Ott Hydromet RLS252 Radar Level Sensor User Manual

Ott Hydromet GmbH Radar Level Sensor

user manual

English Operating instructionsRadar Level SensorOTT RLS
We reserve the right to make technical changes and improvements without notice.
3Table of contents1 Scope of supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Order numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Basic safety information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Installing the OTT RLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.1 Criteria for selecting a suitable mounting location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85.2 Notes on power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.3 Suitable cable types when using the RS-485 interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.4 Mounting the OTT RLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.5 Connecting the OTT RLS to any datalogger using an SDI-12 interface . . . . . . . . . . . . . . . . . . . 115.6 Connecting the OTT RLS to any datalogger using a 4 … 20 mA interface . . . . . . . . . . . . . . . . 125.7 Determining the maximum load resistance at the 4 … 20 mA interface . . . . . . . . . . . . . . . . . . 125.8 Notes on using the 4 … 20 mA interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.9 Note on using the RS-485 interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 SDI-12 commands and responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.1 Standard commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.2 Advanced SDI-12 commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Carrying out maintenance work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2110 Note about the disposal of old units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2211 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Annex A – Connecting the OTT RLS to LogoSens 2 or DuoSensusing an SDI-12 or RS-485 interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Annex B – Connecting the OTT RLS to LogoSens 2 or DuoSensusing a 4 … 20 mA interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Annex C – Dimensions of wall bracket/position of fixing bores . . . . . . . . . . . . . . . . . . . 30Annex D – Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Annex E – Radio Approval USA: Grant of Equipment Authorization . . . . . . . . . . . . . . . 32
1 Scope of supplyOTT RLS – 1 Radar sensor OTT RLS, two part swivel mount(consisting of device and wall brackets with 4 M8 Allen bolts)– 1 Installation kit (4 x wood screws 6 x 40 mm; 4 x plastic plugs S8)– 2 Double open-ended wrenches size 10 x 13– 1 Operating instructions– 1 Factory acceptance test certificate (FAT)2 Order numbersOTT RLS Radar sensor OTT RLS 63.107.001.9.2– Version 4: RS-485 + 4 … 20 mA interface– Version S: SDI-12 + 4 … 20 mA interfaceAccessories Connection cable 97.000.039.9.5– twisted-pair design– PVC, black– 2 x 2 x 0,5 mm2AWG 20Connection cable 97.000.040.9.5– twisted-pair design– PVC, black– 2 x 2 x 0,75 mm2AWG 19OTT RLS bridge mounting 63.105.025.3.2– Mounting aid for attaching the OTT RLS to a bridge– For side mounting– Height according to customer requirements– Distance to bridge according to customer requirementsAngle bracket 63.105.026.3.2– For attaching the OTT RLS bridge mounting from aboveOTT USB/SDI-12 Interface 65.050.001.9.2– For temporarily connecting OTT sensors to a PC withSDI-12 or RS-485 interface– Including 1 USB connection cable. USB connectortype A to USB type B; 3 m4
3 Basic safety informationRead these operating instructions before using the OTT RLS for the first time!Make yourself completely familiar with the installation and operation of theOTT RLS! Retain these operating instructions for later reference.The OTT RLS is used for contactless level measurement of surface waters. Onlyuse the OTT RLS in the manner described in these operating instructions! Forfurther information ➝ see Chapter 4, Introduction.Note all the detailed safety information given within the individual work steps.All safety information in these operating instructions are identified with thewarning symbol shown here.Never use the OTT RLS in areas where there is a danger of explosion. Forfurther information ➝ see Chapter 5, Installing the OTT RLS.Note that the electric installation of the OTT RLS may only be done by a professional. For further information ➝ see Chapter 5, Installing the OTT RLS.Protect the power supply connection with a fuse (2.5 ampere, blowing speed:fast). For further information ➝ see Chapter 5, Installing the OTT RLS.It is essential to comply with the electrical, mechanical and climatic specificationsgiven in the Technical Data section. For further information ➝ see Chapter 11,Technical data.Do not make any changes or retrofits to the OTT RLS. If changes or retrofits aremade, all guarantee claims are voided. Furthermore, the radio approval requiredfor its operation is void!Have a faulty OTT RLS inspected and repaired by our repair center. Nevermake any repairs yourself under any circumstances. For further information➝ see Chapter 8, Repair.Dispose of the OTT RLS properly after taking out of service. Never put theOTT RLS into the normal household waste. For further information ➝ see Chapter 10, Note about the disposal of old units.Federal Communications Commission (FCC) ApprovalNote: This equipment has been tested and found to comply with the limits for aClass A digital device, pursuant to part 15 of the FCC Rules. These limits aredesigned to provide reasonable protection against harmful interference when theequipment is operated in a commercial environment. This equipment generates,uses, and can radiate radio frequency energy and, if not installed and used inaccordance with the instruction manual, may cause harmful interference to radiocommunications. Operation of this equipment in a residential area is likely tocause harmful interference in which case the user will berequired to correct theinterference at his own expense.5
