input board.
Rectify wiring if incorrect.
Check ac voltage on all even electrodes immersed in
water with a true r.m.s. voltmeter. A voltage of less than
0.1V ac indicates a fault condition.
If wiring to all even electrodes is correct and the
electrodes still give a voltage reading of greater than
0.1V ac and a fault is still indicated, carry out the
following procedure:
1. Remove both conductors from electrode 2. With the
conductors isolated from each other, the level
display should show electrode 2 as alternating
between water and steam (green and red).
2. With the conductors touching each other, the level
display should show electrode 2 as being in steam.
3. Repeat operations 1 and 2 for all affected even
numbered electrodes until a faulty indication is
found.
The above procedure checks the electrode wiring. If
the display does not show the correct results, then
check for a break in either of the suspect electrode
conductors.
Carry out repair to any faulty connection or substitute a
new conductor or cable assembly in place of the
defective item.
Table 2.3 - Fault analysis/corrective action chart (continued)
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-26 24685034
Indication Fault(s) Analysis and Corrective Action
State 3 (contd.)
Dirt on electrode
Affected electrode
alternates
between water and
steam.
If the wiring checks carried out as described above have
not located a fault, then dirt on an electrode insulator may
be the cause of the problem giving an effective short-
circuit to ground.
Check all even numbered electrodes alternating between
water and steam for dirt over the external insulator and
clean with a cloth as required.
Checking for dirt on the internal insulator of the electrode
requires draining of the water column (refer to the
appropriate manual for the correct procedure).
Once the water column is drained, check the ac voltage
on each even numbered electrode using a true r.m.s.
voltmeter. Any electrode showing a voltage of less than
3V ac needs cleaning or replacement. Electrodes must
be removed from the column for inspection and cleaning
Note: The electrode insulator can be cleaned using a
clean cloth
Internal circuit fault
on left hand circuit
board or the
display board
If the wiring checks carried out as described above have
not located a fault, then it is possible that an internal fault
exists.
1. Disconnect the electrode cable sockets from the
input boards.
2. Make up four 10-way sockets (six or eight sockets
required for systems with more than 16 points) with
wire links connecting the following pins on each
socket: 1-2, 4-5, 6-7, 9-10.
3. Insert these sockets in place of the electrode cable
sockets in the input boards. The level display should
now show an all steam state and no fault indication.
If this does not occur an internal fault exists.
The circuit fault may be on either input board or the
display board. If spares are available, change the left
hand input board first, and if the fault is not rectified
change the display board followed by the right hand input
board. If spares are not available, call the service
engineer.
State 4
Top half of fault
LED illuminated
No LED pairs
alternating
between water
and steam
Internal circuit fault
on left hand circuit
board or the
display board
This state is indicating a fault which is not related to an
electrode error because no LED pairs are alternating
between water and steam. It is therefore likely that an
internal fault exists.
Follow same procedure as above.
Table 2.3 - Fault analysis/corrective action chart (continued)
Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version
24685034 2-27
Indication Fault(s) Analysis and Corrective Action
State 5
Bottom half of
fault LED
illuminated
One or more
LED pairs
alternating
between water
and steam
Electrode wiring or
internal fault
Odd numbered
electrode
connection open-
circuit or
short-circuit to
earth
Affected electrode
alternates
between water and
steam.
Incorrect wiring,
broken connection
or damaged cable
assembly
Check that all odd numbered electrodes indicating
water have the correct pair of conductors connected.
Check the connections to the right hand input board.
Rectify wiring if incorrect.
Check ac voltage on all odd electrodes immersed in
water with a true r.m.s. voltmeter. A voltage of less than
0.1V ac indicates a fault condition.
If wiring to all odd electrodes is correct and the
electrodes still give a voltage reading of greater than
0.1V ac and a fault is still indicated, carry out the
following procedure:
1. Remove both conductors from electrode 1. With the
conductors isolated from each other, the level
display should show electrode 1 as being
alternating between water and steam (green and
red).
2. With the conductors touching each other, the level
display should show electrode 1 as being in steam.
3. Repeat operations 1 and 2 for all affected odd
numbered electrodes until a faulty indication is
found.
The above procedure checks the electrode wiring. If the
display does not show the correct results, then check for
a break in either of the suspect electrode conductors.
Carry out repair to any faulty connection or substitute a
new conductor or cable assembly in place of the
defective item.
Dirt on electrode
Affected electrode
alternates
between water and
steam.
If the wiring checks carried out as described above have
not located a fault, then dirt on an electrode insulator
may be the cause of the problem giving an effective
short-circuit to ground.
Check all odd numbered electrodes alternating between
water and steam for dirt over the external insulator and
clean with a cloth as required.
Checking for dirt on the internal insulator of the
electrode requires the draining of the water column
(refer to the appropriate manual for the correct
procedure).
Once the water column is drained, check the ac voltage
on each odd numbered electrode using a true r.m.s.
voltmeter. Any electrode showing a voltage of less than
3V ac needs cleaning or replacement. Electrodes must
be removed from the column for inspection and
cleaning.
Note: The electrode insulator can be cleaned using a
clean cloth
Table 2.3 - Fault analysis/corrective action chart (continued)
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-28 24685034
Indication Fault(s) Analysis and Corrective Action
State 5 (contd.)
Integral circuit fault
on right hand circuit
board or the display
board
If the wiring checks carried out as described above
have not located the fault, then it is possible and
internal fault exists.
1. Disconnect the electrode cable sockets from the
input boards.
2. Make up four 10-way sockets (six or eight sockets
required for systems with more than 16 points) with
wire links connecting the following pins on each
socket: 1-2, 4-5, 6-7, 9-10.
3. Insert these sockets in place of the electrode cable
sockets in the input boards. The level display
should now show an all steam state and no fault
indication. If this does not occur an internal fault
exists.
The circuit fault may be on either input board or the
display board. If spares are available, change the right
hand input board first and if the fault is not rectified
change the display board, followed by the left hand
input board. If spares are not available, call the service
engineer.
State 6
Bottom half of
fault LED
illuminated
No LED pairs
alternating
between water
and steam
Internal circuit fault
on right hand circuit
board or the display
board
This state is indicating a fault which is not related to an
electrode error because no LED pairs are alternating
between water and steam. It is therefore likely that an
internal fault exists.
Follow same procedure as above.
Table 2.3 - Fault analysis/corrective action chart (continued)
Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version
24685034 2-29
Indication Fault(s) Analysis and Corrective Action
State 7
Only odd or
even LEDs
illuminated
No power to one
input board or a
power supply fault
Only odd LEDs illuminating indicates a problem with
the left hand input board. Only even LEDs illuminating
indicates a problem with the right hand input board.
Check the wiring to the unit from the mains supply
then check the following:
Fuse and fuse rating
Voltage and voltage setting
(See Section 2.2 & 2.3 of this chapter)
If none of these checks locate the problem and the
correct mains supply voltage is present at the input
board terminals then a circuit fault exists and
replacement of the faulty input board is required.
State 8
Chequered
pattern on RED
& GREEN LED
display
Wrong setting of
Number of
Electrodes switch
on display board
Refer to Section 2.3 of this chapter and ensure that the
switch is set correctly. If the display still shows a
chequered pattern then a circuit fault exists on the
display board and the board will need replacing.
State 9
ON/OFF pattern
on RED &
GREEN LED
display
Wrong setting of
Number of
Electrodes switch
or linking on LK2,
LK3, LK4, LK5
incorrect on display
board
As above
State 10
Lower
electrodes not
displayed
As above As above
Table 2.3 - Fault analysis/corrective action chart (continued)
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-30 24685034
2.6.1 COMPONENT REPLACEMENT
The Hydrastep 2468 contains no user-replaceable components. Board failure requires the
replacement of the entire printed circuit board.
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
2.6.1.1 Removing the Input Board (24680501 or 24680516)
The input board is secured on to the base plate of the electronic enclosure by seven set
screws and washers, distributed one at each corner of the board and three in the board
centre. See Figure 2.1. To remove the input board, carry out the following procedure:
1. Isolate the electronic enclosure from the ac (mains) or dc supply and open the lid.
2. Unplug the supply connector TB1.
3. Unplug the electrode input connectors PL2, 3, 4 and 5 as necessary and the analogue
output connector PL1 (if used) from the input board.
4. Disconnect the ribbon cable connector on the display board and the display board power
cable socket on the input board - see Figure 2.1 on page 2-4.
5. Undo the seven securing screws and remove them and their washers. Lift off the input
board from the base plate.
2.6.1.2 Refitting the Input Board
To refit the input board, carry out the removal procedure in the reverse order.
2.6.1.3 Removing the Display Board 24680515
The display board is attached to pillars mounted on the rear of the front panel by five
securing nuts and washers. See Figure 2.1 on page 2-4.
To remove the display board, carry out the following procedure:
1. Isolate the electronic enclosure from the mains supply and open the lid.
2. Disconnect the ribbon cable socket and the display board power cable socket from the
display board, see Figure 2.1. Remove remote display and system fault connections if
applicable.
3. Undo the five securing nuts and remove them and their washers. Lift off the display
board from the attachment pillars.
2.6.1.4 Refitting the Display Board
To refit the display board, carry out the removal procedure in the reverse order.
Note: Special attention must be taken to ensure the lid screening is satisfactory after any
display board refitting. The screening cable is taken to the bottom left hand securing
screw on the display plate and this connection must have good conductivity.
Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version
24685034 2-31
2.6.2 PARTS LIST - HYDRASTEP 2468 CB & CD VERSIONS
Item Description Mobrey
Part No. Item Description Mobrey
Part No.
Electronic Enclosure
Input PCB assembly (2468CB)
Fuse link 200mA (T) ceramic
Fuse link 400mA (T) ceramic
24680501C
K9634
K9635
Display PCB assembly
Header programmable (10-way)
Header programmable (8-way)
24680515B
399100380
399100390
Input PCB assembly (2468CD)
Fuse link 1.25A (T) ceramic
24680516B
360190320 Socket SK3 free (10-way)
Socket SK7 free (10-way) 351510140
351510140
Cable assembly (10-way)
24680210A Earth lead 24680216A
Socket SK1 free (2-way)
Socket SK2 free (10-way)
Socket SK3 free (10-way)
Socket SK4 free (10-way)
Socket SK5 free (10-way)
351502180
351510140
351510140
351510140
351510140
Electrode Cables
Electrode cable (3 metre)
Electrode cable (10 metre)
Electrode cable (18 metre)
Electrode cable (30 metre)
24680204A
24680205A
24680206A
24680207A
Input Adapter Board 24680523A
2468CB & 2468CD Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-32 24685034
2.7 SPECIFICATION
Enclosure: 425mm x 325mm x 163mm (16.7in x 12.8in x 6.4in)
Brushed stainless steel
Wall-mounting
lP65 / NEMA4X
Gland plate - stainless steel 250mm x 120mm
(9.8in x 4.7in)
Weight of unit: 12kg (26.4lb)
Operating temperature: -20C to +70C (-4F to +158F)
Relative humidity: up to 100%
Location: Indoor or outdoor
Power supply requirements: 115V ac nominal
(ac input) 93.5V - 130V ac / 48Hz - 65Hz
240V ac nominal
187V - 256V ac / 48Hz - 65Hz
Power supply loading (ac): 60VA maximum
Power supply requirements: 24V dc nominal
(dc input) 20-25V dc negative earth or isolated
Note: Under fault conditions, an overvoltage of 30V
can be withstood for short periods.
Power supply loading (dc): 60W maximum
Supply -Vs to plant ground: 7V maximum for non-isolated supply
Installation category: III
Outputs: Drive to remote display (6 or 8 wire)
Opto-isolated fault output
Analogue output
Analogue output:
Range: 0 - 20mA or 4 - 20mA, forward or reverse
Accuracy: ± 0.2mA
Drive capability: 600 at nominal supply voltage
500 at minimum supply voltage
Opto-isolated fault output:
Maximum open-circuit voltage: 30V dc
Maximum short-circuit current: 1A dc
Short-circuit voltage drop: 1.1V dc maximum at 1A dc
Open-circuit leakage current: 1mA maximum at 30V dc
Remote display drive:
Loop Resistance (ac powered unit): 27 maximum
Loop Resistance (dc powered unit): 7 maximum
Distance: 1000m (3280ft) maximum
Electrical connections: Plug-in screw terminals
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.1
2
Wiring Diagrams for
Dual Power Supply Version
Contents
Page No.
Figure 2.1 - Electrode cable connections to 8 port column ....................................... 2-WD.3
Figure 2.2 - Electrode cable connections to 10 port column ..................................... 2-WD.4
Figure 2.3 - Electrode cable connections to 12 port column ..................................... 2-WD.5
Figure 2.4 - Electrode cable connections to 14 port column ..................................... 2-WD.6
Figure 2.5 - Electrode cable connections to 16 port column ..................................... 2-WD.7
Figure 2.6 - Electrode cable connections to 18 port column ..................................... 2-WD.8
Figure 2.7 - Electrode cable connections to 20 port column ..................................... 2-WD.9
Figure 2.8 - Electrode cable connections to 22 port column ................................... 2-WD.10
Figure 2.9 - Electrode cable connections to 24 port column ................................... 2-WD.11
Figure 2.10 - Electrode cable connections to 26 port column ................................... 2-WD.12
Figure 2.11 - Electrode cable connections to 28 port column ................................... 2-WD.13
Figure 2.12 - Electrode cable connections to 30 port column ................................... 2-WD.14
Figure 2.13 - Electrode cable connections to 32 port column ................................... 2-WD.15
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.2 24685034
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.3
Figure 2.1 - Electrode cable connections to 8 port column
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.4 24685034
Figure 2.2 - Electrode cable connections to 10 port column
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.5
Figure 2.3 - Electrode cable connections to 12 port column
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.6 24685034
Figure 2.4 - Electrode cable connections to 14 port column
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.7
Figure 2.5 - Electrode cable connections to 16 port column
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.8 24685034
Figure 2.6 - Electrode cable connections to 18 port column
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.9
Figure 2.7 - Electrode cable connections to 20 port column
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.10 24685034
Figure 2.8 - Electrode cable connections to 22 port column
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.11
Figure 2.9 - Electrode cable connections to 24 port column
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.12 24685034
Figure 2.10 - Electrode cable connections to 26 port column
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.13
Figure 2.11 - Electrode cable connections to 28 port column
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.14 24685034
Figure 2.12 - Electrode cable connections to 30 port column
Hydrastep 2468CB and 2468CD Manual Wiring Diagrams for Dual Power Supply Version
24685034 2-WD.15
Figure 2.13 - Electrode cable connections to 32 port column
Wiring Diagrams for Dual Power Supply Version Hydrastep 2468CB and 2468CD Manual
2-WD.16 24685034
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-1
3a
2468 - Relay Output Board Option
Contents
Page No.
3A.1 GENERAL DESCRIPTION 3
3A.2 INSTALLATION 3
3A.2.1 STORAGE & PRE-INSTALLATION INSPECTION ................................... 3
3a.2.1.1 Storage Area ............................................................................... 3
3a.2.1.2 Pre-Installation Inspection ........................................................... 3
3A.2.2 MECHANICAL INSTALLATION ................................................................ 3
3a.2.2.1 Fitting the Nylon Spacers to the Relay Output Board ................. 4
3a.2.2.2 Mounting the Relay Output Board on to the Input Board ............ 4
3A.2.3 ELECTRICAL INSTALLATION ................................................................. 5
3a.2.3.1 PCB Interconnections ................................................................. 5
3a.2.3.2 Relay Output Connections .......................................................... 5
3A.3 RELAY BOARD CONFIGURATION 6
3A.3.1 RELAY OUTPUT BOARD ......................................................................... 7
3a.3.1.1 Configuring the Relay Output Board ........................................... 7
3a.3.1.2 Electrode/Relay Selection (Relays RL1, RL2, RL3 & RL4) -
SW1 To SW4 .............................................................................. 7
3a.3.1.3 Relay Energisation (‘In Steam’ or ‘In Water’) - SW5 ................... 8
3a.3.1.4 Electrode/Alarm Operation (RL1 Function Only) - SW6 ............. 8
3a.3.1.5 System Fault Output ................................................................... 8
3A.3.2 ALARM AND TRIPPING FACILITIES ....................................................... 9
3a.3.2.1 Philosophy ................................................................................... 9
3a.3.2.2 Relay Interconnections for Alarm/Tripping Systems ................... 9
3a.3.2.3 ‘One out of Two’ Relay Alarm System ...................................... 10
3a.3.2.4 ‘Two out of Two’ Relay Alarm System ...................................... 11
3a.3.2.5 ‘Two out of Four’ Relay Alarm System ..................................... 12
3a.3.2.6 ‘Two out of Three’ Relay Alarm System ................................... 14
3A.4 COMPONENT REPLACEMENT 15
3a.4.1 REPLACEMENT OF NYLON SPACERS ................................. 15
3a.4.2 PARTS LIST - RELAY OUTPUT BOARD 24680504 ................ 15
3A.5 SPECIFICATION 16
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-2 24685034
Illustrations
Figure 3a.1 - View of relay output board showing switch positions and output pin details . 3a-6
Tables
Table 3a.1 - Electrode selections for relays RL1 to RL4 ..................................................... 3a-7
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-3
3A.1 GENERAL DESCRIPTION
The Relay Output Board (PCB 24680504) has four relays and is mounted on top of the input
board using 3 nylon spacers. Electrical connection between the two boards is via plug and
socket (SK1 on the input board and PL1 on the relay output board).
