Fluke Thermometer 189 Users Manual

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Model 187 & 189

True RMS Multimeter

Users Manual

August 2000, Rev.2, 6/02
© 2000, 2002 Fluke Corporation. All rights reserved. Printed in U.S.A.
All product names are trademarks of their respective companies.

Lifetime Limited Warranty
Each Fluke 20, 70, 80, 170 and 180 Series DMM will be free from defects in material and workmanship for its lifetime. As used herein,
“lifetime” is defined as seven years after Fluke discontinues manufacturing the product, but the warranty period shall be at least ten years from
the date of purchase. This warranty does not cover fuses, disposable batteries, damage from neglect, misuse, contamination, alteration,
accident or abnormal conditions of operation or handling, including failures caused by use outside of the product’s specifications, or normal
wear and tear of mechanical components. This warranty covers the original purchaser only and is not transferable.
For ten years from the date of purchase, this warranty also covers the LCD. Thereafter, for the lifetime of the DMM, Fluke will replace the
LCD for a fee based on then current component acquisition costs.
To establish original ownership and prove date of purchase, please complete and return the registration card accompanying the product, or
register your product on http://www.fluke.com. Fluke will, at its option, repair at no charge, replace or refund the purchase price of a defective product purchased through a Fluke authorized sales outlet and at the applicable international price. Fluke reserves the right to charge
for importation costs of repair/replacement parts if the product purchased in one country is sent for repair elsewhere.
If the product is defective, contact your nearest Fluke authorized service center to obtain return authorization information, then send the
product to that service center, with a description of the difficulty, postage and insurance prepaid (FOB Destination). Fluke assumes no risk
for damage in transit. Fluke will pay return transportation for product repaired or replaced in-warranty. Before making any non-warranty
repair, Fluke will estimate cost and obtain authorization, then invoice you for repair and return transportation.
THIS WARRANTY IS YOUR ONLY REMEDY. NO OTHER WARRANTIES, SUCH AS FITNESS FOR A PARTICULAR PURPOSE, ARE
EXPRESSED OR IMPLIED. FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL
DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY. AUTHORIZED RESELLERS ARE
NOT AUTHORIZED TO EXTEND ANY DIFFERENT WARRANTY ON FLUKE’S BEHALF. Since some states do not allow the exclusion or
limitation of an implied warranty or of incidental or consequential damages, this limitation of liability may not apply to you. If any provision of
this warranty is held invalid or unenforceable by a court or other decision-maker of competent jurisdiction, such holding will not affect the
validity or enforceability of any other provision.
Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.
2/02

Fluke Europe B.V.
P.O. Box 1186
5602 BD Eindhoven
The Netherlands

Table of Contents

Chapter
1

Title

Page

Before You Start .......................................................................................................... 1-1
Safety Information.......................................................................................................... 1-1
Contacting Fluke............................................................................................................ 1-1
Symbols ......................................................................................................................... 1-4

Getting Acquainted...................................................................................................... 2-1
Introduction....................................................................................................................
Turning the Meter On.....................................................................................................
Battery Considerations ..................................................................................................
Automatic Power Off .................................................................................................
Automatic Backlight Off.............................................................................................
Low Battery Indication...............................................................................................
Rotary Switch.................................................................................................................
Pushbuttons...................................................................................................................

2-1
2-1
2-2
2-2
2-3
2-3
2-4
2-5

Model 187 & 189
Users Manual
Selecting the Range.......................................................................................................
Understanding the Display .............................................................................................
Primary Display .........................................................................................................
Secondary Display.....................................................................................................
Bar Graph..................................................................................................................
Using the Input Terminals ..............................................................................................
Using Display Hold .........................................................................................................
Using AutoHOLD............................................................................................................
Using MIN MAX..............................................................................................................
Using FAST MN MX .......................................................................................................
Using HOLD with MIN MAX or FAST MN MX............................................................
Using Relative Mode (REL)............................................................................................
3

2-10
2-10
2-10
2-11
2-11
2-17
2-18
2-19
2-19
2-21
2-22
2-22

Making Measurements................................................................................................. 3-1
Introduction ....................................................................................................................
Measuring Voltage .........................................................................................................
Measuring AC Voltage...............................................................................................
dB Measurements in AC Volts Functions ..................................................................
Measuring DC Voltage ..............................................................................................
Both AC and DC Voltage Measurements ..................................................................
Measuring Resistance....................................................................................................
Testing for Continuity .....................................................................................................
Using Conductance for High Resistance Tests ..............................................................
Measuring Capacitance..................................................................................................
Testing Diodes ...............................................................................................................
Measuring Temperature .................................................................................................
Measuring Current .........................................................................................................
Input Alert™ Feature .................................................................................................