4 IntroductionThe OTT RLS radar sensor is used for contactless measurement of the levels of surface water.The OTT RLS is based on impulse radar technology. The transmitting antennatransmits short radar pulses in the FCC band 24.05 to 29.00 GHz. The separatereceiver antenna receives the pulses reflected from the water and uses them todetermine the distance between sensor and water surface: the time taken by theradar pulses from transmission to reception is proportional to the distancebetween sensor and water surface. The actual water level of the waterway is thencalculated automatically, if required, by the radar sensor. To do this, on initialstartup there is the possibility of inputting the relevant measurement mode and areference value.Three standardized electrical interfaces are available for connecting the OTT RLSto a datalogger or peripheral devices (depending on the version of the device):4 … 20 mA, SDI-12 and RS-485 (SDI-12 protocol).The radar sensor can be configured via the SDI-12 transparent mode of a data-logger or via the OTT USB/SDI-12 interface (accessory - SDI-12/RS-485 inter-face). When using the 4 … 20 mA interface, it is possible to scale the measure-ment output to a smaller measuring range.The transmission antenna has a beam width of approx. 12 °. The resulting sensorbeam can be seen in the depiction in Figures 2 and 3 and the table in Chapter 5.1.The OTT RLS includes a swivel mount that allows the sensor housing to be mount-ed parallel (longitudinal and lateral axis) with the water surface, even when thesensor is mounted on a slanted surface. A waterproof terminal area can be foundunder a removable screw cover for attaching the sensor cable.If the RS-485 interface is used, the length of cable between radar sensor and data - logger can amount up to 1000 meters · 3,300 ft. Using the SDI-12 interface, themaximum length of cable is 100 m · 330 ft.Provided that the unit has been mounted correctly according to the operatinginstructions, the complete radar sensor is flooding proof with IP 67 rating(diving bell principle).Fig. 1: Overview of radar sensor OTT RLS.Cover for transmission and receiving antenna (radom)SwivelmountRemovablescrew cover6
Fig. 3: Application example 2: Mounting the OTT RLS on anauxiliary construction, e.g. metalstand with mounting plate.OTT RLSSensor beamDistanceFig. 2: Application example 1: Mounting the OTT RLS on a bridge.The projection of the sensor beam ontothe water surface is virtually round.OTT RLSSensor beam Distance7
5 Installing the OTT RLS Caution: The electrical installation of the OTT RLS may only be undertaken byqualified persons (e.g. a specially trained electrician)!5.1 Criteria for selecting a suitable mounting locationPossible mounting locations are, for example, bridges and auxiliary con -structions directly above the waterway section to be measured.The minimum distance between lower edge of the sensor and water surface mustbe 0.8 m · 2.6 ft (dead area in which no useable measurement is possible).Select a mounting point high enough so that measurement is possible even withhigh water levels.The mounting point must be steady. Vibrations and movement of the mountingpoint must be avoided. Bridges are affected by movements of several centi -meters as a result of load changes and temperature movements. If pillars areavailable, the sensor can be mounted to a stable positioned pillar with a suit-able spacer.The water surface must be as smooth as possible in the area of the sensorbeam. Avoid turbulent areas, areas where foam is created, surge areas andwaterway sections where obstructions or bridge piers cause changes in thewater level. The measurement result cannot be used if there is ice or snow onthe water surface!Choose a mounting location that does not become dry at low water levels.Stations subject to very rapid changes in water level are not suitable. TheOTT RLS averages its measurement result over a measuring time of approx.20 seconds.The area within the sensor beam (see Figures 2 and 3) must be completely freeof obstructions. Table for approximating the size of the sensor beam:Distance DiameterOTT RLS – sensor beamwater surface5 m 16.5 ft 1.06 m 3.5 ft10 m 33.0 ft 2.12 m 7.0 ft15 m 49.0 ft 3.19 m 10.5 ft20 m 66.0 ft 4.25 m 14.0 ft25 m 82.0 ft 5.31 m 17.5 ft30 m 98.0 ft 6.38 m 21.0 ft35 m 115.0 ft 7.44 m 24.5 ftThe diameters given are minimum sizes. Where possible, select an area free ofobstruction that is clearly larger.Avoid large metal surfaces near the sensor beam (reflections from these sur facescan distort the measurement result).The climate specifications in the technical data must be kept to at the mountinglocation.Stilling wells are unsuitable as a mounting location.The OTT RLS cannot be used to measure wave height.WARNING Danger of explosion due to spark formation and electrostaticdischargeThe use of the OTT RLS in explosive atmospheres can lead to the danger of ignitionof this atmosphere. An explosion resulting from this involves the risk of very severematerial and personal damage.Never operate the OTT RLS in explosive areas (e.g. in sewers). The OTT RLSis not equipped with EX-protection (EXplosion protection)!8