A second relay output board may be mounted on top of the first on nylon spacers. Holes
have been drilled on all relay output boards to receive the 3 nylon spacers. The top board is
offset towards the centre of the unit improving the cable layout from the relay output boards.
The nylon spacer fixing holes and mounting holes are illustrated in Figure 3a.1 on page 3a-6.
Each of the 4 relays can be energised by any one of up to 16 electrodes, with an individual
choice of being energised when its selected electrode is in steam or is in water.
Furthermore, relay RL1 can be used to monitor an electrode state or to register an ALARM
condition. When set to register the ALARM state, the relay is energised in the ‘system
normal’ state and de-energises when an ALARM condition exists.
This option comes complete with the nylon spacers and two 8-way output sockets.
3A.2 INSTALLATION
This sub-section deals with the mechanical and electrical installation of the Relay Output
Board (PCB 24680504) option. In the rest of this chapter the ‘relay output board’ title is
shortened to ‘relay board’.
3A.2.1 STORAGE & PRE-INSTALLATION INSPECTION
3a.2.1.1 Storage Area
The storage area must be dry, dust-free and kept at a reasonable temperature. The storage
area should allow for access and inspection of all items of equipment.
3a.2.1.2 Pre-Installation Inspection
Open the option package and inspect the contents for signs of damage. Check contents for
completeness.
3A.2.2 MECHANICAL INSTALLATION
The output board is mounted directly on top of the input board. The input board is supplied
with three nylon spacers fitted. The output board is then aligned on its Berg socket/plug
interconnection (PL1/SK1) and input board-mounted spacers and pressed home on to the
spacers.
When two output boards are required to be mounted on an input board, the second output
board is mounted on three nylon spacers fitted on the first mounted output board.
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-4 24685034
3a.2.2.1 Fitting the Nylon Spacers to the Relay Output Board
The spacers fit into the holes within the white-bordered areas on the output board (see
Figure 3a.1 on page 3a-6).
1. Fit the nylon spacers into their prepared holes on
the output board and lock in position using the nylon
washer and M4 nut, see inset diagram.
2. Fit the output board on to the spacers and check for
correct alignment and adjust if necessary.
3a.2.2.2 Mounting the Relay Output Board on to the Input Board
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
This task can be performed on a mounted 2468 electronic enclosure or the enclosure can be
removed to a bench for the installation. Here it is assumed that the enclosure is in its normal
working location. The procedure for mounting the relay output board is as follows:
1. Isolate the power supply from the 2468 electronic enclosure and open the instrument
front cover.
2. If two output boards are to be fitted, make sure that the first output board to be fitted has
had its nylon spacers fitted before installation. Also ensure the first output board is fully
configured before fitting the second output board.
3. Ease the pins of the Berg plug PL1 of the output board into the Berg socket SK1 on the
input board, checking that the mounting holes on the output board (the holes which are
not contained in white bordered areas) are aligned over the fitted spacers and gently
press the output board ‘home’ until the spring-loaded spigot on each spacer is locked
firmly on to the output board.
Note: When fitting a second output board, use the same procedure described in operation 3
but refer to the components, etc., on the mounted output board.
This concludes the mechanical installation of the output board(s) and should be followed by
the electrical installation. If the latter is not to be carried out in the immediate future then the
power supply can be reconnected.
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-5
3A.2.3 ELECTRICAL INSTALLATION
This sub-section deals with the output of the states of the four relays. Two 8-way sockets
are provided with each output board through which the relay outputs are delivered to their
external destinations.
3a.2.3.1 PCB Interconnections
Signal interconnection between the input board (PCB1) and the output board (PCB4) is
direct via the SK1/PL1 12-way Berg connectors. When two output boards are fitted, the top
board’s plug PL1 engages in the lower board’s SK1.
3a.2.3.2 Relay Output Connections
The relay outputs can be taken out of the enclosure via the gland plate or along with the
other cables in suitable trunking.
Use screened cables for all connections, making sure a good annular (ring shape) connection
is made with a good quality RF cable gland. The run must be stress-free, and it is considered
good practice to twist relay pairs together.
Since the output board is mounted on top of the input board, the routing of the relay cabling
should take the same kind of formation as the electrode cabling, but separated from it as far
as practical. The cable should be arranged such that the cables do not lie across any of the
PCBs. The layout and plug pin details of the two plugs on the relay board is given in the
diagram on the right, with the relay contacts shown in their de-energised state.
When two output boards are fitted, the output terminals of the uppermost output board are
offset towards the centre of the input board.
View illustrating mounted positions of dual
relay output boards Relay output PCB
connectors
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-6 24685034
3A.3 RELAY BOARD CONFIGURATION
The 24680504 Relay Output Board has three configuration switches:
SW6: Selects Electrode or Alarm state for RL1.
SW1 - SW4: Selects individual electrode for relays RL1 to RL4.
SW5: Selects RL1 - RL4 to be energised in steam or in water.
Figure 3a.1 provides a view of the output board layout to highlight the positions of the various
configuration switches.
Figure 3a.1 - View of relay output board showing switch positions and output pin details
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-7
3A.3.1 RELAY OUTPUT BOARD
3a.3.1.1 Configuring the Relay Output Board
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Isolate the 2468 electronics enclosure from its power supplies.
2. Gain access to the relay output PCB and set the relevant switches for the required function.
3a.3.1.2 Electrode/Relay Selection (Relays RL1, RL2, RL3 & RL4) - SW1 To SW4
Four identical switches are provided on the relay board for electrode selection. Any of the
electrodes, connected to the input board on which the relay board is mounted, can be
selected as the input for any of the relays.
With one input board installed, any electrode connected to the system can be used as the
source for any of the four relays. With two input boards installed, the relay board mounted
on the input board connected to the odd numbered electrodes, accepts inputs from the odd
numbered electrodes. Similarly, the relay board mounted on the input board connected to
the even numbered electrodes, accepts inputs from even numbered electrodes. Table 3a.1
details switch selection.
Switch SW1, SW2, SW3 or SW4
Settings for RL1 to RL4 respectively Electrode Selection
Switch Contacts One Input Two Input Cards
1 2 3 4 Card Odd I/P Card Even I/P Card
On On On On 1 1 2
Off On On On 2 3 4
On Off On On 3 5 6
Off Off On On 4 7 8
On On Off On 5 9 10
Off On Off On 6 11 12
On Off Off On 7 13 14
Off Off Off On 8 15 16
On On On Off 9 17 18
Off On On Off 10 19 20
On Off On Off 11 21 22
Off Off On Off 12 23 24
On On Off Off 13 25 26
Off On Off Off 14 27 28
On Off Off Off 15 29 30
Off Off Off Off 16 31 32
Table 3a.1 - Electrode selections for relays RL1 to RL4
Example: Single Input Board: Electrode 13 selected.
Dual Input Boards: Odd input board - Electrode 25 selected
Even input board - Electrode 26 selected.
1
2
3
4
OFF
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-8 24685034
3a.3.1.3 Relay Energisation (‘In Steam’ or ‘In Water’) - SW5
This is a four-channel switch, one channel allocated per relay. The switch selects whether
the relay is energised when the selected electrode is in water or is in steam. This switch is
highlighted in Figure 3a.1 (on page 3a-6) to provide additional information on channel identity
and the switch ‘electrode state’.
3a.3.1.4 Electrode/Alarm Operation (RL1 Function Only) - SW6
Relay 1 can be configured to receive either an electrode input or it can be used as the
‘system fault’ relay (see Figure 3a.1 on page 3a-6). When configured as the system fault
relay, the normal state of the relay is energised, a fault state will de-energise the relay.
See the next section for contact output details.
3a.3.1.5 System Fault Output
Relay 1 on each relay board can be configured to be used as a system fault relay by setting
SW6. When used as a system fault relay the normal state of the relay is energised and a
fault state will de-energise the relay.
The relay will only output faults detected by the input board onto which it is installed. With a
dual power supply Hydrastep unit, this means it is necessary to used two relay boards (one
on each input board) to create a system fault output.
(Relays shown in de-energised state)
(Switch SW6 set for fault signal operation)
Alarm off when contacts closed
Even fault relay
(LH input board)
RL 1
1
4
3
2
To alarm annunciator
RL 1
1
4
3
2
PL 2 PL 2
Odd fault relay
(RH input board)
Alarm off when contacts open
Even fault relay
(LH input board)
RL 1
1
4
3
2
To alarm annunciator
RL 1
1
4
3
2
PL 2 PL 2
Odd fault relay
(RH input board)
Note: Systems with a local display have an opto-isolated system fault available from
the display board.
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-9
3A.3.2 ALARM AND TRIPPING FACILITIES
The relay boards provide high and low water level alarm and trip facilities for the 2468
Hydrastep system. Four to eight relays can be made available for each input board fitted.
3a.3.2.1 Philosophy
A requirement in regulations concerning steam raising plant is the provision of an automatic
low water level shut-down or trip device. In the 2468 Hydrastep the relay output board
provides the required output signals for such devices.
In practical applications of shut-down systems two factors must be considered, the
consequences of spurious trips and the non-availability of a trip when required, due to
protection system faults.
The following relay output circuits are specific to the 2468 Hydrastep Electronic Gauging
Systems.
3a.3.2.2 Relay Interconnections for Alarm/Tripping Systems
It is necessary to open the Hydrastep 2468 Electronic Enclosure to carry out any wiring,
therefore care must be taken when working inside the unit.
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Note: Before any relay interconnections are made it is necessary to fulfil any safety
regulations governing the plant shutdown procedures.
Since one input board receive inputs from the odd numbered electrodes and the other input
board receives inputs from the even numbered electrodes, interconnections between odd and
even relay boards will be required.
The following are examples of relay configurations used.
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-10 24685034
3a.3.2.3 ‘One out of Two’ Relay Alarm System
Either of the relays involved can cause an alarm when their assigned electrode registers an
alarm condition. The alarm condition is selected by switch SW5 to provide relay energisation
in water EW or energisation in steam ES.
Case A - Relays normally energised, de-energise either one to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Case B - Relays normally de-energised, energise either one to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-11
3a.3.2.4 ‘Two out of Two’ Relay Alarm System
This system requires both relays to operate to cause an alarm when their assigned
electrodes register an alarm condition.
Case A - Relays normally energised, de-energise both to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Case B - Relays normally de-energised, energise both to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-12 24685034
3a.3.2.5 ‘Two out of Four’ Relay Alarm System
In the following diagrams (5A & 5B) indicate the electrode channel selected for
each relay. A fully functioning system (NO FAULTS) will perform a low level trip at electrode
level 3. For a high level trip, using electrode channels 11, 12, 9 and 10 respectively and
switch SW5 set for ES, a healthy system would trip at level 10.
Case A - Relays normally energised, de-energise one in each pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts open
Case B - Relays normally energised, de-energise one pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts open
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-13
In the following diagrams (6A & 6B) indicate the electrode channel selected for
each relay. A fully functioning system (NO FAULTS) will perform a low level trip at electrode
level 2. For a high level trip, using electrode channels 9,10, 11 and 12 respectively and
switch SW5 set for ES, a healthy system would trip at level 11.
Case A - Relays normally energised, de-energise one in each pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts closed
Case B - Relays normally de-energised, energise one in each pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board) Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts open
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-14 24685034
3a.3.2.6 ‘Two out of Three’ Relay Alarm System
In the following diagrams (7A & 7B) indicate the electrode channel selected for each
relay. A fully functioning system (NO FAULTS) will cause a low level trip at electrode level 2.
Using high-level electrode channels and SW5 set to ES, the circuit can perform a high level trip.
Note: Inputs from electrodes 1 & 2 are applied to two separate relays on their respective boards.
Case A - Relays normally energised, de-energise two to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
32
2
Alarm off when contacts closed
RL 3
PL 3
1
1
1
4
3
2
Case B - Relays normally de-energised, energise two to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
32
2
Alarm off when contacts open
RL 3
PL 3
1
1
1
4
3
2
Hydrastep 2468CB and 2468CD Manual Relay Output Board Option
24685034 3a-15
3A.4 COMPONENT REPLACEMENT
The relay board contains no replaceable circuit components, failure of the board requires
replacement of the entire board. The only component that can be replaced is the nylon spacer.
3A.4.1 REPLACEMENT OF NYLON SPACERS
The replacement of nylon spacers fitted to the output board requires access to the non-
component side of the PCB.
Note: Spacers will only be fitted on the output board if a second output board is to be fitted
or has been fitted.
The spacers are secured in their holes by nut and nylon washer. To carry out a spacer
replacement, the output board has to be removed from the input board. The procedure
adopted is:
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Isolate the 2468 electronic enclosure from the power supply.
2. Gain access to the PCBs and undo sufficient connections for the removal of the output
board containing the defective spacer.
3. Remove the output board(s) by applying pressure
to the upper spring-loaded spigots and easing the
output board off its spacers and out of its Berg
plug/socket connection.
4. Undo the nut and washer securing the faulty
spacer and extract it from its hole, see inset
diagram.
5. Fit the new spacer in position, align correctly on
the board and secure firmly using the M4 nut and
nylon washer.
6. Refit the PCB(s) into the enclosure, re-connect
the PCB(s) as required and close the enclosure
cover. Re-apply the power.
3A.4.2 PARTS LIST - RELAY OUTPUT BOARD 24680504
The following list items are available as spare parts:
Item Description Mobrey Part
Number Item Description Mobrey Part
Number
Electrical:
Relay PCB assembly:
Socket 5K2 free (8-way)
Socket 5k3 free (8-way)
24680504C
351508100
351503100
Mechanical:
Spacer, nylon 15.9 LG
Washer, nylon
Nut, M4
412012080
411999910
410031020
Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3a-16 24685034
3A.5 SPECIFICATION
Outputs: 4 x Alarm/Trip Relays
Relay Contact Rating: ac dc
Maximum voltage: 250V 125V
Maximum current: 8A 8A
Maximum switching power: 1500VA 240W ( 30V)
65W ( 60V)
25W ( 125V)
For type nA safety: 100mA at 30Vdc
Maximum initial contact resistance: 30m
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-1
3b
Delay Relay Output Board Option
Contents
Page No.