3-1
3-1
3-2
3-3
3-4
3-4
3-6
3-8
3-9
3-12
3-13
3-15
3-16
3-17

Contents (continued)
Measuring AC Current ..............................................................................................
Measuring DC Current ..............................................................................................
Measuring Frequency ....................................................................................................
Measuring Duty Cycle....................................................................................................
Measuring Pulse Width..................................................................................................
4

Using Memory & Communications Features ............................................................ 4-1
Introduction....................................................................................................................
Types of Memory ...........................................................................................................
Saved Readings Memory..........................................................................................
Logged Readings Memory........................................................................................
Storing Saved Readings ................................................................................................
Starting Logging ............................................................................................................
Stopping Logging...........................................................................................................
Viewing Memory Data....................................................................................................
Clearing Memory ...........................................................................................................
Using Communications (187 and 189) ..........................................................................

3-18
3-20
3-22
3-23
3-25

4-1
4-1
4-1
4-1
4-2
4-2
4-2
4-3
4-5
4-5

Changing the Default Settings ................................................................................... 5-1
Introduction....................................................................................................................
Selecting Setup Options ................................................................................................
Adjusting the Temperature Offset..................................................................................
Selecting Display Resolution (3 1/2 or 4 1/2 Digits)......................................................
Setting the Power Off Timeout.......................................................................................
Setting the 24-Hour Clock..............................................................................................
Setting the Line (Main) Frequency.................................................................................
Returning to Factory Defaults ........................................................................................
Saving Setup Options ....................................................................................................

iii

5-1
5-1
5-4
5-6
5-6
5-7
5-7
5-8
5-8

Model 187 & 189
Users Manual
6

Maintenance ................................................................................................................. 6-1
Introduction ....................................................................................................................
General Maintenance.....................................................................................................
Testing the Fuses...........................................................................................................
Replacing the Batteries ..................................................................................................
Replacing the Fuses ......................................................................................................
User-Replaceable Parts .................................................................................................
In Case of Difficulty ........................................................................................................

6-1
6-1
6-1
6-3
6-5
6-5
6-5

Specifications............................................................................................................... 7-1
Safety and Compliances ................................................................................................
Physical Specifications...................................................................................................
Feature Summary...........................................................................................................
Basic Specifications .......................................................................................................
Detailed Accuracy Specifications ...................................................................................
Frequency Counter Sensitivity .......................................................................................
Burden Voltage (A, mA, µA) ...........................................................................................
Input Characteristics.......................................................................................................

7-1
7-2
7-3
7-4
7-5
7-11
7-11
7-12

List of Tables
Table
1-1.
1-2.
2-1.
2-2.
2-3.
3-1.
4-1.
5-1.
5-2.
6-1.

Title
Safety Information.................................................................................................................
International Electrical Symbols............................................................................................
Rotary Switch Selections ......................................................................................................
Pushbuttons..........................................................................................................................
Display Features ...................................................................................................................
Current Measurement ...........................................................................................................
View Display .........................................................................................................................
Function Specific Setup Selections.......................................................................................
Common Setup Selections ...................................................................................................
User-Replaceable Parts........................................................................................................

Page
1-2
1-4
2-6
2-8
2-13
3-16
4-4
5-2
5-3
6-6

Model 187 & 189
Users Manual

List of Figures

Figure

Title

2-1.
2-2.
2-3.
2-4.
2-5.
2-6.
2-7.
2-8.
3-1.
3-2.
3-3.
3-4.
3-5.
3-6.
3-7.
3-8.
3-9.