5.2 Notes on power supplyThe OTT RLS requires a power supply of 9.6 … 28 V direct current of type12/24 V DC (e.g. a battery or mains connection with galvanically isolated lowsafety voltage).The OTT RLS is immediately ready for operation after connecting the power supply.Warning:Secure the power supply cable (terminal 1 of the screw terminal strip) with afuse (2.5 ampere, reaction time: fast)!When using solar panels, we recommend the use of an overvoltage protectiondevice.5.3 Suitable cable types when using the RS-485 interfaceThe maximum length of the connecting cable is 1,000 m · 3,300 ft. Recommendedcable type: Twisted-pair cable; unshielded (alternatively: shielded). The wiresintended for the power supply can be twisted pair, but do not have to be.Types of OTT cable which can be used (see accessories)up to 500 m · 1,650 ft length of connecting cable: 2 x 2 x 0,5 mm2;approx. AWG 20 (flexible wires)500 to 1000 m · 1,650 to 3,300 ft length of connecting cable:2 x 2 x 0,75 mm2; AWG 19 (flexible wires)5.4 Mounting the OTT RLSWarning: Ensure no moisture enters the connection area when the screw coveris open! If the connection area gets moist there is increased danger of corrosion ofthe electric contacts.Assembling the swivel mount (see also Annex C)Mounting surface: concrete or masonryMake four holes (Ø 8 mm · 5/16"/ 43 mm · 1.7 ft deep) using a hammerdrill (use wall bracket as a template).Insert the four plastic plugs supplied into the holes.Attach the wall bracket using the four wood screws supplied.Insert housing bracket (without sensor) into wall bracket and lightly tighten thehex bolts A (see fig. 5).Mounting surface: auxiliary construction, e. g. metal stand with mounting plateDrill four holes (Ø 7 mm · 9/32") in the mounting plate (use wall bracket as atemplate).Attach the wall bracket e. g. using four hex bolts (M6) and nuts.Insert housing bracket (without sensor) into wall bracket and lightly tighten thehex bolts A (see fig. 5).Preparing the cable glandWith a cable diameter of 7.0 … 11.0 mm, remove inlet: Insert screwdriververtically into the seam and lever out the inlet. See Figure 4.Insert the connecting cable.9
Mounting the radar sensorRemove screw cover.Insert connecting cable from OTT RLS to datalogger through cable gland.Remove insulation from connecting cable.With flexible wires: put end caps on the wires.Connect the connecting cable to the terminal block. Take note of Chapters 5.5and 5.6 and Appendices A and B. If required, the terminal strip can be pulledout for connecting.Retighten connecting cable as necessary.Tighten the tightening nut of the cable gland (torque for tightening nut: 6 Nm).Screw on the screw cover and tighten firmly by hand.Insert sensor into housing bracket and lightly tighten the hex bolts B (see fig. 5). Align the housing parallel (longitudinal and lateral axis) with the water surfaceusing a bubble level.Tighten the hex bolts B (housing shell) carefully (see fig. 5).Tighten the hex bolts A (wall/housing brackets) carefully (see fig. 5).Check alignment of the OTT RLS once more.Fig. 4: OTT RLS – connection area.Clamping range of the cable gland:with inlet ➝ 4.0 to 7.0 mmwithout inlet ➝ 7.0 to 11.0 mmRemovablescrew coverTightening nutCable glandScrewterminal stripSensorCable glandInletConnectingcable4 … 20 mA +4 … 20 mA –GNDRS-485 B *RS-485 A *SDI-12 DATA* SDI-12 protocol via physicalRS-485 interface (for connecting toOTT DuoSens and OTT LogoSens 2)542 3176+9.6 … 28 VScrew terminal strip(pulled out)10
Warning: The alignment of the sensor parallel to the water surface must be carried out as accurately as possible!➝Deviation from the parallel alignment leads to a linearity error.➝Incorrect alignment of > 4 ° can lead to a function failure of the OTT RLS(depending on the other operating parameters such as distance betweenlower sensor edge and water surface).5.5 Connecting the OTT RLS to any datalogger using an SDI-12interfaceConnect the OTT RLS to an SDI-12 input of the datalogger. Follow the datalog-ger handbook as you do this. Refer to Figure 6 for the connection assignmentsof the OTT RLS. The maximum length of the connecting cable is 100 m · 330 ft.Recommended wire cross-section: 0.5 mm2· AWG 20. With separate voltagesupply and point-to-point connection (no SDI-12 bus operation) a cable lengthof up to 300 m · 985 ft is possible.You will find the SDI-12 commands for the OTT RLS in Chapter 6, SDI-12 com-mands and responses.Fig. 6: Connecting the OTT RLS to anydatalogger using an SDI-12 interface.(Standard SDI-12 wiring viathree-wire connecting cable).+12 VSDI-12 GNDSDI-12 DATA542 3176RLSFig. 5: OTT RLS – rotationrange of swivel mount.max. ±90 °Hexbolt A Hex bolt BWallbracket Housing bracketmax. ±15 °11