3B.1 GENERAL DESCRIPTION ........................................................................................ 3
3B.2 INSTALLATION ......................................................................................................... 3
3B.2.1 STORAGE & PRE-INSTALLATION INSPECTION ................................... 3
3b.2.1.1 Storage Area ............................................................................... 3
3b.2.1.2 Pre-Installation Inspection ........................................................... 3
3B.2.2 MECHANICAL INSTALLATION ................................................................ 4
3b.2.2.1 Fitting the Nylon Spacers to the Delay Relay Output Board ....... 4
3b.2.2.2 Mounting the Delay Relay Output Board on to the Input Board . 4
3B.2.3 ELECTRICAL INSTALLATION ................................................................. 5
3b.2.3.1 PCB Interconnections ................................................................. 5
3b.2.3.2 Relay Output Connections .......................................................... 5
3B.3 DELAY RELAY BOARD CONFIGURATION ............................................................ 6
3B.3.1 DELAY RELAY OUTPUT BOARD ............................................................ 7
3b.3.1.1 Configuring the Delay Relay Output Board ................................. 7
3b.3.1.2 Electrode/Relay Selection (Relays RL1, RL2, RL3 & RL4) - SW1
to SW4 ........................................................................................ 7
3b.3.1.3 Relay Energisation (‘In Steam’ or ‘In Water’) - SW5 ................... 8
3b.3.1.4 Electrode/Alarm Operation (RL1 function only) - SW6 ............... 8
3b.3.1.5 System Fault Output ................................................................... 8
3b.3.1.6 Delay Circuit Configuration ......................................................... 9
3b.3.1.7 Configuring the Delay Circuit Split Pads ................................... 10
3B.3.2 ALARM AND TRIPPING FACILITIES ..................................................... 11
3b.3.2.1 Philosophy ................................................................................. 11
3b.3.2.2 Relay Interconnections for Alarm/Tripping Systems ................. 11
3b.3.2.3 ‘One out of Two’ Relay Alarm System ...................................... 12
3b.3.2.4 ‘Two out of Two’ Relay Alarm System ...................................... 13
3b.3.2.5 ‘Two out of Four’ Relay Alarm System ..................................... 14
3b.3.2.6 ‘Two out of Four’ Relay Alarm System (contd.) ........................ 15
3b.3.2.7 ‘Two out of Three’ Relay Alarm System ................................... 16
3B.4 COMPONENT REPLACEMENT ............................................................................. 17
3B.4.1 REPLACEMENT OF NYLON SPACERS ................................................ 17
3B.4.2 PARTS LIST - DELAY RELAY OUTPUT BOARD 24680509 ................ 17
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-2 24685034
3B.5 SPECIFICATION ..................................................................................................... 18
Illustrations
Figure 3b.1 - View of relay output board showing switch positions and output pin
details ............................................................................................................ 3b-6
Figure 3b.2 - View of delay relay output board showing split pad positions ..................... 3b-10
Tables
Table 3b.1 - Electrode selections for relays RL1 to RL4 .................................................. 3b-7
Table 3b.2 - Split pad functions on relay delay circuits .................................................... 3b-9
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-3
3B.1 GENERAL DESCRIPTION
The Delay Relay Output Board (PCB 24680509) is mounted on top of the input board using 3
nylon spacers. Electrical connection between the two boards is via plug and socket (SK1 on
the input board and PL1 on the delay relay output board).
A second delay relay output board may be mounted on top of the first on nylon spacers.
Holes have been drilled on all delay relay output boards to receive the 3 nylon spacers. The
top output board is offset towards the centre of the unit improving the cable layout from the
delay relay output boards. The nylon spacer fixing holes and mounting holes are illustrated
in Figure 3b.1 (on page 3b-6).
Each of the four delay relays can be energised by any one of up to 16 electrodes, with an
individual choice of being energised when its selected electrode is in steam or is in water.
Furthermore, relay RL1 can be used to monitor an electrode state or to register an ALARM
condition. When set to register the ALARM state, the relay is energised in the ‘system
normal’ state and de-energises when an ALARM condition exists.
Each relay channel also contains a delay circuit where set delays of between 0 and 23
seconds can be provided using one of four split pad links. Provision is also made by split
pad links, to bypass each delay circuit. The split pad linkage is fully covered in section 3b.3
of this chapter.
This option comes complete with the nylon spacers and two 8-way output sockets.
3B.2 INSTALLATION
This sub-section deals with the mechanical and electrical installation of the Delay Relay
Output Board (PCB 24680504) option. In the rest of this chapter the ‘delay relay output
board’ title is shortened to ‘output board’.
3B.2.1 STORAGE & PRE-INSTALLATION INSPECTION
3b.2.1.1 Storage Area
The storage area must be dry, dust-free and kept at a reasonable temperature. The storage
area should allow for access and inspection of all items of equipment.
3b.2.1.2 Pre-Installation Inspection
Open the option package and inspect the contents for signs of damage. Check contents for
completeness.
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-4 24685034
3B.2.2 MECHANICAL INSTALLATION
The output board is mounted directly on top of the input board. The input board is supplied
with three nylon spacers fitted. The output board is then aligned on its Berg socket/plug
interconnection (PL1/SK1) and input board-mounted spacers and pressed home on to the
spacers.
When two output boards are required to be mounted on an input board, the second output
board is mounted on three nylon spacers fitted on the first mounted output board.
3b.2.2.1 Fitting the Nylon Spacers to the Delay Relay Output Board
The spacers fit into the holes within the white-bordered areas on the output board (see
Figure 3b.1 on page 3b-6).
1. Fit the nylon spacers into their prepared holes on the
output board and lock in position using the nylon
washer and M4 nut, see inset diagram.
2. Fit the output board on to the spacers and check for
correct alignment and adjust if necessary.
3b.2.2.2 Mounting the Delay Relay Output Board on to the Input Board
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
This task can be performed on a mounted 2468 electronic enclosure or the enclosure can be
removed to a bench for the installation. Here it is assumed that the enclosure is in its normal
working location. The procedure for mounting the delay relay output board is as follows:
1. Isolate the power supply from the 2468 electronic enclosure and open the instrument front
cover.
2. If two output boards are to be fitted, make sure that the first output board to be fitted has
had its nylon spacers fitted before installation. Also ensure the first output board is fully
configured before fitting the second output board.
3. Ease the pins of the Berg plug PL1 of the output board into the Berg socket SK1 on the
input board, checking that the mounting holes on the output board (the holes which are
not contained in white bordered areas) are aligned over the fitted spacers and gently
press the output board ‘home’ until the spring-loaded spigot on each spacer is locked
firmly on to the output board.
Note: When fitting a second output board, use the same procedure described in operation
3 but refer to the components, etc., on the mounted output board.
This concludes the mechanical installation of the output board(s) and should be followed by
the electrical installation. If the latter is not to be carried out in the immediate future then the
power supply can be reconnected.
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-5
3B.2.3 ELECTRICAL INSTALLATION
This sub-section deals with the output of the states of the four relays. Two 8-way sockets are
provided with each output board through which the relay outputs are delivered to their
external destinations.
3b.2.3.1 PCB Interconnections
Signal interconnection between the input board (PCB1) and the output board (PCB 9) is
direct via the SK1/PL1 12-way Berg connectors. When two output boards are fitted, the top
board’s plug PL1 engages in the lower board’s SK1.
3b.2.3.2 Relay Output Connections
The relay outputs can be taken out of the enclosure via the gland plate (if used) or along with
the other cables in suitable trunking.
Use screened cables for all connections, making sure a good annular (ring shape) connection
is made with a good quality RF cable gland. The run must be stress-free, and it is considered
good practice to twist relay pairs together.
Since the output board is mounted on top of the input board, the routing of the relay cabling
should take the same kind of formation as the electrode cabling, but separated from it as far
as practical. The cable should be arranged such that the cables do not lie across any of the
PCBs. The layout and plug pin details of the two plugs on the relay board is given in the
diagram on the right, with the relay contacts shown in their de-energised state.
When two output boards are fitted, the output terminals of the uppermost output board are
offset towards the centre of the input board.
View illustrating mounted positions of dual
delay relay output boards Relay output PCB
connectors
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-6 24685034
3B.3 DELAY RELAY BOARD CONFIGURATION
The 24680509 Delay Relay Output Board has three configuration switches and twenty split
pad links for delay time selection. The switches are:
SW6: Selects Electrode or Alarm state for RL1.
SW1 - SW4: Selects individual electrode for relays RL1 to RL4.
SW5: Selects RL1 - RL4 to be energised in steam or in water.
Figure 3b.1 provides a view of the output board layout to highlight the positions of the various
configuration switches.
Figure 3b.1 - View of relay output board showing switch positions and output pin details
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-7
3B.3.1 DELAY RELAY OUTPUT BOARD
3b.3.1.1 Configuring the Delay Relay Output Board
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Isolate the 2468 electronics enclosure from its power supplies.
2. Gain access to the delay relay output PCB and set the relevant switches for the required
function.
3b.3.1.2 Electrode/Relay Selection (Relays RL1, RL2, RL3 & RL4) - SW1 to SW4
Four identical switches are provided, one for each relay (but see SW6) each having four sets
of contacts. This allows coded selection for one of 16 electrodes for each switch and
therefore for each relay in the case of the single input card. When dual input cards are fitted,
odd numbered electrodes feed into one input card with the even numbered electrodes being
fed into the other input card. Each input card then offers any mounted relay output card the
choice from its electrode inputs, with the resultant selectivity as shown in Table 3b.1.
Switch SW1, 5W2, 5W3 or 5W4 Settings for
RL1 to RL4 respectively Electrode Selection
Switch Contacts One Input Two Input Cards
1 2 3 4 Card Odd I/P Card Even I/P Card
On On On On 1 1 2
Off On On On 2 3 4
On Off On On 3 5 6
Off Off On On 4 7 8
On On Off On 5 9 10
Off On Off On 6 Ii 12
On Off Off On 7 13 14
Off Off Off On 8 15 16
On On On Off 9 17 18
Off On On Off 10 19 20
On Off On Off 11 21 22
Off Off On Off 12 23 24
On On Off Off 13 25 26
Off On Off Off 14 27 28
On Off Off Off 15 29 30
Off Off Off Off 16 31 32
Table 3b.1 - Electrode selections for relays RL1 to RL4
Example: Single Input Board - Electrode 13 selected.
Dual Input Boards: Odd input board - Electrode 25 selected
Even input board - Electrode 26 selected.
1
2
3
4
OFF
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-8 24685034
3b.3.1.3 Relay Energisation (‘In Steam’ or ‘In Water’) - SW5
This is a four-channel switch, one channel allocated per relay. The choice presented by each
channel switch is whether the relay is energised when the particular electrode is in water or
energised when that electrode is in steam. This switch is highlighted in Figure 3b.1 (on page
3b-6) to provide additional information on channel identity and the switch ‘electrode state’.
3b.3.1.4 Electrode/Alarm Operation (RL1 function only) - SW6
Relay 1 can be configured to receive either an electrode input or it can be used as the ‘system
fault’ relay. The two positions are detailed in Figure 3b.1 (on page 3b-6). When configured as
the system fault relay, the normal (non-fault) state of the relay is energised.
The system fault output connections are shown in the next section.
3b.3.1.5 System Fault Output
Relay 1 on each delay relay board can be configured to be a system fault relay by setting
SW6. When used as a system fault relay the normal state of the relay is energised and a
fault state will de-energise the relay.
The relay will only output faults detected by the input board onto which it is installed. With a
dual power supply Hydrastep unit, this means it is necessary to used two delay relay boards
(one on each input board) to create a system fault output.
(Relays shown in de-energised state)
(Switch SW6 set for fault signal operation)
Alarm off when contacts closed
Even fault relay
(LH input board)
RL 1
1
4
3
2
To alarm annunciator
RL 1
1
4
3
2
PL 2 PL 2
Odd fault relay
(RH input board)
Alarm off when contacts open
Even fault relay
(LH input board)
RL 1
1
4
3
2
To alarm annunciator
RL 1
1
4
3
2
PL 2 PL 2
Odd fault relay
(RH input board)
Note: Systems with a local display have an opto-isolated system fault available from the
display board.
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-9
3b.3.1.6 Delay Circuit Configuration
By means of split pad links incorporated in each of the relay delay circuits, delays can be
introduced or bypassed and the following delays are made available (see also Figure 3b.2):
Table 3b.2 - Split pad functions on relay delay circuits
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-10 24685034
3b.3.1.7 Configuring the Delay Circuit Split Pads
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Isolate the 2468 electronics enclosure from its power supplies.
2. Split pad bridging may be carried out in-situ, however it may be easier to remove the
board from the unit. Gain access to the delay relay output PCB and bridge the required
split pads (see Table 3b.2 and Figure 3b.2) with solder, ensuring that the remaining split
pads are open-circuit and clean.
3. Note: When two output boards are fitted, the upper board will have to be removed
temporarily to give access to the split pads of the lower output board.
4. Carry out any necessary re-assembly on the output board(s) and test that the required
delay on the relay operations is being achieved.
5. If no further work is required inside the enclosure, close and secure the enclosure lid.
Figure 3b.2 - View of delay relay output board showing split pad positions
Note: The following split pads
must be set as follows:
For Delayed Operation of the
Nominated Relay:
RL1 SP21 bridged with solder
SP15 open-circuited
RL2 SP22 bridged with solder
SP20 open-circuited
RL3 SP23 bridged with solder
SP1 open-circuited
RL4 SP24 bridged with solder
SP6 open-circuited
For No Delayed Operation of the
Nominated Relay:
RL1 SP15 bridged with solder
SP21 open-circuited
RL2 SP20 bridged with solder
SP22 open-circuited
RL3 SP1 bridged with solder
SP23 open-circuited
RL4 SP6 bridged with solder
SP24 open-circuited
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-11
3B.3.2 ALARM AND TRIPPING FACILITIES
The relay boards provide high and low water level alarm and trip facilities for the 2468
Hydrastep system. Four to eight relays can be made available for each input board fitted.
3b.3.2.1 Philosophy
A requirement in regulations concerning steam raising plant is the provision of an automatic
low water level shut-down or trip device. In the 2468 Hydrastep the relay output board
provides the required output signals for such devices.
In practical applications of shut-down systems two factors must be considered, the
consequences of spurious trips and the non-availability of a trip when required, due to
protection system faults.
The following relay output circuits are specific to the 2468 Hydrastep Level Indicator
versions.
3b.3.2.2 Relay Interconnections for Alarm/Tripping Systems
It is necessary to open the Hydrastep 2468 Electronic Enclosure to carry out any wiring,
therefore care must be taken when working inside the unit.
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Note: Before any relay interconnections are made it is necessary to fulfil any safety
regulations governing the plant shutdown procedures.
Since one input board receives inputs from the odd numbered electrodes and the other input
board receives inputs from the even numbered electrodes, interconnections between odd
and even relay boards will be required.
The following are examples of relay configurations used.
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-12 24685034
3b.3.2.3 ‘One out of Two’ Relay Alarm System
Either of the relays involved can cause an alarm when their assigned electrode registers an
alarm condition. The alarm condition is selected by switch SW5 to provide relay energisation
in water EW or energisation in steam ES.
Case A - Relays normally energised, de-energise either one to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Case B - Relays normally de-energised, energise either one to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-13
3b.3.2.4 ‘Two out of Two’ Relay Alarm System
This system requires both relays to operate to cause an alarm when their assigned
electrodes register an alarm condition.
Case A - Relays normally energised, de-energise both to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Case B - Relays normally de-energised, energise both to trip
(Relays shown in de-energised state)
(Switch SW5 is set to ES for low level alarms and set to EW for high level alarms)
Alarm off when contacts closed
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
Alarm off when contacts open
Even electrodes
(LH input board)
RL 1
To alarm annunciator
RL 1
Odd electrodes
(RH input board)
1
4
3
2
1
4
3
2
PL 2
4
2
1
3
PL 2
1
4
3
2
PL 2
PL 2
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-14 24685034
3b.3.2.5 ‘Two out of Four’ Relay Alarm System
In the following diagrams (5A & 5B) indicate the electrode channel selected for
each relay. A fully functioning system (NO FAULTS) will perform a low level trip at electrode
level 3. For a high level trip, using electrode channels 11, 12, 9 and 10 respectively and
switch SW5 set for ES, a healthy system would trip at level 10.
Case A - Relays normally energised, de-energise one in each pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts open
Case B - Relays normally energised, de-energise one pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts open
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-15
3b.3.2.6 ‘Two out of Four’ Relay Alarm System (contd.)
In the following diagrams (6A & 6B) indicate the electrode channel selected for
each relay. A fully functioning system (NO FAULTS) will perform a low level trip at electrode
level 2. For a high level trip, using electrode channels 9, 10, 11 and 12 respectively and
switch SW5 set for ES, a healthy system would trip at level 11.
Case A - Relays normally energised, de-energise one in each pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts closed
Case B - Relays normally de-energised, energise one in each pair to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board) Even electrodes
(LH input board)
3
1
4
2
Alarm off when contacts open
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-16 24685034
3b.3.2.7 ‘Two out of Three’ Relay Alarm System
In the following diagrams (7A & 7B) indicate the electrode channel selected for each
relay. A fully functioning system (NO FAULTS) will cause a low level trip at electrode level 2.
Using high-level electrode channels and SW5 set to ES, the circuit can perform a high level trip.
Note: Inputs from electrodes 1 & 2 are applied to two separate relays on their respective boards.
Case A - Relays normally energised, de-energise two to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
32
2
Alarm off when contacts closed
RL 3
PL 3
1
1
1
4
3
2
Case B - Relays normally energised, de-energise two to trip
(Relays shown in de-energised state)
1
4
3
2
5
8
7
6
(Switch SW5 is set to EW for low-level alarms and set to ES for high-level alarms)
1
4
3
2
5
8
7
6
To alarm
annunciator
or tripping
device
RL 1
RL 2
RL 2
RL 1 PL 2 PL 2
Odd electrodes
(RH input board)
Even electrodes
(LH input board)
32
2
Alarm off when contacts open
RL 3
PL 3
1
1
1
4
3
2
Hydrastep 2468CB and 2468CD Manual Delay Relay Output Board Option
24685034 3b-17
3B.4 COMPONENT REPLACEMENT
The delay relay board contains no replaceable circuit components, failure of the board
requires replacement of the entire board. The only component that can be replaced is the
nylon spacers.