AC Volts Display ...................................................................................................................
Rotary Switch........................................................................................................................
Pushbuttons..........................................................................................................................
Display Features ...................................................................................................................
Input Terminals .....................................................................................................................
Display Hold and AutoHOLD ................................................................................................
Min Max Avg .........................................................................................................................
Relative Mode.......................................................................................................................
AC Voltage Measurement.....................................................................................................
dBm Display..........................................................................................................................
AC and DC Display ...............................................................................................................
DC Voltage Measurement.....................................................................................................
Resistance Measurement .....................................................................................................
Continuity Test......................................................................................................................
Conductance Measurement..................................................................................................
Capacitance Measurement ...................................................................................................
Diode Test ............................................................................................................................

vii

Page
2-2
2-4
2-5
2-12
2-17
2-18
2-21
2-22
3-2
3-3
3-5
3-6
3-7
3-10
3-11
3-13
3-14

Model 187 & 189
Users Manual
3-10.
3-11.
3-12.
3-13.
3-14.
3-15.
3-16.
3-17.
3-18.
4-1.
5-1.
6-1.
6-2.

Temperature Measurement ...................................................................................................
AC Current Measurement......................................................................................................
DC Current Measurement .....................................................................................................
Functions Allowing Frequency Measurement........................................................................
Hz Display .............................................................................................................................
Duty Cycle Measurements ....................................................................................................
Duty Cycle Display ................................................................................................................
Pulse Width Measurements...................................................................................................
Pulse Width Display ..............................................................................................................
View Display..........................................................................................................................
Adjusting Temperature Offset ...............................................................................................
Testing the Current Fuses.....................................................................................................
Battery and Fuse Replacement .............................................................................................

viii

3-15
3-19
3-21
3-22
3-23
3-24
3-25
3-26
3-27
4-4
5-5
6-2
6-4

Chapter 1

Before You Start
Safety Information

Contacting Fluke

The Fluke Model 187 and Model 189 True RMS
Multimeters (hereafter referred to as the “meter”) comply
with:

To order accessories, receive assistance, or locate the
nearest Fluke distributor or Service Center, call:

•
•
•
•
•
•

EN61010.1:1993
ANSI/ISA S82.01-1994
CAN/CSA C22.2 No. 1010.1-92
1000V Overvoltage Category III, Pollution Degree 2
600V Overvoltage Category IV, Pollution Degree 2
UL 3111-1

Use the meter only as specified in this manual. Otherwise,
the protection provided by the meter may be impaired.
Refer to safety information in Table 1-1.
A Warning identifies conditions and actions that pose
hazards to the user. A Caution identifies conditions and
actions that may damage the meter or the equipment
under test.

USA: 1-888-99-FLUKE (1-888-993-5853)
Canada: 1-800-36-FLUKE (1-800-363-5853)
Europe: +31 402-678-200
Japan: +81-3-3434-0181
Singapore: +65-738-5655
Anywhere in the world: +1-425-446-5500
Address correspondence to:
Fluke Corporation
P.O. Box 9090,
Everett, WA 98206-9090
USA

Fluke Europe B.V.
P.O. Box 1186,
5602 BD Eindhoven
The Netherlands

Visit us on the World Wide Web at: www.fluke.com

1-1

Model 187 & 189
Users Manual
Table 1-1. Safety Information

WWarning
To avoid possible electric shock or personal injury, follow these guidelines:

1-2

•

Do not use the meter if it is damaged. Before you use the meter, inspect the case. Look for cracks or
missing plastic. Pay particular attention to the insulation surrounding the connectors.

•

Inspect the test leads for damaged insulation or exposed metal. Check the test leads for continuity.
Replace damaged test leads before you use the meter.

•

If this product is used in a manner not specified by the manufacturer, the protection provided by the
equipment may be impaired.

•

Do not use the meter if it operates abnormally. Protection may be impaired. When in doubt, have the
meter serviced.

•

Do not operate the meter around explosive gas, vapor, or dust.

•

Do not apply more than the rated voltage, as marked on the meter, between terminals or between any
terminal and earth ground.

•

Before use, verify the meter’s operation by measuring a known voltage.

•

When measuring current, turn off circuit power before connecting the meter in the circuit. Remember
to place the meter in series with the circuit.

•

When servicing the meter, use only specified replacement parts.

•

Use caution when working above 30 V ac rms, 42 V peak, or 60 V dc. Such voltages pose a shock
hazard.

•

Avoid working alone.

Before You Start
Safety Information

Table 1-1. Safety Information (cont.)