5.6 Connecting the OTT RLS to any datalogger usinga 4 … 20 mA interfaceConnect the OTT RLS to a 4 … 20 mA input of the datalogger. Follow the data-logger handbook when doing this. Refer to Figure 7 for the connection assign-ments of the OTT RLS. The maximum connecting cable length/recommendedwire cross-section: depending on the amount of voltage supply and the size ofthe burden (load resistor). Please note that the ohmic resistance of the connect-ing cable together with the eventually existing burden do not exceed the max.allowed load resistance (see Chapter 5.7)!Caution: the 4 … 20 mA interface of the OTT RLS is passive. If needed the sup-ply for the current loop must be injected by wire-linking the supply voltage.Tipp: To connect the OTT RLS using the 4 … 20 mA interface, a 4-wire cable isrequired. If the OTT RLS is also to be configurable via SDI-12 commands, ➝use5-wire (cable length up to 100 m) or 6-wire cable (cable length up to 1000 m).5.7 Determining the maximum load resistance at the 4 … 20 mAinterfaceThe load resistance (burden + ohmic resistance of the connection cable) connectedto the OTT RLS must not exceed a specific maximum value. This value depends onthe level of the supply voltage of the OTT RLS. If the load resistance is greater, theoutput current can no longer be evaluated. Smaller load resistances are allowed.Read off the maximum load resistance for your power supply from the follow-ing diagram.Example: Power supply 18 volt ➝max. load resistance 450 ohm.The OTT RLS delivers an output current corresponding to the measured valuefor a load resistance of up to 450 ohm.Dimension the connected electrical circuit accordingly. Check the input resis-tance of the connected peripheral device for this purpose.Fig. 7: Examples for connecting theOTT RLS to any datalogger via the4 … 20 mA interface.Left: supplying the loopcurrent from the datalogger.Right: supplying the loop current to theOTT RLS supply voltage using wire bridges.+9,6 … 28 VGND4 … 20 mA +4 … 20 mA –GND4 … 20 mA +4 … 20 mA –542 3176RLS+9,6 … 28 V542 3176RLS12
5.8 Notes on using the 4 … 20 mA interfaceSwitching behaviour of the 4 … 20 mA interfaceAfter switching on the supply voltage, it takes approx. 20 seconds until theloop current takes on a value proportional to the water level. (In the first20 seconds, the loop current is between 3 and 4 mA.) Afterwards, the radar sensor updates the loop current every 20 seconds.Caution: The 4 … 20 mA interface cannot be used parallel to the SDI-12 orRS-485 interfaces. (Exception: temporary configuration of the OTT RLS withSDI-12 commands.)5.9 Note on using the RS-485 interfaceThe RS-485 interface can only be used with an OTT datalogger. In this case, thetransmission protocol via the physical RS-485 interface is the SDI-12 protocol.Connect OTT RLS via the RS-485 interface to the OTT LogoSens/DuoSens ➝seesee Appendix A, version B.10 15 20 25 30 UV1000200300400500600700800RΩ9001000ExampleFigure 8: Diagram to determinethe maximum load resistance as a function of the power supply.Minimum power supply: 9.6 VMaximum power supply: 28 VResistor tolerance: 0.1 %/15 ppm(burden = load resistor).13
6 SDI-12 commands and responses6.1 Standard commandsAll SDI-12 standard commands (SDI-12 version 1.1) are implemented in the OTT RLS: The following SDI-12 standard com-mands are relevant for the operation of the OTT RLS:Command Response Descriptiona! a<CR><LF> Confirmation activea– sensor address; factory setting = 0aI! allccccccccmmmmmm……vvvxxxxxx<CR><LF>Send identificationa– sensor addressll – SDI-12 protocol versioncccccccc – manufacturer's identification (company name)mmmmmm – sensor identificationvvv – sensor version (here firmware version)xxxxxx – additional identification (here serial number)OTT RLS response = 011OTT HACH RLS110xxxxxxaAb! b<CR><LF> Change sensor addressa– old sensor addressb– new sensor address?! a<CR><LF> Query sensor address a– sensor addressaM! 1)atttn<CR><LF>and after a max. of 25 secondsa<CR><LF>Start measurementa– sensor addressttt – time in seconds until the sensor hasdetermined the measurement result OTT RLS response = 025 secondsn– number of measured valuesOTT RLS response = 2a<CR><LF> – service requestaD0! a<value1><value2><CR><LF> Send data (after aM!)a– sensor address<value1>– level/distance value:pbbbb.eee [m]2)pbbbbb [cm]2)pbbbbb.ee [ft]2)p– sign (+,–)b– digit (before the decimal point);output without leading zeroes!e– digit after the decimal point;output in the case of invalid measurementvalue: +99999999 (can be changed withadvanced command aOSI!)<value2>– status of the last measurement;for details, see response to command aM1!aMC! 1) atttn<CR><LF>and after a max. of 25 secondsa<CR><LF>Start measurement and request CRC (Cyclic RedundancyCheck). For details, see command aM!. The response to thefollowing aD0! command is extended by a CRC value:a<value1><value2><CRC><CR><LF>aM1! 1) atttn<CR><LF>and immediately afterwardsa<CR><LF>Query status of the last measurementa– sensor addressttt – time in seconds until the sensor makes thestatus available; OTT RLS response = 000n– number of measured valuesOTT RLS response = 2a<CR><LF> – service request1) do not use this command if OTT RLS is connected to a datalogger via the 4 … 20 mA interface! OTT RLS would consequently interrupt the continuous measuringoperation which is needed for the 4 … 20 mA interface.2) Dependent on the units set (advanced command aOSU<value>!)14