3B.4.1 REPLACEMENT OF NYLON SPACERS
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
The replacement of nylon spacers fitted to the output board requires access to the non-
component side of the PCB.
Note: Spacers will only be fitted on the output board if a second output board is to be fitted
or has been fitted.
The spacers are secured in their holes by nut and nylon washer. To carry out a spacer
replacement, the output board has to be removed from the input board. The procedure
adopted is:
1. Isolate the 2468 electronic enclosure from the power supply.
2. Gain access to the PCBs and undo sufficient connections for the removal of the output
board containing the defective spacer.
3. Remove the output board(s) by applying pressure
to the upper spring-loaded spigots and easing the
output board off its spacers a out of its Berg
plug/socket connection.
4. Undo the nut and washer securing the faulty
spacer and extract it from its hole, see inset
diagram.
5. Fit the new spacer in position, align correctly on
the board and secure firmly using the M4 nut and
nylon washer.
6. Refit the PCB(s) into the enclosure, re-connect
the PCB(s) as required and close the enclosure
cover. Re-apply power if required.
3B.4.2 PARTS LIST - DELAY RELAY OUTPUT BOARD 24680509
The following list items are available as spare parts:
Item Description Mobrey Part
Number Item Description Mobrey Part
Number
Electrical:
Delay relay PCB assembly:
Socket 5K2 free (8-way)
Socket 5K3 free (8-way)
24680509B
351508100
351503100
Mechanical:
Spacer, nylon 15.9 LG
Washer, nylon
Nut, M4
412012080
411999910
410031020
Delay Relay Output Board Option Hydrastep 2468CB and 2468CD Manual
3b-18 24685034
3B.5 SPECIFICATION
Outputs: 4 x Alarm/Trip Relays
Relay Contact Rating: ac dc
Maximum voltage: 250V 125V
Maximum current: 8A 8A
Maximum switching power: 1500VA 240W ( 30V)
65W ( 60V)
25W ( 125V)
For type nA safety: 100mA at 30Vdc
Maximum initial contact resistance: 30m
Time Delay: Disabled or 0.8 ± 0.8s to 24.2s ± 0.8s
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-1
3c
2468 Opto-isolated Output Board Option
Contents
Page No.
3C.1 GENERAL DESCRIPTION ........................................................................................ 3
3C.2 INSTALLATION ......................................................................................................... 3
3C.2.1 STORAGE & PRE-INSTALLATION INSPECTION ................................... 3
3c.2.1.1 Storage Area ............................................................................... 3
3c.2.1.2 Pre-installation Inspection ........................................................... 3
3C.2.2 MECHANICAL INSTALLATION ................................................................ 4
3c.2.2.1 Fitting Nylon Spacers to the Opto-Isolated Output Board .......... 4
3c.2.2.2 Mounting the Opto-Isolated Output Board on to the Input Board 4
3C.2.3 ELECTRICAL INSTALLATION ................................................................. 5
3c.2.3.1 PCB Interconnections ................................................................. 5
3c.2.3.2 Opto-Isolated Output Connections.............................................. 5
3C.3 OPTO-ISOLATED OUTPUT BOARD CONFIGURATION........................................ 6
3C.3.1 CONFIGURING THE OPTO-ISOLATED OUTPUT BOARD ..................... 7
3c.3.1.1 Electrode/Opto-Output Selection (Opto-1, Opto-2, Opto-3 &
Opto-4 Outputs) - SW1 to SW4 .................................................. 7
3c.3.1.2 Electrode/Alarm Operation (output 1 function only) - SW6 ......... 8
3c.3.1.3 Opto-Isolated Output Activation (‘In Steam’ or ‘In Water’) -
SW5 ............................................................................................ 8
3c.3.1.4 System Fault Output ................................................................... 8
3C.3.2 ALARM AND TRIPPING FACILITIES ....................................................... 9
3c.3.2.1 Philosophy ................................................................................... 9
3c.3.2.2 Opto-Output Interconnections for Alarm/Tripping Systems ........ 9
3c.3.2.3 ‘One out of Two’ Opto-output Alarm System ............................ 10
3c.3.2.4 ‘Two out of Two’ Opto-output Alarm System ............................ 11
3c.3.2.5 ‘Two out of Four’ Opto-output Alarm System ............................ 12
3c.3.2.6 ‘Two out of Three’ Opto-output Alarm System .......................... 13
3C.4 COMPONENT REPLACEMENT ............................................................................. 14
3C.4.1 REPLACEMENT OF NYLON SPACERS ................................................ 14
3C.4.2 PARTS LIST - OPTO-ISOLATED OUTPUT BOARD 24680505 ............ 14
3C.5 SPECIFICATION ..................................................................................................... 15
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-2 24685034
Illustrations
Figure 3c.1 - View of opto-isolated board showing switch positions and output
pin details ...................................................................................................... 3c-6
Tables
Table 3c.1 - Electrode selections for opto-isolated outputs Opto 1 to Opto 4 .................. 3c-7
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-3
3C.1 GENERAL DESCRIPTION
The Opto-isolated Output Board (PCB 24680505) has four opto-isolated outputs and is
mounted on top of the input board using 3 nylon spacers. Electrical connection between the
two boards is via a plug and a socket (SK1 on the input board and PL1 on the opto-isolated
output board).
A second opto-isolated output board may be mounted on top of the first on spacers. Holes
have been drilled on all opto-isolated output boards to receive the 3 nylon spacers. The top
output board is offset towards the centre of the unit improving the cable layout from the
opto-isolated output boards. The spacer fixing holes and mounting holes are illustrated in
Figure 3c.1 (on page 3c-6).
Note: The term energised is used to describe the ON (low resistance) state of the opto-
isolated output.
Each of the opto-isolated outputs can be energised by any one of up to 16 electrodes, with
an individual choice of being energised when its selected electrode is in steam or is in
water. Furthermore, opto-isolated output 1 can be used to monitor an electrode state or to
register an ALARM condition. When set to register the ALARM state, the opto-isolated
output is energised in the ‘system normal’ state and de-energised when an ALARM
condition exists.
This option comes complete with the nylon spacers and two 8-way output sockets.
3C.2 INSTALLATION
This sub-section deals with the mechanical and electrical installation of the Opto-isolated
Output Board (PCB 24680505) option. In the rest of this chapter the ‘opto-isolated output
board’ title is shortened to ‘output board’.
3C.2.1 STORAGE & PRE-INSTALLATION INSPECTION
3c.2.1.1 Storage Area
The storage area must be dry, dust-free and kept at a reasonable temperature. The storage
area should allow for access and inspection of all items of equipment.
3c.2.1.2 Pre-installation Inspection
Open the option package and inspect the contents for signs of damage. Check contents for
completeness.
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-4 24685034
3C.2.2 MECHANICAL INSTALLATION
The output board is mounted directly on top of the input board. The input board is supplied
with three nylon spacers fitted. The output board is then aligned on its Berg socket/plug
interconnection (PL1/SK1) and input board-mounted spacers and pressed home on to the
spacers.
3c.2.2.1 Fitting Nylon Spacers to the Opto-Isolated Output Board
The spacers lit into the holes within the white-bordered areas on the output board (see
Figure 3c.1 on page 3c-6).
1. Fit the nylon spacers into their prepared holes on the
output board and lock in position using the nylon
washer and M4 nut, see inset diagram.
2. Fit the output board on to the spacers and check for
correct alignment and adjust if necessary.
3c.2.2.2 Mounting the Opto-Isolated Output Board on to the Input Board
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
This task can be performed on a mounted 2468 electronic enclosure or the enclosure can be
removed to a bench for the installation. Here it is assumed that the enclosure is in its normal
working location. The procedure for mounting the output board is as follows:
1. Isolate the power supply from the 2468 electronic enclosure and open the instrument front
cover.
2. If two output boards are to be fitted, make sure that the first output board to be fitted has
had its nylon spacers fitted before installation. Also ensure the first output board is fully
configured before fitting the second output board.
3. Ease the pins of the Berg plug PL1 of the output board into the Berg socket SK1 on the
input board, checking that the mounting holes on the output board (the holes which are
not contained in white bordered areas) are aligned over the fitted spacers and gently
press the output board ‘home’ until the spring-loaded spigot on each spacer is locked
firmly on to the output board.
Note: When fitting a second output board, use the same procedure described in operation 3
but refer to the components, etc., on the mounted output board.
This concludes the mechanical installation of the output board(s) and should be followed by
the electrical installation, If the latter is not to be carried out in the immediate future then the
power supply can be reconnected.
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-5
3C.2.3 ELECTRICAL INSTALLATION
3c.2.3.1 PCB Interconnections
Signal interconnection between the input board (PCB 1) and the output board (PCB 5) is
direct via the SK1/PL1 12-way Berg connectors. Similarly, interconnection between the dual-
mounted output boards uses the same type connectors but the top board’s plug PL1
engages in the first output board’s socket SK1.
This sub-section deals with the four opto-isolated outputs. Two 8-way sockets are provided
with each output board through which the opto-isolated outputs are presented to their
external destinations via transistors TRs 2, 4, 6 and 8.
3c.2.3.2 Opto-Isolated Output Connections
The opto-isolated output states can be taken out of the enclosure via the gland plate (if used)
or along with the other cables in suitable trunking. One or more cables can be used at the
discretion of the user, however the cables must be screened and the screens terminated at
the gland plate.
Since the output board is mounted on top of the input board, the routing of the relay cabling
should take the same kind of formation as the electrode cabling, arranged such that the
cables do not lie across the PCBs. The layout and plug pin details of the two affected plugs
on the output board is given in the diagram on the right, with the required opto-coupler output
terminal polarities shown.
When two output boards are fitted, the output terminals of the uppermost output board are
offset towards the centre of the input board.
View illustrating mounting positions of dual
opto-isolated boards Opto-isolated output PCB
connectors
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-6 24685034
3C.3 OPTO-ISOLATED OUTPUT BOARD CONFIGURATION
The 24680505 Opto-isolated Output Board has three configuration switches:
SW6: Selects Electrode or Alarm state for Opto-output 1.
SW1 - SW4: Selects individual electrode for opto-outputs I to 4.
SW5: Selects Opto-outputs 1 - 4 to be energised when electrodes in
steam or in water.
Figure 3c.1 provides a view of the output board layout to highlight the positions of the various
configuration switches.
Figure 3c.1 - View of opto-isolated board showing switch positions and output pin details
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-7
3C.3.1 CONFIGURING THE OPTO-ISOLATED OUTPUT BOARD
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Gain access to the printed circuit board assemblies inside the Hydrastep 2468 enclosure as
follows:
1. Isolate the 2468 electronics enclosure from its power supplies.
2. Gain access to the output PCB and set the relevant switches for the required function.
3c.3.1.1 Electrode/Opto-Output Selection (Opto-1, Opto-2, Opto-3 & Opto-4 Outputs) - SW1 to SW4
Four identical switches are provided, one for each output (but see SW6) each having four
sets of contacts. This allows coded selection of any one of 16 electrodes for each switch in
the case of the single input card. When dual input cards are fitted, odd numbered electrodes
feed into one input card with the even numbered electrodes being fed into the other input
card. Each input card then offers any mounted output card the choice from its electrode
inputs, with the resultant selectivity as shown in Table 3c.1.
Switch SW1, SW2, SW3 or SW4 Settings for
Opto 1 to Opto 4 respectively Electrode Selection
Switch Contacts One Input Two Input Cards
1 2 3 4 Card Odd I/P Card Even I/P Card
On On On On 1 1 2
Off On On On 2 3 4
On Off On On 3 5 6
Off Off On On 4 7 8
On On Off On 5 9 10
Off On Off On 6 11 12
On Off Off On 7 13 14
Off Off Off On 8 15 16
On On On Off 9 17 18
Off On On Off 10 19 20
On Off On Off 11 21 22
Off Off On Off 12 23 24
On On Off Off 13 25 26
Off On Off Off 14 27 28
On Off Off Off 15 29 30
Off Off Off Off 16 31 32
Table 3c.1 - Electrode selections for opto-isolated outputs Opto 1 to Opto 4
Example: Single Input Board - Electrode 13 selected.
Dual Input Boards: Odd input board - Electrode 25 selected
Even input board - Electrode 26 selected.
1
2
3
4
OFF
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-8 24685034
3c.3.1.2 Electrode/Alarm Operation (output 1 function only) - SW6
Opto-isolated output from TR2 can be configured to receive either an electrode input or it
can be used as the ‘system fault’ output. The two positions are detailed in Figure 3c.1 (on
page 3c-6). When configured as the system fault output, the opto-isolated output is
energised (low resistance) in the normal (non-fault) state and is de-energised (high
resistance) for a fault condition.
The system fault output connections are shown in the next section.
3c.3.1.3 Opto-Isolated Output Activation (‘In Steam’ or ‘In Water’) - SW5
SW5 is a four-channel switch, one channel allocated per opto-isolated output. The choice
presented by each channel switch is whether the output device is energised (low resistance)
when the particular electrode is in water (W) or when that electrode is in steam (S). Switch
SW5 is highlighted in Figure 3c.1 (on page 3c-6) to provide additional information on channel
identity and the switch ‘electrode state’.
3c.3.1.4 System Fault Output
Opto 1 on each opto-isolated board can be configured to be a system fault opto-isolated
output by setting SW6. When used as a system fault opto-isolated output the normal state
of Opto 1 is low resistance and a fault state will cause Opto 1 to go into its high resistance
state.
Opto 1 will only output faults detected by the input board onto which it is installed. With a
dual power supply Hydrastep unit, this means it is necessary to used two opto-isolated output
boards (one on each input board) to create a system fault output.
TR2
(Switch SW6 set for Fault Signal operation)
Opto-output 1
TR4
Opto-output 2
+ VE - VE
Even Electrodes
(LH Input Board)
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
1
4
3
2
PL 2
1
4
3
2
PL 2
To alarm annunciator or
tripping device
Note: Systems with a local display have an opto-isolated system fault available from the
display board.
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-9
3C.3.2 ALARM AND TRIPPING FACILITIES
The output boards provide high and low water level alarm and trip facilities for the 2468
Hydrastep system. Four to eight opto-isolated outputs can be made available for each input
board fitted.
3c.3.2.1 Philosophy
A requirement in regulations concerning steam raising plant is the provision of an automatic
low water level shut-down or trip device. In the 2468 Hydrastep the opto-isolated output
board provides the required output signals for such devices.
In practical applications of shut-down systems two factors must be considered, the
consequences of spurious trips and the non-availability of a trip when required, due to
protection system faults.
The following opto-isolated output (for brevity this output title will be shortened to opto-
output) circuits are specific to the 2468 Hydrastep Level Indicator versions.
3c.3.2.2 Opto-Output Interconnections for Alarm/Tripping Systems
It is necessary to open the Hydrastep 2468 Electronic Enclosure to carry out any wiring,
therefore care must be taken when working inside the unit.
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
Note: Before any opto-output interconnections are made it is necessary to fulfil any safety
regulations governing the plant shutdown procedures.
Since one input board receives inputs from the odd numbered electrodes and the other input
board receives inputs from the even numbered electrodes, interconnections between odd
and even opto-isolated output boards will be required. The opto-outputs are normally open
circuit and are switched into a conducting mode (short circuit) when their dedicated electrode
detects its allotted water/steam state to signal an alarm.
The following are examples of opto-output configurations used.
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-10 24685034
3c.3.2.3 ‘One out of Two’ Opto-output Alarm System
Either of the opto-outputs involved can signal an alarm when their assigned electrode detects
a water/steam interface change. The alarm condition is selected by switch SW5 to provide
an opto-output in conducting mode in water W or in a conducting mode in steam S.