WWarning
•
•
•
•
•
•
•

When using the probes, keep your fingers behind the finger guards on the probes.
Connect the common test lead before you connect the live test lead. When you disconnect test leads,
disconnect the live test lead first.
Remove test leads from the meter before you open the battery door.
Do not operate the meter with the battery door or portions of the cover removed or loosened.
To avoid false readings, which could lead to possible electric shock or personal injury, replace the
batteries as soon as the low battery indicator (M) appears.
Use only type AA batteries, properly installed in the meter case, to power the meter.
To avoid the potential for fire or electrical shock, do not connect the thermocouples to electrically live
circuits.

Caution
To avoid possible damage to the meter or to the equipment under test, follow these guidelines:
•
Disconnect circuit power and discharge all high-voltage capacitors before testing resistance,
continuity, diodes, or capacitance.
•
Use the proper terminals, function, and range for your measurements.
•
Before measuring current, check the meter’s fuses and turn power OFF to the circuit before
connecting the meter to the circuit.

1-3

Model 187 & 189
Users Manual

Symbols
Symbols used on the meter and in this manual are
explained in Table 1-2.
Table 1-2. International Electrical Symbols

1-4

AC (Alternating Current)

Earth ground

DC (Direct Current)

Fuse

AC and DC

Double insulated

Battery

Important information

Complies with relevant Canadian
Standards Association directives

Complies with European Union directives

Inspected and licensed by TÜV Product
Services.

Underwriters Laboratories, Inc.

Chapter 2

Getting Acquainted

Introduction

Turning the Meter On

Although this manual describes the operation of both
Models 187 and 189, all illustrations and examples
assume use of Model 189. Additional capabilities with
Model 189 are discussed in Chapter 4. These capabilities
include the following:

To turn the meter on, turn the rotary switch from OFF to
any switch setting.

•

An enhanced memory function that features an
additional position (VIEW MEM) on the rotary switch.

•

Logging

•

Save

•

Memory

The ac volts function (shown in Figure 2-1) is assumed in
the following discussion. You do not need connections to
the input terminals at this time.
If you want a view of the full display (all segments
illuminated), press and hold Q while turning the meter
on. Release the button when you are done viewing the full
display.

2-1

Model 187 & 189
Users Manual

Automatic Power Off

tc031f.eps

The display blanks and the meter goes into a “sleep”
mode if you have not changed the rotary switch position or
pressed a button for a set period. While in Sleep mode,
pressing any button turns the meter on. The meter then
returns to the display for the function selected with the
rotary switch; all previously activated button features
(HOLD, Hz, etc.) are discarded.

Figure 2-1. AC Volts Display

Battery Considerations
The meter uses four AA alkaline batteries. The following
paragraphs describe several techniques used to conserve
battery power.

2-2

The automatic power off is preset to 15 minutes. From the
Setup menu (see Chapter 5), you can specify a maximum
period of 23 hours, 59 minutes. If you set the period to 0,
the meter remains on until you turn the rotary switch to
OFF or the batteries become too weak.
Automatic power off does not occur if the meter is in MIN
MAX, FAST MN MX, AutoHOLD, or LOGGING
(Model 189) mode.

Getting Acquainted
Battery Considerations

Automatic Backlight Off

Low Battery Indication

Press T to select the backlight level (low, high, or off.) In
low or high, the backlight turns off automatically after a
given period. This period is also preset to 15 minutes and
can be set to a maximum of 99 minutes from the setup
menu. If the period is set to 0, the backlight is on
indefinitely and can only be turned off by pressing T or
turning the meter off.

A constant battery icon ( B) in the upper left corner of
the display notifies you that the batteries are low and
should be replaced.

Note
See Chapter 5 for power off and backlight off
setup information.

WWarning
To avoid false readings, which could lead to
possible electric shock or personal injury,
replace the batteries as soon as the battery
icon ( B) appears.
A flashing battery icon means that battery failure is
imminent. The backlight cannot be used in this condition.
MIN MAX and FAST MN MX features turn off. For Model
189, logging and communications also cease.

2-3

Model 187 & 189
Users Manual

Rotary Switch

The rotary switch is shown in Figure 2-2. Each position is
described in Table 2-1.