More information on the SDI-12 standard commands can be found in the document SDI-12; A Serial-Digital Interface Standardfor Microprocessor-Based Sensors; Version 1.1 (see Internet page www.sdi-12.org).6.2 Advanced SDI-12 commandsAll advanced SDI-12 commands begin with an "O" for OTT. With these commands, it is possible to configure the OTT RLSusing the transparent mode of a datalogger or with the OTT USB/SDI-12 interface (accessory).Command Response DescriptionQuery firmware versionaOOV! accccccc<CR><LF> Query the firmware version of the OTT RLS.a– sensor addressccccccc – firmware version. Example: V1.10.04 … 20 mA interface – set/read units for measurementsaOPF<value>!aOPFa<value><CR><LF>a<value><CR><LF>Set units for commands aOPA<value>! andaOPB<value>!.Read unit for commands aOPA<value! andaOPB<value>!.a– sensor address<value> – +0 = m+1 = cm+2 = ftSDI-12-/RS-485 interface – set/read units for measurementsaOSU<value>!aOSU!a<value><CR><LF>a<value><CR><LF>Set units for commands aM!; aMC!; aOAB<value>! andaOAC<value>!.Read unit for commands aM!; aMC!; aOAB<value>! andaOAC<value>!a– sensor address<value> – +0 = m+1 = cm+2 = ftCautionChanging the unit deletes any set reference or offset value!Command Response DescriptionaD0! a<value1><value2><CR><LF> Send data (after aM1!)a– sensor address<value1>– status of the last measurement+0 = measured value O.K.+2 = no target recognised+4 = internal error ➝ device fault.See Chapter 8, Repair+8 = variance of individual measurements toolarge+16 = SDI-12 interface interruption (breach ofthe SDI-12 interface protocol, e.g. com-munication with the SDI-12 interfacebetween commands aM! and aD0!)+32 = internal error (temperature calibrationvalues missing) ➝ device fault. SeeChapter 8, Repair<value2>– signal-to-noise ratio in dB. Value ≥ 15 dB =good signal quality (well-chosen mountinglocation and parallel alignment)aMC1! atttn<CR><LF>and immediately afterwardsa<CR><LF>Query the status of the last measurement and request CRC(Cyclic Redundancy Check). For details, see command aM!.The response to the following aD0! command is extended bya CRC value: a<value1><value2><CRC><CR><LF>15
Command Response DescriptionSet/read measurement mode level or distance measurementaOAA<value>!aOAA!a<value><CR><LF>a<value><CR><LF>Set measuring modeRead out measuring modea– sensor address<value>– +0 = measuring mode Level measurement acti-vated (water level related to a level zero)+1 = measuring mode Distance measurementactivated (distance of OTT RLS ↔watersurface)Factory setting = +1CautionIf entries have been made before changing the measuringmode for the parameters aOAB<value>!, aOAC<value>!,aOPA<value>! or aOPB<value>!, these must be input again!There is no automatic conversion of the parameters entered.Set/read error indicatoraOSI<value>!aOSI!a<value><CR><LF>a<value><CR><LF>Set error indicatorRead error indicatora– sensor address<value> – error indicator that the OTT RLS outputsan invalid measurementpbbbbbbbbp– sign (+,–)b– digitValue range: –99999999 … +99999999Factory setting = +99999999Set/read 4 … 20 mA interface – operating status (activated/deactivated)aOPC<value>aOPC!a<value><CR><LF>a<value><CR><LF>Set operating statusRead operating statusa– sensor address<value> – pb; factory setting = +1p– sign (+)b– digit+0 = interface deactivated+1 = interface activatedUse: the command aOPC+1! is helpful, if e.g. an aM! com-mand unintended has interrupted the continuous operationwhich is needed for the 4 … 20 mA interface.4 … 20 mA interface – setting/reading the lower limitaOPA<value>!aOPA!a<value><CR><LF>a<value><CR><LF>Set lower limitRead lower limita– sensor address<value> – pbbbb.eee [m] *– pbbbb [cm] *– pbbbb.ee [ft] *p– sign (+,–)b– digit (before the decimal point)e– digit after the decimal pointInput/output without leading zeroes!Value range: –9999.999 … +9999.999 *Factory setting = +0.000* Dependent on the units set (aOPF<value>!)NoteIf the units are subsequently changed (aOPF<value>!), theOTT RLS resets the set limit to the factory setting.16
Fig. 9: Scale the measured valueoutput of the 4 … 20 mA interfacedown to a smaller range.10 m · 33 ft=^ 4 mA(lower limit)15 m · 49 ft=^ 20 mA(upper limit)measuredvalue outputscaled to5 meters · 16 ftvariation ofwater levelFigure is not true to scale0 m · 0 ft =^ 4 mAmin. distance: 0,8 m· 2.6 ft (=^ 4.37 mA)35 m · 115 ft =^ 20 mAwith scalingmeasuredvalue outputwithout scalingCommand Response Description4 … 20 mA interface – setting/reading the upper limitaOPB<value>!aOPB!a<value><CR><LF>a<value><CR><LF>Set upper limitRead upper limita– sensor address<value> – pbbbb.eee [m] *– pbbbb [cm] *– pbbbb.ee [ft] *p– sign (+,–)b– digit (before the decimal point)e– digit after the decimal pointInput/output without leading zeroes!Value range: –9999.999 … +9999.999 *Factory setting = +0.000* Dependent on the units set (aOPF<value>!)NoteIf the units are subsequently changed (aOPF<value>!), theOTT RLS resets the set limit to the factory setting.With the commands setting/reading the lower/upper limit you can scale the available measuring range of an OTT RLS to asmaller range. Where you do not require the whole measuring range, this has the advantage that a higher resolution for the4 … 20 mA interface can be achieved. Example: 16 mA measurement span stands for 5 m · 16 ft of water level changeavailable (e.g. lower limit = +10,000 m · +33,00 ft; upper limit = +15,000 m · +49.00 ft; see Fig. 9).17