Case A - Opto-output circuit normally open circuit, short circuit either one to trip
TR2
(Switch SW5 is set to S for low level alarms and set to W for high level alarms)
Opto-output 1
TR2
Opto-output 1
+ VE - VE
Even Electrodes
(LH Input Board)
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
1
4
3
2
PL 2
1
4
3
2
PL 2
To alarm annunciator or
tripping device
Case B - Opto-output circuit normally short circuit, open circuit either one to trip
TR2
(Switch SW5 is set to W for low level alarms and set to S for high level alarms)
Opto-output 1
TR2
Opto-output 1
+ VE - VE
Even Electrodes
(LH Input Board)
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
1
4
3
2
PL 2
1
4
3
2
PL 2
To alarm annunciator or
tripping device
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-11
3c.3.2.4 ‘Two out of Two’ Opto-output Alarm System
This system requires both opto-outputs to operate to cause an alarm when their assigned
electrodes register an alarm condition.
Case A - Opto-output circuit normally open circuit, short circuit both to trip
TR2
(Switch SW5 is set to S for low level alarms and set to W for high level alarms)
Opto-output 1
TR2
Opto-output 1
+ VE - VE
Even Electrodes
(LH Input Board)
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
1
4
3
2
PL 2
1
4
3
2
PL 2
To alarm annunciator or
tripping device
Case B - Opto-output circuit normally short circuit, open circuit both to trip
TR2
(Switch SW5 is set to W for low level alarms and set to S for high level alarms)
Opto-output 1
TR2
Opto-output 1
+ VE - VE
Even Electrodes
(LH Input Board)
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
1
4
3
2
PL 2
1
4
3
2
PL 2
To alarm annunciator or
tripping device
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-12 24685034
3c.3.2.5 ‘Two out of Four’ Opto-output Alarm System
In the following diagrams (5A & 5B) indicate the electrode channel selected for
each opto-output. A fully functioning system (NO FAULTS) will perform a low level trip at
electrode level 3. For a high level trip, using electrode channels 11, 12, 9 and 10
respectively and switch SW5 set for W, a healthy system would trip at level 10.
Case A - Opto-output circuit normally open circuit, short circuit one pair to trip
1
4
3
2
5
8
7
6
TR2
PL 2
(Switch SW5 is set to S for low level alarms and set to W for high level alarms)
Opto-output 1
TR4
Opto-output 2
+ VE
- VE
To alarm
annunciator
or tripping
device
1
4
3
2
5
8
7
6
TR2
Opto-output 1
TR4
Opto-output 2
PL 2
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board) Even Electrodes
(LH Input Board)
4
3
12
Case B - Opto-output circuit normally short circuit, open circuit one in each pair to trip
1
4
3
2
5
8
7
6
TR2
PL 2
(Switch SW5 is set to W for low level alarms and set to S for high level alarms)
Opto-output 1
TR4
Opto-output 2
+ VE
- VE
To alarm
annunciator
or tripping
device
1
4
3
2
5
8
7
6
TR2
Opto-output 1
TR4
Opto-output 2
PL 2
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board) Even Electrodes
(LH Input Board)
4
3
12
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-13
3c.3.2.6 ‘Two out of Three’ Opto-output Alarm System
In the following diagrams (6A & 6B) indicate the electrode channel selected for each opto-
output. A fully functioning system (NO FAULTS) will cause a low level trip at electrode level 2.
Using high-level electrode channels and SW5 set to S, the circuit can perform a high level trip.
Note: Inputs from electrodes 1 & 2 are applied to two separate opto-outputs on their
respective boards.
Case A - Opto-output circuit normally open circuit, short circuit two to trip
1
4
3
2
5
8
7
6
TR2
PL 2
(Switch SW5 is set to S for low level alarms and set to W for high level alarms)
Opto-output 1
TR4
Opto-output 2
+ VE
- VE
To alarm
annunciator
or tripping
device
1
4
3
2
5
8
7
6
TR2
Opto-output 1
TR4
Opto-output 2
PL 2
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
Even Electrodes
(LH Input Board)
2
3
12
1
4
3
2
TR6
Opto-output 3
1
PL 3
Case B - Opto-output circuit normally short circuit, open circuit to trip
1
4
3
2
5
8
7
6
TR2
PL 2
(Switch SW5 is set to W for low level alarms and set to S for high level alarms)
Opto-output 1
TR4
Opto-output 2
+ VE
- VE
To alarm
annunciator
or tripping
device
1
4
3
2
5
8
7
6
TR2
Opto-output 1
TR4
Opto-output 2
PL 2
Note: External power must
be applied as shown.
See specification for
power requirements
Odd Electrodes
(RH Input Board)
Even Electrodes
(LH Input Board)
2
3
12
1
4
3
2
TR6
Opto-output 3
1
PL 3
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-14 24685034
3C.4 COMPONENT REPLACEMENT
The components used on the opto-isolated output board are fitted using ‘surface mount
technology’ and fault remedial action is by the replacement of the whole output board. The
only components fitted to the board that the general user can replace are the nylon spacers.
3C.4.1 REPLACEMENT OF NYLON SPACERS
The replacement of nylon spacers fitted to the output board requires access to the non-
component side of the PCB.
Note: Spacers will only be fitted on the output board if a second output board is to be fitted or
has been fitted.
The spacers are secured in their holes by nut and nylon washer. To carry out a spacer
replacement, the output board has to be removed from the input board. The procedure
adopted is:
WARNING Mains voltages are present in this instrument when power
is connected. De-energise before opening front cover.
1. Isolate the 2468 electronic enclosure from the power supply.
2. Gain access to the PCBs and undo sufficient
connections for the removal of the output board
containing the defective spacer.
3. Remove the output board(s) by applying pressure to
the upper spring-loaded spigots and easing the output
board oft its spacers and out of its Berg plug/socket
connection.
4. Undo the nut and washer securing the faulty spacer
and extract it from its hole, see inset diagram.
5. Fit the new spacer in position, align correctly on the
board and secure firmly using the M4 nut and nylon
washer.
6. Refit the PCB(s) into the enclosure, re-connect the
PCB(s) as required and close the enclosure cover.
Re-apply power if required.
3C.4.2 PARTS LIST - OPTO-ISOLATED OUTPUT BOARD 24680505
The following list items are available as spare parts:
Item Description Mobrey Part
Number Item Description Mobrey Part
Number
Electrical:
PCB assembly:
Socket 5K2 free (8-way)
Socket 5K3 free (8-way)
24680505A
351508100
351503100
Mechanical:
Spacer, nylon 15.9 LG
Washer, nylon
Nut, M4
412012080
411999910
410031020
Hydrastep 2468CB & 2468CD Manual Opto-isolated Output Board Option
24685034 3c-15
3C.5 SPECIFICATION
Outputs: 4 x Alarm/Trip Opto-isolated outputs
Opto-Isolated Output Rating:
Maximum Open-circuit Voltage: 30V dc.
Maximum Short-circuit Current: 1A
Short-circuit Voltage Drop: 1.1V maximum at 1A
Open-circuit Leakage Current: 1mA at 30V dc.
Opto-isolated Output Board Option Hydrastep 2468CB & 2468CD Manual
3c-16 24685034
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-1
4
Remote Display Options 24683B, C, & D
Contents
Page No.
4.1 REMOTE DISPLAY OPTIONS .................................................................. 4-3
4.2 CONFIGURATION .................................................................................... 4-4
4.2.1 RECONFIGURING THE 24683B AND 24683C REMOTE DISPLAY .... 4-4
4.2.2 RECONFIGURING THE 24683D REMOTE DISPLAY .......................... 4-5
4.3 MECHANICAL INSTALLATION ............................................................... 4-6
4.3.1 INSTALLING THE 24683B AND 24683C PANEL MOUNTED UNITS .. 4-6
4.3.2 INSTALLING THE 24683D WALL MOUNTED UNIT ............................. 4-6
4.4 ELECTRICAL INSTALLATION ................................................................. 4-7
4.4.1 STAR AND DAISY CHAIN CONNECTIONS ......................................... 4-8
4.4.2 EXAMPLE OF A ‘STAR CONNECTED’ SYSTEM ................................. 4-9
4.4.3 EXAMPLE OF A `DAISY CHAIN' SYSTEM ......................................... 4-10
4.1.4 CONNECTING CABLES TO THE REMOTE DISPLAY ....................... 4-11
4.1.5 CONNECTING THE DISPLAY CABLES TO HYDRASTEP 2468 ....... 4-12
4.5 SYSTEM OPERATION............................................................................ 4-13
4.6 FAULT ANALYSIS AND CORRECTIVE ACTION .................................. 4-13
4.7 COMPONENT REPLACEMENT ............................................................. 4-16
4.8 SPECIFICATION ..................................................................................... 4-17
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-2 24685034
Illustrations
Figure 4.1 - Location of link headers for selecting the display mode .................................... 4-4
Figure 4.2 - Interconnection cable for a single remote display ............................................. 4-7
Figure 4.3 - Star and daisy chain connections of remote displays ....................................... 4-8
Figure 4.4 - Star connection example for two remote displays ............................................. 4-9
Figure 4.5 - Daisy chain connection example for two remote displays ............................... 4-10
Figure 4.6 - Cable connection details for the remote display .............................................. 4-11
Tables
Table 4.1 - Fault Analysis and Correction Chart ................................................................. 4-13
Table 4.2 - Remote Display Replacement Parts ................................................................. 4-16
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-3
4.1 REMOTE DISPLAY OPTIONS
The 24683B, C, and D Remote Display Units give a repeat display of the water level state
and fault alarm state of the Hydrastep 2468 Electronic Gauging System.
Each type of remote display operates in the same way. The only difference between them is
in their mechanical construction. The 24683B is a small LED display for panel mounting; the
24683C is a large LED display for panel mounting; and the 24683D is a large LED display for
wall mounting, contained in a splash proof box to IP65 (NEMA 4X) standard.
On each type of remote display there are two columns of LEDs, a red column to indicate
steam and a green column to indicate water. This provides a clear indication of the water
level in the monitored system. The number of LEDs that may be illuminated depends on the
number of electrodes being used. To mask the unused LEDs, a blanking panel is provided:
this should be fitted on the inside of the front panel. An electrode fault, or a wiring or circuit
fault, is indicated by a yellow LED.
The 2468 will drive a maximum of six remote displays, using star or daisy chain connections.
One remote display can be powered from the 2468. All other remote displays must be
locally powered.
On each type of remote display, connection to the 2468 is made through a 20-way screw
clamp terminal block. Access to the terminal block on the 24683B and 24683C is via a cut-
out in the rear panel. Access to the terminal block on the 24683D is made via cable glands
on one end of the enclosure.
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-4 24685034
4.2 CONFIGURATION
All remote displays can be configured for operation with 8 to 16 electrodes (two LEDs per
electrode) or 18 to 32 electrodes (one LED per electrode). Remote displays are supplied
ready for operation with 8 to 16 electrodes. If a remote display is required to operate with 18
to 32 electrodes then it must be reconfigured. The procedure for each type of remote display
is described below.
4.2.1 RECONFIGURING THE 24683B AND 24683C REMOTE DISPLAY
The procedure for reconfiguring the 24683B and 24683C for operation with 18 to 32
electrodes is:
1. Undo the four screws securing the rear panel and remove the panel.
2. Withdraw the decoding PCB from the rear of the display unit. (Some force may be
necessary, initially, to disengage the decoding PCB from the LED PCB.)
3. Carefully remove the link headers from sockets LK2 and LK4 on the decoding PCB, by
easing them out with a suitable flat-bladed screwdriver. (See Figure 4.1)
4. Fit the link headers, removed in step 3, into sockets LK1 and LK3.
5. Refit the decoding PCB and the rear panel.
LK1
LK2
LK3
LK4
Note:
This figure shows the layout of the decoding pcb fitted to the 24683C and 24683D Remote
Displays. The layout of the decoding pcb in the 24683B Remote Display is slightly different, but the
arrangement of links LK1-LK4 is the same.
18-32
8-16
18-32
8-16
Figure 4.1 - Location of link headers for selecting the display mode
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-5
4.2.2 RECONFIGURING THE 24683D REMOTE DISPLAY
The procedure for reconfiguring the 24683D for operation with 18 to 32 electrodes is:
1. Undo the four screws securing the transparent cover and remove the cover.
2. Undo the four screws securing the front panel and lay the panel carefully away from the
top of the box, still connected by the ribbon cable.
3. Carefully remove the link headers from sockets LK2 and LK4 on the decoding PCB, by
easing them out with a suitable flat-bladed screwdriver. (See Figure 4.1)
4. Fit the link headers, removed in step 3, into sockets LK1 and LK3.
5. Refit the front panel and the transparent cover.
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-6 24685034
4.3 MECHANICAL INSTALLATION
Of the three types of remote display units, types 24683B and 24683C are intended for panel
mounting and type 24683D is intended for wall mounting. The installation procedures for
panel and wall mounting are described below.
4.3.1 INSTALLING THE 24683B AND 24683C PANEL MOUNTED UNITS
The panel related dimensions for the 24683B and 24683C are:
Panel thickness: 24683B = 2mm to 9mm
24683C = 2mm to 20mm
Aperture: 24683B = 139mm high × 67mm wide
24683C = 186mm high × 92mm wide
The installation procedure is:
1. Ensure that the panel on which the remote display is to be fitted provides easy access
to the electrical connections and is sited in a good viewing position.
2. Cut an aperture in the panel to the dimensions given above and remove any burrs.
3. Remove the clamps (if fitted) from the remote display unit and fit the unit into the
aperture from the front of the panel.
4. Refit the clamps to the display unit and secure the unit to the panel.
The two clamps on the 24683B and 24683C each clip onto two metal studs on the case of
the unit. Adjust the clamps from the rear of the unit with a suitable flat bladed screwdriver.
Tighten the clamps until they press firmly against the panel to hold the unit in place.
4.3.2 INSTALLING THE 24683D WALL MOUNTED UNIT
The 24683D Remote Display Unit is contained in an IP65 enclosure that can be fixed to the wall
by four mounting brackets. Cables are routed to the internal PCB through glands in the base.
The installation procedure is:
1. Place the unit against the surface to which it is to be fixed and mark the positions of the
fixing points. These should be positioned on centres 190mm apart horizontally and
305mm apart vertically. Install suitable fixings and secure the unit to the wall.
2. Remove the four screws securing the clear cover of the unit and place the cover
carefully to one side.
3. Remove the four screws securing the front panel of the unit and lay the panel, still
attached by its ribbon cable, on top of the case.
4. Loosen the cable gland nuts, pass the cables through the glands, prepare the cable
terminations, and fit the cable to the terminal block. (See Section 4.4.4 for details.)
5. Ensure that the cables are not strained within the unit, tighten the cable glands, and refit
the front panel and clear cover.
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-7
4.4 ELECTRICAL INSTALLATION
Up to six remote displays may be driven by the Hydrastep 2468 unit. One remote display can
be powered from the main unit, but all the others must have a local supply. A remote display
has a dual serial data input and a dual power input. When the remote display is powered from
the main unit an eight-core cable is required to connect the two units. When a remote display
is locally powered, however, a six-core cable will suffice. See the example in Figure 4.4:
remote display unit 1 is powered from the main unit and uses an eight-core cable; remote
display unit 2 is locally powered and uses a six-core cable. All cables must be screened to
comply with the EMC directive.
For remote displays powered from the main unit the loop resistance of the power conductors
must be less than 27 ohms for an a.c. powered unit or 7 ohms for a d.c. unit. To provide for
cable runs of up to 1000 metres, without the use of heavy cables, the main unit and the remote
display unit each have internally linked multiple terminals for the power and ground connections.
This allows the power and ground lines to be doubled to reduce the loop resistance.
Figure 4.2 - Interconnection cable for a single remote display
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-8 24685034
4.4.1 STAR AND DAISY CHAIN CONNECTIONS
Multiple remote display units can be connected to the main 2468 unit in two ways: ‘star’ or
‘daisy chain’. (See Figure 4.3) You can use either or both of these, in whichever way best
suits the relative locations of the 2468 unit and the remote displays. The maximum cable
length permitted between the 2468 and any remote unit is 1000 metres.
2468
RDU 1
RDU 2
RDU 3
RDU 4
RDU 5
RDU 6
Star
2468
RDU 1 RDU 2 RDU 3
RDU 4
RDU 5
RDU 6
Daisy
Chain
Figure 4.3 - Star and daisy chain connections of remote displays
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-9
4.4.2 EXAMPLE OF A ‘STAR CONNECTED’ SYSTEM
Figure 4.4 shows two remote displays connected in a ‘star’. Where more than one remote
display is in use, local supplies with isolated outputs must be used to power the extra unit(s).
Up to six remote displays can be supported (less their power requirements): with the full
complement of units in use, three signal carrying conductors must be connected to each
terminal.