Turn the meter on by selecting any measurement function
(identified with white letters around the rotary switch). The
meter presents a standard display for that function (range,
measurement units, modifiers, etc.) The display may also
be influenced by some of the choices made in Setup.
Use the blue button to select any rotary switch alternate
function (labeled in blue letters). You can also use other
buttons to choose modifiers for the selected function.
When you turn the rotary switch from one function to
another, a display for the new function appears. Button
choices made in one function do not carry over into
another function.
With Model 189, a VIEW MEM switch position is available;
refer to Chapter 4 for more information.

ac+dc

F
C

ac+dc

A
mA

mV
dB

A
mA

ac+dc

OFF

ac+dc

VIEW MEM
CLEAR MEM
tc012f.eps

Figure 2-2. Rotary Switch

2-4

Getting Acquainted
Pushbuttons

Pushbuttons
The buttons activate features that augment the function
selected with the rotary switch. The buttons are shown in
Figure 2-3 and described in Table 2-2.
Use the blue button ( %) to access functions labeled in
blue for some of the rotary switch positions. Table 2-1
defines all blue button functions.
Use the yellow button ( O) followed by other buttons
to access additional features. These features appear in
yellow above the appropriate keys. Table 2-2 defines
yellow button features. This manual identifies the yellow
button feature in parentheses following the button
sequence . For example, activating the FAST MN MX
mode appears as O M (FAST MN MX).

AutoHOLD

FAST MN MX

HOLD

MIN MAX

LOGGING

YES

REL

CANCEL

SAVE

Hz % ms

RANGE

SETUP

tc013f.eps

Figure 2-3. Pushbuttons
The following yellow button features are not available on
Model 187: (YES), (NO), (LOGGING), and (SAVE).

2-5

Model 187 & 189
Users Manual
Table 2-1. Rotary Switch Selections
Position

% Blue Key Function

Rotary Switch Function

AC voltage measurement from 0 V to 1000.0 V

dB over AC, AC over dB

AC millivolt measurement from 0 mV to 3000.0 mV

dB over AC, AC over dB

DC voltage measurement from 0 V to 1000.0 V

AC over DC (AC in primary display, DC in secondary
display), DC over AC, ac+dc

DC millivolt measurement from 0 mV to 3000.0 mV

AC over DC (AC in primary display, DC in secondary
display), DC over AC, ac+dc

Resistance measurement from 0 Ω to 500.0 MΩ

Continuity test

Conductance measurement from 0 nS to 50.00 nS

Capacitance measurement from 0.001 nF to 50 mF

Diode test

Temperature measurement

Toggles between °C and °F.

2-6

Getting Acquainted
Pushbuttons

Table 2-1. Rotary Switch Positions (cont.)
% Blue Key Function

Position

Rotary Switch Function

AC current measurements from 0 mA to 20.000 A

none

AC current measurements from 0 µA to 5000.0 µA

none

DC current measurements from 0 mA to 20.000 A

AC over DC (AC in primary display, DC in secondary
display), DC over AC, ac+dc

DC current measurements from 0 µA to 5000.0 µA

AC over DC (AC in primary display, DC in secondary
display), DC over AC, ac+dc

(Model 189 only.) Access data held in the meter’s
memory. See Chapter 4 for more information.

CLEAR MEM. See Chapter 4 for more information.

=
K
x
VIEW
MEM

2-7

Model 187 & 189
Users Manual
Table 2-2. Pushbuttons

Button

Yellow Button
Function

Description

Note
Press O to access “Yellow Button Functions.” The O box and the 24-hour clock appear in the lower corners
of the display and the primary display freezes, allowing time to press a second button.
T
l

Press to turn backlight on or off. Also, in Setup, use
the arrow function (l) to select the previous digit or
item in a list.

Press to freeze the displayed value. Press again to
release the display.

2-8

Press to start retaining min, max, and average values.
Press successively to display max, min, and average
values. Press O N (CANCEL) to stop.
Press to store the present reading as an offset
reference; subsequent readings show only the relative
difference from this value. Press again to show the
difference as a percentage of the reference.

SETUP

AutoHOLD

O Q
FAST MN MX

O M

LOGGING

O D

Press to access Setup selections.
Press to store a Setup selection and
proceed to the next selection.
Press to begin AutoHOLD; the last
stable reading is displayed.
Press to start FAST MN MX mode,
where min and max values for short
duration events are stored.
Press to start and stop Logging
(Model 189). Press O + N
(CANCEL) to stop.