Command Response DescriptionSDI-12-/RS-485 interface – set/read offset for level/distance measurementaOAB<value>!aOAB!a0251<CR><LF>and after a max. of 25 secondsa<CR><LF>a<value><CR><LFSet offset valueRead offset valuea– sensor address<value> – pbbbb.eee [m] *– pbbbb [cm] *– pbbbb.ee [ft] *p– sign (+,–)b– digit (before the decimal point)e– digit after the decimal pointa<CR><LF> – service requestInput/output without leading zeroes!Value range: –9999.999 … +9999.999 *Factory setting = +0.000With this command, you can add a linear offset (positive/negative) to a level/distance measurement. After setting theoffset value, the OTT RLS automatically starts a measure-ment. After receiving the service request, check the measu-red value with command aD0!. If input is unsuccessful, theradar sensor replies with a new service request.CautionThis command overwrites any set reference value.ExampleMeasurement = +10,040 mOffset = –0,200 mOutput = +9,840 mNoteIf the units are subsequently changed (aOSU<value>!), theOTT RLS resets the set offset value to the factory setting.SDI-12-/RS-485 interface – set/read reference value for the offset for level/distance measurementaOAC<value>!aOAC!a0251<CR><LF>and after a max. of 25 secondsa<CR><LF>a<value><CR><LF>Set reference valueRead reference valuea– sensor address<value> – pbbbb.eee [m] *– pbbbb [cm] *– pbbbb.ee [ft] *p– sign (+,–)b– digit (before the decimal point)e– digit after the decimal pointa<CR><LF> – service requestInput/output without leading zeroes!Value range: –9999.999 … +9999.999 *Factory setting = +0.000With this command, you can establish a reference to a levelzero, for example, by entering a reference value forlevel/distance measurement.* Dependent on the units set (aOSU<value>!)18
Command Response DescriptionAfter setting the reference value, the OTT RLS automaticallystarts a measurement. After receiving the service request,check the measured value with command aD0!. After anunsuccessful entry, the radar sensor replies with a new service request.CautionThis command overwrites any set offset value.ExampleMeasurement = +2,100 mReference value = +1,500 mOutput = +1,500 m(offset calculated by the OTT RLS and applied to all othermeasured values = +0.600 m)NoteIf the units are subsequently changed (aOSU<value>!), theOTT RLS resets the set reference value to the factory setting.19
7 Carrying out maintenance workThe OTT RLS radar sensor is almost maintenance free. No setting or calibrationwork is necessary. There are likewise no parts that need replacing regularly.Carry out the following maintenance work at regular frequencies based on thelocal circumstances:Check the OTT RLS for dirt (e.g. thick, dewy spider's webs or insect nests canlead to impairment of the measured results). In this case, carefully clean thesensor (if necessary use commercial, gentle and non-erasing cleaners and asoft sponge). At the same time, ensure that the setting of the swivel mount doesnot change.Check for obstructions in the measurement beam (for example, for flotsam orbranches of trees and bushes growing into this area). In this case, remove allobstructions.Check the plausibility of the measured values by comparing with a second sensoror with a staff gauge.Warning: Never open the housing of the OTT RLS (exception: connection area)!There are no adjustment or operating elements inside the housing.8 Repair With a device defect, use Chapter 9, Troubleshooting to see if you can resolvethe problem yourself. In case of device defects, please contact the repair center of OTT:OTT Hydromet GmbH Repaircenter Ludwigstrasse 1687437 Kempten · GermanyTelephone +49 831 5617-433Fax +49 831 5617-439repair@ott.comWarning: Only have a defective OTT RLS checked and repaired by the OTTrepair center. Never make any repairs yourself under any circum-stances. Any repairs or attempted repairs carried out by the cus-tomer will result in the loss of any guarantee rights.20
9 TroubleshootingSensor does not respond to the SDI-12 interfaceFuse in the power supply input side defective? ➝Replace fuse.Sensor correctly connected to a datalogger with SDI-12 input (master)? ➝Correct connection assignment.Polarity of the power supply reversed? ➝Correct connection assignment.Power supply < 9.6 V or > 28 V? ➝Correct level of voltage supplied (check the length and cross-section of theconnection cable).Is the power supply direct current? ➝Only operate sensor with direct current.4 … 20 mA signal not presentSensor correctly connected to a datalogger or peripheral device to 4 … 20 mAinput (check polarity)? ➝Correct connection assignment.4 … 20 mA current loop correctly supplied through datalogger or OTT RLS(internal/external supply)? ➝Correct connection assignment. Measured value varies or is not