Figure 4.4 - Star connection example for two remote displays
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-10 24685034
4.4.3 EXAMPLE OF A `DAISY CHAIN' SYSTEM
Figure 4.5 shows two remote displays connected in a `daisy chain'. Where more than one remote
display is in use, local supplies with isolated outputs must be used to power the extra unit(s).
To prevent signal reflections from corrupting the data, it may be necessary to fit termination
resistors to the last unit in the chain. The resistor values should match the characteristic
impedance of the cable (120, typical). A termination resistor is connected between pins 3 and
4, and 17 and 18, on terminal block TB1. A suitable resistor to use is a ¼W metal film type.
Figure 4.5 - Daisy chain connection example for two remote displays
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-11
4.4.4 CONNECTING CABLES TO THE REMOTE DISPLAY
The following procedure can be used for each remote display that is to be connected:
1. Gain access to the remote display terminal block. On the 24683B and 24683C remote
displays the terminal block is located at the rear of the unit. The terminal block of the
24683D remote display is located within the unit and must be accessed as described in
Section 4.3.2.
2. Prepare the cable ends and fit identity sleeves to the leads.
3. Fit the leads into the respective terminals (see Figure 4.6 for details) and tighten the
terminal screws. The interconnections for multiple remote displays are shown in the
examples in Figure 4.4 and Figure 4.5.
4. Ensure a stress-free exit for the cable, from the panel, by providing any necessary cable
support.
Figure 4.6 - Cable connection details for the remote display
Terminal Service
1 & 3 Signal + VE from 2468
2 & 4 Signal - VE from 2468
5, 6 & 7 Power 0V from 2468 or local supply
8 & 9 Power + VE from 2468 or local supply
12 & 13 Power + VE from 2468 or local supply
14, 15 & 16 Power 0V from 2468 or local supply
17 & 19 Signal - VE from 2468
18 & 20 Signal + VE from 2468
10 & 11 Earth
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-12 24685034
4.4.5 CONNECTING THE DISPLAY CABLES TO HYDRASTEP 2468
WARNING: Mains voltages are present in the 2468 Hydrastep unit when power is
connected. De-energise before opening the front cover.
The connection procedure is:
1. Ensure a stress-free cable run between the remote display unit and Hydrastep 2468.
2. Gain access to the display board in the 2468. The cable from the remote display
requires connecting to connectors PL3 and PL7 on PCB 24680515.
3. Enter the cable through the gland port in the 2468 enclosure (if this is applicable) and
ensure a stress-free run inside the enclosure.
4. Prepare the cable ends, fit identity sleeves on the leads and connect them to their
respective terminals. See the example in Figure 4.5.
5. Ensure that the cable screen is grounded at the gland plate.
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-13
4.5 SYSTEM OPERATION
When the system is brought on line check for complete agreement between the remote
display and the Hydrastep level indicator display.
4.6 FAULT ANALYSIS AND CORRECTIVE ACTION
Indication Fault Analysis and Corrective Action
No display of odd LEDs
(including bottom half of
fault LED.
Loss of power to
remote display unit. Check that the wiring to connector PL1 in the remote
display unit is correct.
With a suitable meter, check that the supply voltage is
present at the remote display unit connector. Ensure that
the voltage is in the range 14V through 45Vdc.
If the unit is locally powered and no voltage is present
check the voltage at the local power source.
If the unit is powered from the 2468 electronics unit check
the voltage between pins 5 and 8 of PL3 on the display
board (24680502) of that unit. A voltage of less than
14Vdc indicates the possibility of a short circuit in the
power lines or a fault on the display board. Disconnect
connector SK3 from the display PCB in the 2468
electronics unit and re-check the voltage between pins 5
and 8 of PL3. If the voltage is less than 18Vdc then the
display board in the 2468 electronics unit may be faulty.
Replace this board with a serviceable item and check for
the correct voltage between pins 5 and 8 of PL3.
No display of even
LEDs (including top half
of fault LED).
Loss of power to
remote display unit. Check that the wiring to connector PL2 in the remote
display unit is correct.
With a suitable meter, check that the supply voltage is
present at the remote display unit connector. Ensure that
the voltage is in the range 14V through 45Vdc.
If the unit is locally powered and no voltage is present
check the voltage at the local power source.
If the unit is powered from the 2468 electronics unit check
the voltage between pins 5 and 8 of PL7 on the display
board (24680502) of that unit. A voltage of less than
14Vdc indicates the possibility of a short circuit in the
power lines or a fault on the display board. Disconnect
connector SK3 from the display PCB in the 2468
electronics unit and re-check the voltage between pins 5
and 8 of PL7. If the voltage is less than 18Vdc then the
display board in the 2468 electronics unit may be faulty.
Replace this board with a serviceable item and check for
the correct voltage between pins 5 and 8 of PL7.
Table 4.1 - Fault Analysis and Correction Chart
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-14 24685034
Indication Fault Analysis and Corrective Action
Bottom half of fault
LED illuminated and
odd LEDs flashing at
1Hz, or odd LEDs off.
Power present, but
loss of serial data. Check that the wiring to connector PL1 in the remote
display unit is correct.
If wiring is correct, proceed as follows:
1. If a termination resistor is fitted, disconnect this from
the end of the daisy chain.
2. With an ac voltmeter, check the ac voltage between
pins 1and 5, and pins 2 and 5, on PL1.
3. An ac voltage is less than 1V indicates a fault on the
signal transmission lines. Check back to the previous
remote display in the daisy chain or to the 2468
electronics unit, as appropriate. If the correct ac
voltages are present at this location then a line break
is indicated.
4. If the ac voltages are still low then either the lines are
short-circuited or there is a board fault. Disconnect the
remote displays upstream and re-check the ac
voltages. If there is a voltage of less than 1Vac at the
2468 electronics unit (with PL3 removed) then the
display board is faulty. Remove this board and fit a
serviceable item.
Bottom half of fault
LED illuminated and
even LEDs flashing at
1Hz, or even LEDs off.
Power present, but
loss of serial data. Check that the wiring to connector PL2 in the remote
display unit is correct.
If wiring is correct, proceed as follows:
1. If a termination resistor is fitted, disconnect this from
the end of the daisy chain.
2. With an ac voltmeter, check the ac voltage between
pins 1and 5, and pins 2 and 5, on PL2.
3. An ac voltage is less than 1V indicates a fault on the
signal transmission lines. Check back to the previous
remote display in the daisy chain or to the 2468
electronics unit, as appropriate. If the correct ac
voltages are present at this location then a line break
is indicated.
4. If the ac voltages are still low then either the lines are
short-circuited or there is a board fault. Disconnect the
remote displays upstream and re-check the ac
voltages. If there is a voltage of less than 1Vac at the
2468 electronics unit (with PL7 removed) then the
display board is faulty. Remove this board and fit a
serviceable item.
Table 4.1 (cont.) - Fault Analysis and Correction Chart
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-15
Indication Fault Analysis and Corrective Action
Flickering Display Corruption of signal
data Most probably caused by bad shielding (screening) of the remote
display cabling or by bad shield connections to ground.
Check shielding and shield connections. Ensure that only one
end of the cable shield is connected to ground.
If several remote displays are ‘daisy chained’ together then a
termination resistor may be required on the end display. (See
Section 4.4.3 in this chapter.)
Chequered
pattern on red
and green LED
display
Wrong setting of
‘Number of
Electrodes’ switch
on 2468 display
board.
Refer to Section 2.3 in Chapter 2 and ensure that the switch is set
correctly. If the display still shows a chequered pattern then a
circuit fault exists on the 2468 display board. Remove this board
and fit a serviceable replacement.
On/off pattern on
red and green
LEDs.
Wrong setting of
‘Number of
Electrodes’ switch
on 2468 display
board, or wrong
setting of links LK1,
LK2, LK3 and LK4
on the 24683BB
decoding pcb.
As above.
If a fault is not found, check the link setting on the 24683BB and
reset the links if necessary.
Indication not
displayed for
lower electrodes. As above. As above.
Each electrode
represented by
only one LED
when 16 or less
electrodes are
used.
As above. As above.
LEDs display an
irregular
red/green
pattern.
As above. As above.
Table 4.1 (cont.) - Fault Analysis and Correction Chart
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-16 24685034
4.7 COMPONENT REPLACEMENT
Hydrastep remote display units contain no user-replaceable electronic components. Board
failure requires the faulty PCB to be removed and returned for service and a serviceable
PCB to be fitted in its place. A list of replacement parts is given in Table 4.2.
The procedure for replacing a PCB in a remote display is:
1. Ensure that the Hydrastep 2468 unit is switched off.
2. Gain access to the interior of the remote display unit. The method depends on the type
of remote display being serviced:
For a 24683B: Remove the cables from terminal block TB1 at the rear of the unit.
Remove the clamps. Withdraw the unit from the front of the mounting panel and lay on
a clean surface. Pull off the bezel from the unit front panel, unscrew and remove the
side panel, and lift off the front and rear panels, and use a suitable flat bladed
screwdriver to prise apart the PCB interconnecting edge connectors. Both PCBs can
now be removed from their securing slots in the unit case.
For a 24683C: Remove the cables from terminal block TB1 at the rear of the unit.
Remove the clamps. Withdraw the unit from the front of the mounting panel and lay on
a clean surface. Remove the front and rear panels. Both PCBs can now be removed
from the unit case.
For a 24683D: Remove the unit clear cover and the front panel. The LED display and
the decode PCB can now be accessed and it can easily be seen which screws and
connections it is necessary to remove in order to remove the faulty board(s).
3. Fit the serviceable PCB(s), following the reverse order to that given in step 2.
Item Mobrey
Part Number
For 24683B:
LED PCB assembly
Decode PCB assembly
Header (for 8-16, 18-32 electrode operation)
Holding bar (two off, with two knurled knobs)
24680514A
24680513B
399100390
460202260
For 24683C:
LED PCB assembly
Decode PCB assembly
Header (for 8-16, 18-32 electrode operation)
24680519A
24680520A
460202260
For 24683D
LED PCB assembly
Decode PCB assembly
Header (for 8-16, 18-32 electrode operation)
24680521A
24680522A
460202260
Table 4.2 - Remote Display Replacement Parts
Hydrastep 2468CB & 2468CD Manual Remote Display Options 24683B, C & D
24685034 4-17
4.8 SPECIFICATION
REMOTE DISPLAY UNITS
INDICATION Red/green 6mm×3mm LEDs
CASE STYLE 24683B and 24683C: Panel mounting;
24683D: Rugged enclosure, to IP65/NEMA 4X
DIMENSIONS 24683B: 144mm×72mm×200mm deep (5.67”×2.83” ×7.87”)
24683C: 192mm×96mm×209mm deep (7.56”×3.7” ×8.23”)
24683D: 302mm×186mm×175mm deep (11.89”×7.32” ×6.89”)
PANEL CUT-OUT 24683B: 139mm×67mm
24683C: 186mm×92mm (7.32”×3.62”)
POWER SUPPLY Derived from 2468 electronics unit or 20V - 54Vdc, 240mA
Absolute maximum limits at remote display terminals: 16V to 60Vdc
TERMINALS Screw-clamp
CABLES
Note: The following cables fulfil the minimum requirements. Heavier cables may be used.
Maximum gauge accepted by connectors is 16AWG (1. 5mm2).
Powered from 2468 electronics
(up to 1000m from 2468 unit)
BASEEFA conformity*
1.5mm2, 7×0.53mm individually shielded, 5-pair. Overall
shield. Galvanised steel wire armour. One cable
required. (Mobrey Part No.480121230)
Unit locally powered
(up to 1000m from main unit) 22 AWG (0.324mm2, 7×0.25mm) individually shielded, 2-pair
twisted (Belden type No. 8723). Two cables required.
22 AWG (0.324mm2, 7×0.25mm) individually shielded, 3-pair
twisted (Belden type No. 8777). One cable required.
Powered from 2468 electronics
(up to 250m from 2468 unit)
22 AWG (0.324mm2, 7×0.25mm) individually shielded, 2-pair
twisted (Belden type No. 8723). Two cables required.
22 AWG (0.324mm2, 7×0.25mm) individually shielded, 4-pair
twisted (Alpha Wire type No. 6054C). One cable required.
Powered from 2468 electronics
(up to 500m from 2468 unit)
22 AWG (0.324mm2, 7×0.25mm) individually shielded, 3-pair
twisted (Belden type No. 8777). Two cables required.
22 AWG (0.324mm2, 7×0.25mm) individually shielded, 6-pair
twisted (Belden type No. 8778). One cable required.
Powered from 2468 electronics
(up to 1000m from 2468 unit)
18 AWG (0.826mm2, 16×0.25mm) individually shielded, 3-pair
twisted (Belden type No. 9773). Two cables required.
22 AWG (0.826mm2, 16×0.25mm) individually shielded, 6-pair
twisted (Belden type No. 9774). One cable required.
* The main Hydrastep 2468 unit is approved for operation in a hazardous environment to EExnA T4. Compliance
with this approval requires that armoured cable is used to connect a remote display to the main unit. A remote
display must not be used in a hazardous environment.
Remote Display Options 24683B, C & D Hydrastep 2468CB & 2468CD Manual
4-18 24685034
Hydrastep Pressure Parts
Operating Manual
Part No: 24675030
Status: B
Issue: A
Authors: J. Smith / M. Le-Fevre / RCD
Date: March 2006
Pt.2-2 24675030
24675030 Pt.2-3
About this manual
This manual describes various procedures involved in the installation of the Hydrastep water columns, their
attachments and the electrodes used in determining the level of water in the column.
Part 2 - Pressure Parts
Chapter 1 is a general introduction to the Hydrastep system of water level determination.
Chapter 2 describes the water column and its components. The preparation, installation of the water column on to
the boiler, acid and steam purging of the boiler system and the fitting of the electrode sensors.
Chapter 3 details the fault repair procedures carried out on the system pressure parts and their commissioning.
Chapter 4 provides a general description of the pressure parts used in the Hydrastep systems.
Chapter 5 details the Pressure Parts specifications.
CAUTION: The procedures described in this manual do not overrule any mandatory
regulations and procedures applied on site regarding the installation, testing and safety
precautions affecting the specific Hydrastep System.
The objective of this manual is to describe various procedures involved in the installation of the
water columns, their attachments and the electrodes used in determining the level of water in the
column as required by the following Hydrastep Systems.
Commissioning the water column and limited component repair procedures on the system
pipework are also covered.
Pt.2-4 24675030
24675030 Pt.2-5
R E M I N D E R
ELECTRODE INSTALLATION
THREADED ELECTRODE(S), PART Nos. 459600602 & 459600802
MAKE SURE THAT THE COMPRESSION GASKET IS REGISTERED IN THE
PROBE RECESS PRIOR TO TIGHTENING THE ELECTRODE. THIS CENTRES
THE GASKET TO THE PROBE.
CORRECT INCORRECT
ELECTRODE
COLUMN BODY
GASKET
SEAT SURFACE
Pt.2-6 24675030
24675030 Pt.2-7
N O T I C E
THE HYDRASTEP VESSEL AND PROBE SYSTEM
PROVIDES A SELF-FLUSHING FEATURE THAT PREVENTS
THE ACCUMULATION OF DEBRIS IN THE VESSEL.
THIS ELIMINATES THE NEED FOR PERIODIC BLOWING
DOWN OF THE VESSEL.
DO NOT BLOW DOWN THE HYDRASTEP VESSEL IF A
BLOCKAGE IS SUSPECTED.
REFER TO THE APPROPRIATE MANUAL SECTION FOR
PROPER DIAGNOSTIC PROCEDURES IF BLOCKAGE
PROBLEMS ARE SUSPECTED.
Pt.2-8 24675030
24675030 Pt.2-9
Part 2 - Hydrastep Pressure Parts
Chapter 1 General Introduction
Chapter 2 Installation Procedures
Chapter 3 Fault Repair and Commissioning
Chapter 4 Unit Description
Chapter 5 Unit Specifications - Hydrastep
Pt.2-10 24675030
Hydrastep Pressure Parts General Introduction
24675030 1-1
1
General Introduction
1.1 PRINCIPLE OF OPERATION ................................................................... 1-3
1.2 WATER LEVEL INDICATION ................................................................... 1-3
Illustrations
Figure 1.1 - Schematic of high pressure resistance measuring cell and electrodes ............. 1-3
Figure 1.2 - Low pressure water column (120bar, 1740psi) .................................................. 1-4
Figure 1.3 - High pressure water column (210 bar, 3045psi and 300 bar, 4350psi) ............. 1-5
General Introduction Hydrastep Pressure Parts
1-2 24675030
Hydrastep Pressure Parts General Introduction
24675030 1-3
1.1 PRINCIPLE OF OPERATION
The Hydrastep systems have been designed as electronic alternatives to conventional visual
water gauges on boilers, giving more reliable and safer water level indication.