Getting Acquainted
Pushbuttons

Table 2-2. Pushbuttons (cont.)

Button
[

]

N
%
s

Description
•
•
•
•
•
•
•
•

In Setup, increment a digit .
In counter functions, select positive pulse slope.
In ohms continuity, select beep on open.
In VIEW MEM, see Chapter 4 (Model 189).
In Setup, decrement a digit .
In counter functions, select negative pulse slope.
In ohms continuity, select beep on short.
In VIEW MEM, see Chapter 4 (Model 189).

Exit AUTO and enter MANUAL ranging. In MANUAL,
select next input range. Press O N
(CANCEL) to return to AUTO.
Successively press for frequency, duty cycle, and
pulse width.
The blue button. Press to access blue functions on
the rotary switch. In Setup, use arrow function ( s) to
select the next digit or item in a list.

Yellow Button
Function

Description

(none)

SAVE

O R

CANCEL

O N

Press to save present reading
(Model 189)
CANCEL any % (blue key) function
and all other button features.

(none)

2-9

Model 187 & 189
Users Manual

Selecting the Range

Understanding the Display

Press R to select either a fixed range or the
autorange feature.

Display features are shown in Figure 2-4 and described in
Table 2-3. Major display features are described in the
following paragraphs.

Note
Note

You cannot use R in conductance, diode
test, and temperature functions or with the REL,
MIN MAX, and FAST MN MX features. These
selections all use a specific fixed range.
Autoranging (AUTO lighted in the display) always comes
on initially when you select a new function. In autorange,
the meter selects the lowest input range possible,
ensuring that the reading appears with the highest
available precision (resolution).
If AUTO is already on, press R to enter MANUAL
ranging in the present range. You can then select the next
manual range each time you press R. Return to
autoranging by pressing O N (CANCEL).

2-10

You can show all display segments (as shown in
Figure 2-4) by pressing Q while turning the
meter on. Release Q to turn off the full
display.

Primary Display
The primary display usually shows the present reading for
the rotary switch function. For most of these functions, the
primary display can be set to show 4 or 5 digits. See
Chapter 5 for more information about display digits.
Other uses for this display are:
•

AutoHOLD: most recent held reading.

•

MIN MAX: maximum, minimum, or average value.

Getting Acquainted
Understanding the Display

•

dB (in ac volts functions): the dBm or dBV value.

Bar Graph

•

REL: the difference between the present reading and
a stored reference reading.

•

Setup: various messages (see Chapter 5).

•

Overload conditions: OL displayed.

•

Error conditions.

The bar graph provides an analog indication of the
measured input. For most measurement functions, the bar
graph updates 40 times per second. Since this response
is much faster than the digital display, the bar graph is
useful for making peak and null adjustments and for
observing rapidly changing inputs. The bar graph is not
available in temperature, capacitance, ac over dc, dc over
ac, and ac+dc functions.

Secondary Display
The secondary display often shows the present reading
when the primary display shows some other feature (MIN
MAX, REL ∆, etc.)
When multiple features are active, the secondary display
shows one of the values. For example, Hz could appear in
the secondary display while dB appears in the primary
display.

2-11

Model 187 & 189
Users Manual

10
9

12
11

6
5

13
4

3
2
14

tc011f.eps

Figure 2-4. Display Features

2-12

Getting Acquainted
Understanding the Display

Table 2-3. Display Features
Number

Feature

Description

Continuity test function is selected.

Bar Graph.
In normal operation 0 (zero) is on the left. In Relative %, 0 is in the center, negative
values are to the left and positive to the right.
The polarity indicator left of the bar graph shows the polarity of the input. Both polarity
indicators appear in REL% mode.
The arrow right of the bar graph indicates an overload condition.
Both arrows appear (without bar graph) when you can use T (l) and % (s) to select
settings in the setup mode.

Percent difference in Relative mode is being displayed in the primary display. The
reference value is shown in the secondary display

Relative (REL ∆) mode is active. The primary display has been modified by the
reference value shown in the secondary display.

Indicates negative readings. In Relative mode, this sign indicates that the present input
is less than the stored reference.
>30 V ac and/or dc may be present at the input terminals.
Low battery. If flashing, battery failure is imminent, and logging and backlight are
disabled.