presentSensor (front plate) dirty? ➝Carefully clean the sensor; see Chapter 7, Carrying out maintenance workObstruction in the measurement beam? ➝Remove obstructions.Sensor aligned at right angles to the water surface? ➝Correct sensor alignment.Mounting location of the sensor steady (e.g. bridge movement)? ➝Optimize mounting location.Large metal surfaces near the sensor beam (e.g. piling)? ➝Optimize mounting location.Status messages/output of interfacesSDI-12 1) 4 … 20 mA Status message/output+0 measured value measured value OK+2 3.0 mA no target recognized+4 3.1 mA internal error ➝device defect; see Chapter 8, Repair+8 3.2 mA variance of individual measurements too large+16 3.3 mA SDI-12 interface break (infringement of SDI-12 inter-face protocol, e.g. communication via SDI-12 interfacebetween the commands aM! and aD0!)– 3.4 mA value below or above measuring range+32 3.5 mA internal error ➝device defect; see Chapter 8, Repair1) response to commands aM!, aM1! and aD0!21
10 Note about the disposal of old unitsDispose of the OTT RLS properly after taking out of service.Observe the regulations valid in your country for the disposal of electronicdevices.Never put the OTT RLS into the normal household waste.Used materialssee Chapter 11, Technical Data22
11 Technical DataMeasuring range 0.8 … 35 m 80 … 3500 cm 2.6 … 115 ftResolution SDI-12 interface 0.001 m 1 cm 0.01 ftAccuracy (SDI-12) 1)0.8 … 2 m · 2.6 … 6.6 ft ±10 mm · ±0.03 ft2 … 30 m · 6.6 … 98.5 ft ±3 mm · ±0.01 ft30 … 35 m · 98.5 … 115 ft ±10 mm · ±0.03 ftAverage temperature coefficient 0.01 % of full scale/10 K(range: –20 …+60 °C · –4 … +140 °F)Accuracy (4 … 20 mA) 1) ±0.1% of full scaleAverage temperature coefficient (at +20 °C · +68 °F) 10 ppm of full scale/KMeasuring time 20 secondsPower supply 9.6 … 28 V DC, typ. 12/24 V DCPower consumption 2)Measurement operation < 140 mW (< 12 mA at 12 V)Rest mode < 1 mW (< 0.05 mA at 12 V)Interfaces 4 … 20 mA (measurement update every 20 seconds); SDI-12;RS-485, two-wire (SDI-12 protocol)Beam angle of antenna 12 ° (±6 °)Transmission frequency 26 GHz (puls radar)Transmission power < 5 mWMaterialsHousing ASA (UV-stabilized ABS) Radom (front plate) TFM PTFE Mounting 1.4301 (V2A)Weight (including mounting) approx. 2.1 kg · 4.63 lbCable gland sealing rangewith inlet (min. Ø … max. Ø) 4.0 … 7.0 mm · 0.16 … 0.28"without inlet (min. Ø … max. Ø) 7.0 … 11.0 mm · 0.28 … 0.43"Connection capacity of screw terminal stripSolid conductor 0.25 … 2.5 mm2· AWG 24 to 12Wire with end cap and plastic collar 0.25 … 1.5 mm2· AWG 24 to 16Terminal assignment screw terminal stripTerminal 1 power supplyTerminal 2 RS-485 BTerminal 3 RS-485 ATerminal 4 4 … 20 mA –Terminal 5 4 … 20 mA +Terminal 6 SDI-12 DATATerminal 7 GNDRotation range of swivel mountLateral axis ±90 °Longitudinal axis ±15 °Type of protection at horizontal installation IP 67 (submersion depth max. 1 m · 3.3 ft;Submersion duration max. 48 h)Dimensions L x W x H 222 mm x 152 mm x 190 mm · 8.74" x 5.98" x 7.48"Temperature rangeOperation –40 … +60 °C · –40 … +140 °FStorage –40 … +85 °C · –40 … +185 °FRelative humidity 0 … 100 % 3)1) at +20 °C · +68 °F ambient temperature: 1013 mbar · 29.9 inHg air pressure; 45 % to 65 % relative humidity; ideal reflector; without interfering reflectorin the sensor beam2) Power consumption of OTT RLS with SDI-12, RS-485 or externally supplied 4 … 20 mA interface3) Condensation on the front plate of the antenna (Radom) can disturb measuring accuracy23
Performance classification in accordance with DIN EN ISO 4373Measurement reliability Performance class 1Temperature range Temperature class 1Relative humidity Class 1Approval for Short Range Device; USA FCC 47 CFR Part 1524
Annex A – Connecting the OTT RLS via SDI-12 or RS-485 interface to LogoSens 2or DuoSensThere are two ways to connect the OTT RLS:Method A: using the SDI-12 interface(protocol and physical interface: SDI-12).Method B: using the RS-485 interface(SDI-12 protocol via physical RS-485 interface).Recommendation: method B (longer range, more resistant to faults)Method A: Connecting the OTT RLS via the SDI-12 interface (protocol and physical interface: SDI-12). The maximum length of the connecting cable is 100 m ·330 ft. Recommended wire cross-section: 0.5 mm2· AWG 20:Connect the OTT RLS to the LogoSens 2 Station Manager or to the DuoSensCompact Datalogger as shown in Figure 10. Take note of the operating instruc -tions for the LogoSens 2/DuoSens.Fig. 10: Connecting the OTT RLSto LogoSens 2 or DuoSens usingan SDI-12 interface.The letters above the screw terminal stripidentify the possible connections on theLogoSens 2/DuoSens.SDI-12InputA … R431 2 LogoSens 2SDI-12InputA431 2 DuoSensRLS542 3176RLS542 3176+9.6 … 28 V+9.6 … 28 V25
Method B: Connect OTT RLS using the physical RS-485 interface (SDI-12 protocolvia physical RS-485 interface). Refer to Chapter 5.3 for the maximum connectingcable length and the recommended wire cross-section:Connect the OTT RLS to the LogoSens 2 Station Manager or to the DuoSensCompact Datalogger as shown in Figure 11. Take note of the operatinginstruct ions for the LogoSens 2/DuoSens.Fig. 11: Connecting the OTT RLS to Logo-Sens 2 or DuoSens using an RS-485 inter-face (SDI-12 protocol).The letters above the screw terminalstrip identify the possible connectionson the LogoSens 2/DuoSens.When connecting the OTT RLS to theLogoSens 2, use a 120 Ohm terminator(order number: 96.300.205.9.5).120 OhmterminatorRS-485Input RS-485InputRLS RLS542 3176542 3176+9.6 … 28 V+9.6 … 28 VA … R431 2 LogoSens 2A431 2 DuoSens26