The system is based on the significant differences in resistivities of water and steam over
the range 100C (212F) to 370C (698F). (Series 3 super-critical components are used up
to 560C, 1040F)
A vertical row of electrodes is installed in the water column which forms a side arm attached
to a boiler arid aligned, typically, such that an equal number of electrodes appear above and
below the normal water level, see Figure 1.1. The resistance measurement is made
between the insulated tip of the electrode and the wall of the column. The cell constant,
defining the actual resistance measured, is determined by the length and the diameter of the
electrode tip and the water column bore. In practice, the cell constant is chosen so that the
resistance in water is less than 100k ohms, with a consequent resistance in steam of greater
than 10M ohms.
Since the resistivities of water and steam are substantially different, the system is simple
and requires minimum setting up adjustments. It is not critical in terms of power supply
variations, ambient temperature changes, etc., resulting in a highly reliable system.
Figure 1.1 shows the resistance-measuring cell complete with installed electrode. Figure 1.2
and Figure 1.3 show examples of the Low Pressure (120bar, 1740p.s.i.) and the Series 3
and Super 3 High Pressure (210bar, 3045p.s.i. & 300bar, 4350p.s.i.) Water Columns
respectively.
1.2 WATER LEVEL INDICATION
Each electrode is connected to its own electronic measurement channel where the
resistance value measured decides which of two Light Emitting Diode (LED) drive circuits is
energised. The LEDs are presented in two columns, one column of green LEDs (illuminated
for water) and one column of red LEDs (illuminated for steam) indicating the water level.
Figure 1.1 - Schematic of high pressure resistance measuring cell and electrodes
General Introduction Hydrastep Pressure Parts
1-4 24675030
Figure 1.2 - Low pressure water column (120bar, 1740psi)
Hydrastep Pressure Parts General Introduction
24675030 1-5
Figure 1.3 - High pressure water column (210 bar, 3045psi and 300 bar, 4350psi)
General Introduction Hydrastep Pressure Parts
1-6 24675030
Hydrastep Pressure Parts Installation Procedures
24675030 2-1
2
Installation Procedures
Contents
Page No.
2.1 SCOPE OF PROCEDURES ...................................................................... 2-3
2.2 STORAGE ................................................................................................. 2-3
2.2.1 AMBIENT CONDITIONS ......................................................................... 2-3
2.2.2 PHYSICAL PROTECTION ...................................................................... 2-3
2.2.3 INSPECTION ........................................................................................... 2-3
2.2.4 HANDLING PRECAUTIONS ................................................................... 2-3
2.3 INSTALLATION OF WATER COLUMN ................................................... 2-3
2.4 INSPECTION OF MECHANICAL INSTALLATION WORK ...................... 2-6
Illustrations
Figure 2.1 - Universal weld profile ......................................................................................... 2-5
Figure 2.2 - Typical water column installation ....................................................................... 2-7
Figure 2.3 - Typical water column suspension ...................................................................... 2-8
Installation Procedures Hydrastep Pressure Parts
2-2 24675030
Installation Procedures Hydrastep Pressure Parts
24675030 2-3
2.1 SCOPE OF PROCEDURES
The procedures apply to the Hydrastep Boiler Drum Water Level Equipment supplied by
Mobrey, who are responsible, under their supply contract, for delivery of all items of the
above equipment listed in the delivery schedules.
Mobrey are not responsible for handling, storage, installation and protection of equipment on-
site. However, the procedures define the requirements for these activities which must be
complied with to allow Mobrey to meet their contractual obligations for the efficient
performance of equipment supplied by them.
The items of equipment are listed in detail on the ‘Packing Note’ that is issued with the
equipment to the site.
2.2 STORAGE
2.2.1 AMBIENT CONDITIONS
The storage area must be dry, dust-free and under cover. Storage conditions should be
controlled within the temperature range of 10C to 40C (50F to 104F) with a maximum of
80% R.H.
2.2.2 PHYSICAL PROTECTION
The equipment shall be stored, where possible, in the original or robust packages to prevent
accidental mechanical damage. The equipment shall be stored on shelving or racks above
ground level as further protection from mechanical damage and to eliminate dampness.
2.2.3 INSPECTION
If the equipment is to be stored for a long period, suitable access is to be provided so that
regular inspection can take place. These inspections should check for signs of physical
deterioration, and should take place at least every three months.
2.2.4 HANDLING PRECAUTIONS
The water columns are heavy and lifting equipment suitable for hoisting up to 50kg should be
used, both for inspection and carriage. The electrodes should be handled with considerable
care, both for inspection and installation. The electronic units should be protected from
electrostatic damage, induced via signal input terminals.
2.3 INSTALLATION OF WATER COLUMN
The Water Column is delivered with all electrode ports fitted with plastic inserts. These
inserts should not be removed until the electrodes are due to be installed.
Installation Procedures Hydrastep Pressure Parts
2-4 24675030
The water column is delivered along with the correct number of electrodes of the relevant
pressure type (high or low) and complete with gaskets or ferrules and fixing nuts, where
applicable. The electrodes should only be fitted to the column after all erection and electrical
work is completed and the water column is ready to be commissioned.
Caution: It is essential that the electrodes are NOT fitted until the acid and steam purging
of the boiler drum has been completed. However, if it is essential that the
Hydrastep be used to gauge the water level during acid cleaning, a sacrificial set
of electrodes must be used for this task with a new set of electrodes provided for
installation before normal operation is started. Sacrificial electrodes should be
discarded.
The water column is provided with a lifting eye at its upper end to be used for support from
the local site superstructure.
Before fitting the water column, the following points must be checked:
a) Ensure that access to work on this part of the plant is clear and that the Column isolating
Valves have been fitted to the Steam and the Water connections on the Drum and are
ready to have the water column welded to them. All steam isolation valves should be
fitted with their spindles horizontal.
b) Check that items of hardware required for supporting the water column are available and
that the suspension points on the superstructure have been installed.
c) Water columns are normally supplied with a lifting/support eye, but where this is not the
case, alternative support must be provided.
d) The water column and associated pipework are secured to resist sympathetic vibrations
from surrounding plant.
e) Ensure that the relevant installation diagrams, support services including that of an
approved welder, and suitable welding plant are available.
Note: All joints in pipework must be welded, tested and inspected in accordance with
the approved welding procedure documents. Ideally, this should be to ASME B &
PVC Section IX Welding Qualifications, but Local Regulations may otherwise
apply. To minimise errors due to temperature difference between the water in the
boiler drum and the water in the Hydrastep column, the length of the pipework
between the drum and the Hydrastep column should not exceed 2 metres. Paths
should be as straight and direct as possible.
Installation Procedures Hydrastep Pressure Parts
24675030 2-5
Figure 2.1 - Universal weld profile
The Steam and Water connections on the water column must be set to position the water
column at the correct level before they are welded in place, Figure 2.2 gives an example of
the water column installation. Normally, the water level of the drum will be between
electrodes 6 and 7 for a twelve port water column. However, due to the physical or operating
conditions, this could be offset. The steam leg must slope downwards to the water column
with a minimum gradient of 1 in 50 to ensure condensate circulation. The water leg must
slope downwards to the drum to prevent water from being trapped at the bottom of the water
column.
Caution: Care must be exercised to ensure that the pipework is not allowed to take the
unsupported weight of a standard water column. The weight of the column and
its associated pipework are fully supported - there must not be any load on the
welded pipework attachment points.
Installation should commence with the support of the column, see Figure 2.3. The water
column is attached to the supports which will carry the weight of the water column and allow
it to be accurately aligned with the drum steam and water connections before and during the
welding operation.
After the welding to the connecting pipework, valves and the fitting of the drain pipework is
complete, a further check on the level alignment must be carried out and adjustments made,
if necessary.
45°
1.5mm
For HP (210 bar) Material: SA106B
Size: 1" N.B, Sch. 160 pipe dim.
For HP (300 bar) Material: SA479 - 316
Size: 1" N.B, Sch. XXS PPE
For LP Material: SA106B
Size: 1" N.B, Sch. 80 pipe dim.
Installation Procedures Hydrastep Pressure Parts
2-6 24675030
The water connection to the water column must be fully insulated by lagging. The steam
connection must also be lagged, but a minimum length of 0.5 metre of the steam leg must be
left unlagged where the steam leg joins the water column (see Figure 2.2).
Lagging the water column will reduce the density error, provided that 0.5 metre minimum of
the steam leg is left unlagged.
If errors in the water level indication are observed, it may be necessary to lag the water
column, either up to NWL or for it’s full length, depending on the ambient conditions
prevailing at the site. Suitable lagging, part number 450601450, is available from Mobrey.
When the installation of the water column has been completed, precautions must be taken to
protect it against damage during the installation of adjacent plant and pipework.
Note: Particular attention must be paid to the protection of the electrode sealing
surfaces in the column against foreign bodies or weathering. For this purpose the
following sealing plugs should be fitted as appropriate:
L.P. Sealing Plug Part No. 24569A
Series 3 Sealing Plug Part No. 450600880
Caution: If there is any possibility of the ambient temperature at drum level falling below
zero C for any period when the boiler is not operational, it is ESSENTIAL that the
water column is isolated, drained and vented to prevent ice-expansion damage to
the electrodes in the column. Ice-expansion damage can also affect adjacent
valves.
For instructions regarding the assembly of electrodes in the water column, see Chapter 3,
sub-section 3.1.4 (low pressure electrodes) and 3.1.5 (high pressure electrodes).
2.4 INSPECTION OF MECHANICAL INSTALLATION WORK
When the mechanical installation work has been completed, the site surveillance staff may
be required to inspect the work and the equipment, such as the installation of the electronics
unit and the installation of the water column, checking particularly the level relative to the
drum, before releasing it for electrical work and cabling.
Installation Procedures Hydrastep Pressure Parts
24675030 2-7
Figure 2.2 - Typical water column installation, showing optional column lagging.
Installation Procedures Hydrastep Pressure Parts
2-8 24675030
Figure 2.3 - Typical water column suspension
Hydrastep Pressure Parts Fault Repair and Commissioning
24675030 3-1
3
Fault Repair and Commissioning
Contents
Page No.
3.1 BACKGROUND 3-3
3.1.1 SAFETY PRECAUTIONS .......................................................................... 3-3
3.1.2 WATER COLUMN ISOLATION ................................................................. 3-4
3.1.3 ELECTRODE AND ELECTRODE SEAL LEAKS ...................................... 3-4
3.1.3.1 LOW PRESSURE ELECTRODES .......................................................... 3-4
3.1.3.2 HIGH PRESSURE ELECTRODES ......................................................... 3-5
3.1.3.3 TIGHTENING PROCEDURE FOR HIGH PRESSURE ELECTRODE
INSTALLATION ....................................................................................... 3-5
3.1.4 PROCEDURE FOR CHANGING THE LOW PRESSURE ELECTRODES
AND GASKETS ......................................................................................... 3-5
3.1.5 PROCEDURE FOR CHANGING HIGH PRESSURE ELECTRODES ....... 3-6
3.2 WATER COLUMN COMMISSIONING OR RECOMMISSIONING 3-6
3.2.1 VENT AND DRAIN VALVE REPAIRS ....................................................... 3-6
3.2.2 WATER COLUMN TRANSIENT RESPONSE ........................................... 3-7
3.2.3 WATER COLUMN OR PIPEWORK BLOCKAGE...................................... 3-7
3.2.4 WATER COLUMN LIFE ............................................................................ 3-7
Note:
THERE IS NO NEED TO BLOW WATER COLUMN DOWN WHEN COMMISSIONING.
THE SYSTEM CONTINUOUSLY FLUSHES THE WATER COLUMN.
Fault Repair and Commissioning Hydrastep Pressure Parts
3-2 24675030
Hydrastep Pressure Parts Fault Repair and Commissioning
24675030 3-3
3.1 BACKGROUND
With any steam/water detection gauge, a partial blockage or leak within the pressurised
system may result in incorrect water level indication. The Hydrastep water column design is
such that density errors in water level indication (due to the water temperature in the column
being lower than the water temperature in the boiler drum) are minimised for the
temperatures and pressures specified. This is achieved by stimulating condensate flow in
the upper part of the column by omitting lagging on the column steam pipe. The flow of
condensate maintains the temperature of the water column close to that of the boiler drum.
Caution: If a serious “blow” occurs, immediate attention is required. Ensure that the
column or manifold is VALVED OFF AS SOON AS POSSIBLE otherwise any
resulting electrode seat erosion may require the removal of the column or
manifold for re-machining of the ports. Site machining of the water column is
possible and satisfactory results can usually be obtained (for small leak damage).
3.1.1 SAFETY PRECAUTIONS
a) Ensure that tripping, where fitted, is disabled and that the operators are briefed to
expect erroneous indications or alarms.
b) Ensure that you know the valve positions and other procedures BEFORE working on the
water column.
c) Allow the water column to cool before changing electrodes and check for signs of steam
at the drain to ensure complete isolation.
d) Wear industrial gloves to change electrodes.
e) On Low-level Tripping Schemes, either electro-mechanical interlocks or recognised
procedures MUST be applied to ensure that draining the column does not cause a
spurious trip.
f) Refit the electrode covers before pressurising the column.
g) It is strongly recommended that a ‘HOT’ notice is attached to the water column in a
prominent position.
h) Ensure that all safe working practices for the media and processes concerned are
followed during the installation and maintenance of the equipment.
i) If the equipment is likely to come into contact with aggressive substances, it is the
responsibility of the user to take suitable precautions that prevent it from being
adversely affected, thus ensuring that the type of protection both mechanical and
electrical are not compromised.
j) The equipment, both mechanical and electrical, must not be used as a support for other
equipment or personnel.
k) Both mechanical and electrical content of the system must be protected from impact.
l) The Hydrastep installation is not protected by integral over pressure relief valves. Where
fitted directly to a boiler installation, ensure the Hydrastep water column and associated
pipework are protected from over pressurisation by the boiler safety valves.
Fault Repair and Commissioning Hydrastep Pressure Parts
3-4 24675030
3.1.2 WATER COLUMN ISOLATION
After obtaining authority to isolate the column:
a) Close off the steam and water isolating valves.
b) Where the column is connected to a closed drain, open the drain valve and, when the
pressure equalises, close the drain valve.
c) Check for no-pressure condition of water column. A failure to cool and a re-filling of the
water column would indicate a pressure condition. Alternatively, carefully unscrew the
first electrode and look out for the presence of steam.
Warning: Great care is required during the check on the first electrode.
Where a separate atmospheric drain is used, open the drain valve and leave it open.
d) Proceed with the work required.
3.1.3 ELECTRODE AND ELECTRODE SEAL LEAKS
The distinction between electrode/insert seal and electrode/insulator leaks is often difficult to
determine prior to removal of the electrode, unless the leak is small. Steam wisps which
appear to come from between the outside of the electrode body and the gasket indicate a
seal leak, steam appearing through the external ceramic insulator suggests that the
electrode itself is faulty. Even if the electrode is in water, the water temperature in an
operating system will cause the water to flash off to steam as atmospheric conditions are
reached.
Caution: Do not attempt to cure a leaking seal on a low pressure electrode by
overtightening the electrode clamping nut. The most probable fault for low
pressure electrodes lies in damage to the sealing washer. The correct degree
of compression on this washer is inherent in its design. Tightening beyond this
point will only cause damage to the electrode or to the water column.
3.1.3.1 Low Pressure Electrodes
The correct procedure on low pressure electrodes for repairing either a seal or an electrode
failure is to remove the knurled nut(s) and disconnect the electrode lead(s). Next, remove
the electrode complete with its sealing washer from the column. A thorough examination of
the electrode and washer is likely to give a more positive identification of the cause of the
leak. However, unless it can be definitely established that the electrode was not at fault, it is
advisable to fit a new electrode at this stage. To assist in identifying a seal leak, this may be
caused by:
a) Failure to remove the old washer on a previous occasion before inserting the
replacement washer and electrode.
b) Re-using an old and already compressed washer instead of a new one.
c) Failing to ensure that the land and the recess in the electrode port were clean and
undistorted at the last inspection.
Note: When installing low pressure electrodes, ensure that the threads in the electrode port
are free of loose particles. Lightly coat the electrode threads with anti-seize
compound (Part No. 830007220). Insert the electrode, ensuring that the new gasket
is centred in the electrode groove, and tighten the electrode with a torque wrench to
40 lbft (55Nm). After 15 minutes, re-tighten the electrode with the torque wrench set
to 40 lbft (55Nm). The maximum torque is 50 lbft (68Nm) so DO NOT OVERTIGHTEN.