WWarning

To avoid false readings, which could lead to possible electric shock or personal
injury, replace the battery as soon as the low battery indicator appears.

2-13

Model 187 & 189
Users Manual
Table 2-3. Display Features (cont.)
Number

Feature

Description

FAST
MIN
MAX
AVG

FAST MN MX mode is enabled. ( O M)

;

Readings are being recorded in memory (Model 189 only.) ( O + D)

The meter is in Hold mode. ( Q)

AutoHOLD is active. ( O + Q)

8.8.8.8.8
0L

2-14

Minimum reading displayed.
Maximum reading displayed.
Average reading displayed.

Primary Display (4-1/2 digit)
Overload input.
Measurement Units

V, mV

V: Volts. The unit of voltage.
mV: Millivolt. 1 x 10-3 or 0.001 volts.

dBm, dBV

For ac volts functions, reading is shown in decibels of power above or below 1 mW
(dBm) or decibels of voltage above or below 1 V (dBV).

Getting Acquainted
Understanding the Display

Table 2-3. Display Features (cont.)
Number

Feature

Description

AC+DC

For dc volts and dc amps functions, reading represents the rms total of ac and dc
measurements.

e, ke Me,

Ω: Ohm. The unit of resistance.
kΩ: Kilohm. 1 x 103 or 1000 ohms.
MΩ: Megohm. 1 x 106 or 1,000,000 ohms.

S: Siemens. The unit of conductance.
nS: Nanosiemens. 1 x 10-9 or 0.000000001 Siemens.

nF, µF, mF

°C ,°F
A, mA, µA

Hz, kHz, MHz

F: Farad. The unit of capacitance.
nF: Nanofarad. 1 x 10-9 or 0.000000001 farads.
µF: Microfarad. 1 x 10-6 or 0.000001 farads.
mF: Millifarad. 1 X 10 -3or 0.001 farads.
Degrees Celsius (default) or Fahrenheit.
A: Amperes (amps). The unit of current.
mA: Milliamp. 1 x 10-3 or 0.001 amperes.
µA: Microamp. 1 x 10-6 or 0.000001 amperes.
Hz: Hertz. The unit of frequency.
kHz: Kilohertz. 1 x 103 or 1000 hertz.
MHz: Megahertz. 1 x 106 or 1,000,000 hertz.

2-15

Model 187 & 189
Users Manual
Table 2-3. Display Features (cont.)
Number

Feature
51000
AUTO

Description

MANUAL

Time Display. Used with HOLD, AutoHOLD, MIN MAX, FAST MN MX (SAVE, and
LOGGING Model 189).

fMS88:88

Elapsed Time Display (f on): shown in minutes:seconds to maximum of 59:59 - used if
time since Min, Max, or Logging started is less than 60 minutes. Always used for Min,
Max, Avg. Displays hours:minutes after 1 hour.

88:88

24-hour Display (f off): shown in hours:minutes to maximum of 23:59. For setting the
24-hour clock, refer to Chapter 5.

8.8.8.8

Secondary Display
MEM

q1888

Range. Digits display range in use.

Memory Index Display (Model 189). Also used for dBm reference resistance.

q appears when you can use [ and ]
settings.

2-16

to increment or decrement

Getting Acquainted
Using the Input Terminals

Using the Input Terminals

All functions except current use the
and
COM inputs. Current functions use the inputs shown
below:
•

•

I or K function: Use A and COM inputs from 400

mA
A

COM

mA to 20 A. Use mA/µA and COM for inputs ≤ 400
mA.

= or x function: Use mA/µA and COM for inputs ≤
5000.0 µA.

If a test lead is plugged into the mA/µA or A terminal, but
the rotary switch is not correctly set to one of the current
measuring positions, the Input Alert™ beeper warns you
by making a chirping sound and the primary display shows
"LEAd5". This warning is intended to stop you from
attempting to measure voltage, continuity, resistance,
capacitance, or diode values when the leads are plugged
into a current terminal.

tc014f.eps

Figure 2-5. Input Terminals

Figure 2-5 shows the input terminals.