Configuring the LogoSens 2/DuoSens for the OTT RLS with SDI-12interfaceCreate a LogoSens 2/DuoSens channel with SDI-12 Master or OTT SDI RS485function block (serial sensors tab).Apply the following settings:Terminal block LogoSens 2: A … R DuoSens SDI-12 Master: A 3-4 (specified) DuoSens OTT SDI RS485: A 1-2 (specified)terminal block used (screw terminal strip) of theLogoSens 2/DuoSens.Slave address SDI-12 bus address. Each address may only beallocated once to an SDI-12 bus feed!(Checking/setting: see operating instructionsLogoSens 2/ DuoSens, Chapter SDI-12 transparentmode; alternatively with OTT USB/SDI-12 inter-face)Factory setting of the OTT RLS: 0Value no. 1Identifies which value from the OTT RLS is recordedin this channel. (The OTT RLS determines two valueswith the command aM!: measurement and statusinformation.)Measurement mode M! (SDI-12 measurement command for this channel)Allocation of the status information to a virtual terminal.In the relevant Channel function blocks, adjust the required units and number ofdigits after the decimal place (m: 3; cm: 0; ft: 2; status information: 0).Note:To record the measurements and status information of an OTT RLS, two channelsin the LogoSens 2/DuoSens are thus necessary. The first channel contains thefunction block SDI-12 Master or OTT SDI RS485 as the input signal. The secondchannel contains a function block Virtual Sensor (V02) as the input signal. Ifthe recording of status information is not required, no entry is necessary in theValue no./Virtual terminal ID field.The measuring mode M1! supplies extended status information. If required, thiscan also be recorded in an additional channel with function block SDI-12 Master/OTT SDI RS485.You will find further information on the used SDI-12 commands and responsesin Chapter 6, SDI-12 commands and responses.Please note: The OTT PLS makes the measurement results available a maximumof 25 seconds after the SDI-12 command aM!!Fig. 12: Adjusting the operating parametersof the LogoSens 2/DuoSensSDI-12 Master function block.The function block OTT SDI RS485is set in the same way.Value no./Virtual terminal ID27
Annex B – Connecting the OTT RLS to LogoSens 2 or DuoSens using a4 … 20 mA interfaceConnect the OTT RLS to the LogoSens 2 Station Manager or to the DuoSens Compact Datalogger as shown in Figure 13 and 14. Take note of the operatinginstructions for the LogoSens 2/DuoSens. Maximum connecting cable length/recommended wire cross-section: depending on the amount of voltage supplyand the size of the burden (load resistor). Please note that the ohmic resistanceof the connecting cable together with the eventually existing burden do notexceed the max. allowed load resistance (see Chapter 5.7)!4 … 20 mAInputC … F*431 2542 3176 DuoSensRLS* only with a DuoSens with analog extension+9.6 … 28 VFig. 14: Connecting the OTT RLS toDuoSens using a 4 … 20 mA interface.The letters above the screw terminalstrip identify the possible connectionson the DuoSens.4 … 20 mA InputA … R431 2 LogoSens 2RLS542 3176100 Ohm load resistor+9,6 … 28 VFig. 13: Connecting the OTT RLS toLogoSens 2 using a 4 … 20 mA interfaceUse the 100 Ohm OTT resistor(order number: 55.550.800.9.5).The letters above the screw terminalstrip identify the possible connectionson the LogoSens 2.28
Configuring the LogoSens 2/DuoSens for OTT RLS with 4 … 20 mAinterfaceCreate a LogoSens 2/DuoSens channel with function block I 4-20 mA(LogoSens 2) or U/I/Pt100/… (DuoSens) (Analog sensors tab).Apply the following settings:Terminal block LogoSens 2: A … RDuoSens: C … Fterminal block used (screw terminal strip)of the LogoSens 2/DuoSens.Set to I 4-20 mA ext.Sensor lag time (s) switches on the LogoSens 2/DuoSens input1 second before the actual measurementprocessif required: record error codes on rangeoverflownot required with an OTT RLSInsert a 2-point scaling function block into this channel and adjust the relatingdistance values for the outputed current values (e. g. Point 1: 4 ➝0; Point 2:20 ➝35 m · 115 ft). This function also enables the referencing to a level zero.In the Channel function block, set the unit and number of digits after the decimalplace (m: 3; cm: 0; ft: 2)..Auxiliary sensor supply viarelay contact at terminal block(only for LogoSens 2)□Error code if range overflowMeasurement mode(only with DuoSens)Fig. 15: Setting operating parameters of theLogoSens 2 I 4-20 mA function block.The DuoSens function block U/I/Pt100/…is set in the same way.29
Annex C – Dimensions of wall bracket/position of fixing bores35 mm · 1.38"137 mm · 5.39"67.5 mm · 2.66"152 mm · 5.98"12 mm0.47"4 0.16"70.28"8.5 0.33"23 mm0.91"222 mm · 8.74"Ø17 mm · 0.67"30
Annex D – Declaration of Conformity31
Annex E – Radio Approval USA: Grant of Equipment Authorization32
OTT Hydromet GmbHLudwigstrasse 1687437 Kempten · GermanyPhone +49 831 5617-0Fax +49 831 5617-209info@ott.com · www.ott.comDocument number63.107.001.B.E 01-0714

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