Hydrastep Pressure Parts Fault Repair and Commissioning
24675030 3-5
Where scoring or erosion of the electrode port seat has occurred in the water column, the
seat can be re-cut to acceptable standards using a service tool as listed below.
Service Tool 246791AA – for use with electrodes 246781A* and 246781Z* only
Service Tool 246722AA – for use with electrode 246782A* only
3.1.3.2 High Pressure Electrodes
In the case of high pressure electrodes, sealing is performed by a taper form on the
electrode body. The act of tightening the electrode clamping nut compresses the taper form
into the port sealing taper, thereby effecting a pressure seal. For these electrodes, the
condition of the electrode port sealing surface is of great importance, and the tightening
procedure is given to prevent damage to the electrode or the water column electrode port.
Should a leak develop, the electrode must be removed and both the port and taper seating
surfaces examined for signs of surface deterioration.
3.1.3.3 Tightening Procedure For High Pressure Electrode Installation
a) Ensure the electrode is clean and the electrode port bore is clean and free of debris.
b) Lightly coat the column port thread with anti-seize compound (Part No.: 830007220).
c) Assemble the electrode to the column port and tighten the electrode nut until the
electrode will not rotate in its seat.
d) Finally, tighten the electrode nut a further 1/8 to ¼ turn to complete the procedure.
NOTE: The final 1/8 to ¼ turn corresponds to a torque level of between 28lbft (35Nm)
and 47lbft (60Nm). 1/8 turn is the recommended tightening condition. ¼ turn is the
maximum allowable, and the tightening torque used must be the minimum to achieve
this. Failure to comply with this limitation may cause damage to the port or to the
electrode, due to over tightening.
If necessary, where the sealing surfaces can be recovered by simple cleaning practices, the
old electrode can be refitted and tightened to within the maximum torque value given and the
system pressure tested. However, it is recommended that the best solution to minimise the
system ‘down time’ is to fit a new electrode.
Where scoring or erosion of the sealing seat has occurred in the water column port, this can be
re-cut to acceptable standards using the Service Tool 246791AA or 246722AA (see above).
3.1.4 PROCEDURE FOR CHANGING THE LOW PRESSURE ELECTRODES
AND GASKETS
Carry out the isolation procedure as detailed in sub-section 3.1.2. Ensure that the tripping is
disabled (see ‘Safety Precautions, sub-section 3.1.1). There is no need to switch off the
Hydrastep electronic equipment; then:
a) Remove the electrode cover guard, taking care to avoid knocking the electrodes.
Note: Remove only one electrode at a time (avoids risk of incorrect reconnection).
b) Disconnect the leads, extract the electrode and the gasket carefully without damage to
the seat face.
c) Inspect the column seat, making sure that it is free of loose particles and is not pitted or
corroded.
d) Carefully unpack the new electrode and check that there is no damage to the ceramic
insulators or to the sealing gasket.
e) Assemble the new electrode to the water column as detailed in sub-paragraph 3.1.3 for
low pressure electrodes, paragraph d.
Fault Repair and Commissioning Hydrastep Pressure Parts
3-6 24675030
f) Refit the electrical lead(s) and guard. Recommission as detailed later in this Chapter.
3.1.5 PROCEDURE FOR CHANGING HIGH PRESSURE ELECTRODES
Carry out the isolation procedure as detailed in sub-section 3.1.2. Ensure that the tripping is
disabled (see ‘Safety Precautions’, sub-section 3.1.1). There is no need to switch off the
Hydrastep electronic equipment; allow system about 20 minutes to cool down, then:
a) Remove the electrode cover guard, taking care to avoid knocking the electrodes.
Note: Remove only one electrode at a time (avoids risk of incorrect reconnection)
b) Disconnect the leads, extract the electrode carefully without damage to the seat face.
c) Inspect the column seat, remove any scaling or residue taking care not to damage the seat.
d) Carefully unpack the new electrode and check that there is no damage to the ceramic
insulators or to the seating ferrules.
e) Lightly coat the electrode threads with anti-seize compound (Part No.: 830007220) and
assemble the new electrode to the water column as detailed in sub-section 3.1.3 for
high pressure electrodes.
Note: At the first pressure/temperature test, check for leaks and tighten electrode nut as
necessary, but not exceeding ¼ turn from the ‘nipped electrode’ condition.
f) Refit the electrical lead(s) and guard. Recommission as stated in section 3.2.
3.2 WATER COLUMN COMMISSIONING OR RECOMMISSIONING
The method given allows the column to fill slowly with condensate from the steam leg
through a ‘cracked’ steam valve and for subsequent warming to continue at a controlled rate
as the water is forced back through the ‘cracked’ water valve.
Caution: DO NOT BLOW WATER COLUMN DOWN
a) Notify the unit operator of the intention to commission the column, in accordance with
recognised procedures.
b) Check that the electrode guard is in place.
c) Close the drain valves.
d) Crack open the steam valve. Check with the display or the unit operator that the column
fills with condensate slowly (10 to 15 minutes).
e) Crack open the water isolating valve. Check with the unit operator that the water level is
falling (1 to 2 minutes) to approximately normal water level and allow to stabilise and
heat up for 15 minutes.
f) Open the water valve fully.
g) Open the steam valve fully.
3.2.1 VENT AND DRAIN VALVE REPAIRS
These will usually involve replacement of the gland packing or regrinding of the seat, and
should follow the normal practice for the particular valve types concerned. If it is necessary
to replace an entire valve, ensure that the new valve is correctly orientated for its sealing
direction.
Hydrastep Pressure Parts Fault Repair and Commissioning
24675030 3-7
3.2.2 WATER COLUMN TRANSIENT RESPONSE
Starting with the water level at or below mid-gauge, note the lowest ‘steam’ indicating
channel at this stage and fully close the water isolating valve nearest the water column
quickly. Time the rise in water level due to the condensate flow until the topmost channel
changes to a ‘water’ indication. Now re-open the water isolating valve fully and quickly.
Time the fall in water level, from the ‘change to steam’ at the topmost level to the ‘change to
steam’ at the channel immediately above the lowest channel to indicate steam at the start of
the measurements.
The measured times should be similar to those obtained when the Hydrastep was first
commissioned, provided that the drum operating conditions are similar. The usual times are
in the region of 60 seconds for the rising levels and 5 to 15 seconds for the falling levels.
Any serious variation from these times for a ‘standard length column’ suggests either a partial
blockage or the water valve failing to seal properly.
Note: A ‘standard length column’ is 550mm (22 inches) sight range. Larger sight ranges will
proportionally extend the water level rise and fall times.
3.2.3 WATER COLUMN OR PIPEWORK BLOCKAGE
If a blockage, either partial or complete, is diagnosed from the response times, isolate the
column as described in ‘Water Column Isolation’, sub-section 3.1.2. With the drain valve
open, slowly open the steam isolating valve until the steam line is completely cleared. Close
the steam valve fully. Slowly open the water isolating valve until the water line is also
completely cleared. Close the water valve fully. Close the drain valve and re-check the
transient response. If the response times are still seriously in error, it is probable that the
steam or water valve is not seating or opening properly and needs re-seating.
Note: Ensure that all valves are left correctly set and locked.
3.2.4 WATER COLUMN LIFE
The water column life may be reduced if the water quality is not monitored and kept
chemically inert and pure. The end user is advised to pay particular attention to this water
quality requirement to safeguard the longevity of the Hydrastep pressure parts.
Fault Repair and Commissioning Hydrastep Pressure Parts
3-8 24675030
Hydrastep Pressure Parts Unit Description
24675030 4-1
4
Unit Description
Contents
Page No.
4.1 LOW PRESSURE ELECTRODES ............................................................ 4-3
4.2 HIGH PRESSURE ELECTRODES ........................................................... 4-4
4.3 WATER COLUMN (L.P.) ........................................................................... 4-5
4.4 WATER COLUMN (H.P.) .......................................................................... 4-6
4.5 WATER COLUMN (H.P. SUPERCRITICAL) ............................................ 4-7
Illustrations
Figure 4.1 - Low pressure electrode ...................................................................................... 4-3
Figure 4.2 - High pressure electrode...................................................................................... 4-4
Unit Description Hydrastep Pressure Parts
4-2 24675030
Hydrastep Pressure Parts Unit Description
24675030 4-3
4.1 LOW PRESSURE ELECTRODES
These electrodes can be used for pressures of 50bar (725psi) for 459600802 units, and up to
120bar (1740psi) for 459600602 units - see Chapter 5 for Specifications. They are used with
the low pressure version of the Hydrastep water column shown in Figure 1.2 (in Chapter 1,
Part 2 of the manual).
Fitting instructions are supplied on the electrode package. Electrode details for this version
are shown in Figure 4.1.
Figure 4.1 - Low pressure electrode
Unit Description Hydrastep Pressure Parts
4-4 24675030
4.2 HIGH PRESSURE ELECTRODES
High pressure electrodes can be used for pressures in the range 50bar (725psi) to 300bar
(4350psi) see Chapter 5 for Specifications. These electrodes are used with the high
pressure water column shown in Figure 1.3 (in Chapter 1, Part 2 of the manual). The fitting
instructions for high pressure electrodes are included within the electrode package.
High pressure electrodes are supplied complete with ferrules fitted. See Figure 4.2.
Figure 4.2 - High pressure electrode
Hydrastep Pressure Parts Unit Description
24675030 4-5
4.3 WATER COLUMN (L.P.)
The low pressure water column is manufactured from carbon steel, extruded rectangular
hollow bar. The electrode ports are drilled and fitted with ‘helicoil’ inserts to accept the
electrodes. This thread system gives greater strength than if the electrodes were mounted
directly into tapped ports. Corrosion of the threads is minimised since the ‘helicoil’ inserts are
made of stainless steel.
The top cap and the drain components of the water column are manufactured from forged
carbon steel bar, the drain components being available in ¾" and 1" sizes. A lug is machined
on the top cap to accept a vertical forked member for support of the water column when in
situ.
The steam and water connections are made from 1” N.B SCH 80 carbon steel pipe with weld
preps already machined to weld the water column to the steam system.
The electrode covers are fabricated from stainless steel with support blocks attached to the
column body. The covers are held in place by screw fasteners.
The complete assembly is of welded construction, with the welding to ASME
requirements. The materials and design are to ASME B31.1.
The completed water column undergoes pressure proof tests at 150% of duty pressure after
manufacture.
For further details on the water column dimensions, etc., refer to Figure 1.2 in Chapter 1, part
two of the manual.
Unit Description Hydrastep Pressure Parts
4-6 24675030
4.4 WATER COLUMN (H.P.)
The high pressure water column is manufactured from 2” NB SCH S carbon steel pipe.
The inserts used are made from high grade stainless steel and are welded into position on
the water column body.
The top cap and the drain components of the water column are manufactured from forged
carbon steel bar, the drain components being available in ¾” and 1” sizes. A lug is machined
on the top cap to accept a vertical forked member for support of the water column when in
situ.
The steam and water connections are made from 1” N.B SCH 160 carbon steel pipe with
weld preps already machined to weld the water column to the steam system.
The electrode covers are fabricated from stainless steel with support blocks attached to the
column body. The covers are held in place by screw fasteners.
The complete assembly is of welded construction, with the welding to ASME
requirements. The materials and design are to ASME B31.1.
The completed water column undergoes pressure proof tests at 150% of duty pressure after
manufacture.
For further details on the water column dimensions, etc., refer to Figure 1.3 in Chapter 1, part
two of the manual.
Hydrastep Pressure Parts Unit Description
24675030 4-7
4.5 WATER COLUMN (H.P. SUPERCRITICAL)
The high pressure water column is manufactured from 2” NB SCH S stainless steel pipe.
The inserts used are made from Stainless steel and are welded into position on the water
column body.
The top cap and the drain components of the water column are manufactured from forged
stainless steel, the drain components being available in ¾” and 1” sizes. A lug is machined on
the top cap to accept a vertical forked member for support of the water column when in situ.
The steam and water connections are made from 1” NB SCH S stainless steel pipe with
weld preps already machined to weld the water column to the steam system.
The electrode covers are fabricated from stainless steel with support blocks attached to the
column body. The covers are held in place by screw fasteners.
The complete assembly is of welded construction, with the welding to ASME
requirements. The materials and design are to ASME B31.1.
The completed water column undergoes pressure proof tests at 150% of duty pressure after
manufacture.
For further details on the water column dimensions, etc., refer to Figure 1.3 in Chapter 1, part
two of the manual.
Unit Description Hydrastep Pressure Parts
4-8 24675030
Hydrastep Pressure Parts Unit Specifications - Hydrastep
24675030 5-1
5
Unit Specifications - Hydrastep
5.1 ELECTRODES
Type 459600602 Complete with sealing gasket: Metaflex.
Screw in type M18 x 1.5
Insulator: Zirconia ceramic
Rating 120 bar (1740 psi) at 370C (698 F)
pH range 7-11
Hydrostatically tested to 180 bar (2610 psi) at ambient temp.
Type 459600802 Complete with sealing gasket: Metaflex.
Screw in type M18x 1.5
Insulator: PTFE or Teflon
Rating 50 bar (725 psi) at 260 C (500 F)
pH range 7-13.5
Hydrostatically tested to 155 bar (2247 psi) at ambient temp.
Type 246785A: Complete with ferrule sealing
25mm AF nut, thread 8
7” x 20 tpi UNEF form (Swagelok or Parker)
Insulator: High purity alumina ceramic
Rating 300 bar (4350 psi) max. at 560C (1040 F)
pH range 7-11
Hydrostatically tested at 450 bar (6525 psi) at ambient temp.
Note: For Super Critical Applications Only.
Type 246782A: Complete with ferrule sealing
22mm AF nut, thread ¾” x 20 tpi UNEF form (Swagelok or Parker)
Insulator: PTFE or Teflon
Rating 50bar (725 psi) at 260 C (500 F)
pH range 7-13.5
Hydrostatically tested at 155 bar (2247psi) at ambient temp.
Type 246784A: Complete with ferrule sealing
22mm AF nut, thread ¾” x 20 tpi UNEF form (Swagelok or Parker)
Insulator: PTFE or Teflon coated ceramic
Rating 300bar (4350 psi) at 260 C (500 F)
pH range 7-13.5
Hydrostatically tested at 450 bar (6525psi) at ambient temp.
Type 246781Z: Complete with ferrule sealing
22mm AF nut, thread ¾” x 20 tpi UNEF form (Swagelok or Parker)
Insulator: Zirconia ceramic
Rating 210 bar (3045 psi) at 370 C (698 F)
pH range 7-11
Hydrostatically tested at 315 bar (4568 psi) at ambient temp.
Unit Specifications - Hydrastep Hydrastep Pressure Parts Manual
5-2 24675030
5.2 WATER COLUMNS
Type Low Pressure: Rating 120bar (1740psi) at 343 C (650 F)
Type High Pressure: Rating 210bar (3045psi) at 370 C (698 F)
(Series III)
Type High Pressure: Rating 300bar (4350psi) at 560 C (1040 F)
(Super III)
Pt.3-1
Part 3
Hydrastep 2468CA, CB, CC & CD
Electronic Gauging System
Pt3-2
Hydrastep 2468 - Technical Manual Appendix A: CSA Approval
A-1
A
CSA Certified
A.1 GENERAL
All drawings in this manual are given here for planning purposes only. Before commencing with
implementation, reference should always be made to the current issue of the appropriate drawings. Contact
the factory for details.
No. Drawing Ref. Description
1. 24685037 Sheet 1 of 2 Hydrastep Control Diagram – CSA Certified Connections
2. 24685037 Sheet 2 of 2 Hydrastep Control Diagram – Associated Notes
Appendix A: CSA Approval Hydrastep 2468 - Technical Manual
A-2
Drawing 24685037 Sheet 1 of 2: Hydrastep Control Diagram, CSA Certified Connections
Hydrastep 2468 - Technical Manual Appendix A: CSA Approval
A-3
Drawing 24685037 Sheet 2 of 2: Hydrastep Control Diagram, Notes for Sheet 1
Appendix A: CSA Approval Hydrastep 2468 - Technical Manual
A-4
Hydrastep 2468
Operating Manual
24685034, Rev. AE
June 2011
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A
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We reserve the right to modify or improve the designs or specifications of product and services at any time without notice.
© 2011 Mobrey Ltd. All rights reserved.
International:
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