2-17

Model 187 & 189
Users Manual

Using Display Hold

AutoHOLD

Press Q to enter the Display Hold mode and freeze
the present reading and its time stamp. New readings now
appear in the secondary display. See Figure 2-6. To exit
Display Hold mode, press Q again.
Note
The bar graph and secondary display may show
different units in Capacitance and Ohms due to
Autoranging.
In the MIN MAX mode, Display Hold functions like a
toggle, interrupting and resuming the MIN MAX
operations.
With Model 189, you cannot use Display Hold while
logging data. Model 189 allows you to save the frozen
reading to memory by pressing O R (SAVE).

2-18

tc040f.eps

Figure 2-6. Display Hold and AutoHOLD

Getting Acquainted
Using AutoHOLD

Using AutoHOLD
WWarning
AutoHOLD mode does not capture unstable
or noisy readings. Do not use AutoHOLD
mode to determine that circuits are without
power.
To enter AutoHOLD, press OQ(AutoHOLD).
AutoHOLD mode freezes the present reading and its time
stamp. New readings now appear in the secondary
display. See Figure 2-6. When the meter detects a new,
stable reading (>4% change from last stable reading), it
beeps and displays the new reading in the primary
display. You can also force a primary display update by
pressing Q.
If you remove the test leads (open the input), the meter
retains the last frozen primary display.
You cannot use AutoHOLD when MIN MAX is active. With
Model 189, you cannot initiate AutoHOLD while logging
data, but you can initiate logging when AutoHOLD is
active.

Using MIN MAX
The MIN MAX mode stores minimum (MIN) and maximum
(MAX) input values. When the input goes below the stored
minimum value or above the stored maximum value, the
meter beeps and stores the new value. MIN MAX mode
also calculates an average (AVG) of all readings taken
since the mode was activated.
Press M to enter the MIN MAX mode. The maximum
(MAX) reading is displayed first.
Each subsequent press of M steps through the
minimum (MIN), average (AVG), and back to the
maximum reading.
In the MIN MAX mode, the secondary display continues to
show the present measurement value.
The time elapsed since the MIN MAX mode was entered
is shown in the bottom right corner of each type of display.
See Figure 2-7.

To exit AutoHOLD mode, press O Q (AutoHOLD)
again.

2-19

Model 187 & 189
Users Manual
To exit MIN MAX mode, press O N (CANCEL) or
turn the rotary switch to a different position. Also, MIN
MAX mode turns off automatically when a flashing B
(low battery condition) occurs.
Note
Minimum, maximum, and average values stored
in the MIN MAX mode are lost when the meter is
turned off.
The MIN MAX mode can be used to capture intermittent
readings, store maximum readings while you are away, or
store readings while you are operating the equipment
under test and cannot watch the meter. The average
reading is useful for smoothing out unstable inputs,
calculating power consumption, or estimating the percent
of time a circuit is active.
The MIN MAX mode is appropriate for storing signal
events that last 50 ms or longer in most measurement
functions. Signal events must be 500 ms or longer in the
following functions: continuity, conductance, capacitance,
temperature, Hz, duty cycle, and pulse width.

2-20

Getting Acquainted
Using FAST MN MX

Using FAST MN MX
FAST MN MX can capture transient signal events as short
as 250 µs, but with decreased accuracy; only 3-1/2 display
digits are allowed.
Activate FAST MN MX by pressing O M. As with
regular MIN MAX, you can then press M to cycle
through maximum, minimum, and average primary
displays. The meter beeps for any new minimum or
maximum value. Exit FAST MN MX by pressing
ON (CANCEL) or by turning the rotary switch.
A low battery condition (flashing B) disables FAST MN
MX.
In ac measurement functions, MAX and MIN values are
peak values, AVG is the rms value. This provides the
necessary information in one display for calculation of
Crest Factor (peak/rms).
Due to longer required response times, you cannot use
FAST MN MX in the following functions: ohms, diode test,
conductance, continuity, capacitance, temperature, ac
over dc, ac+dc, Hz, duty cycle, and pulse width.
tc033f.eps

Figure 2-7. Min Max Avg

2-21

Model 187 & 189
Users Manual

Using HOLD with MIN MAX or FAST MN MX

•

You can enable the HOLD mode when in the MIN MAX
mode is by pressing Q.
No further minimum, maximum, or average updates occur
while the HOLD mode is enabled.

Press D a second time to enter the REL% mode
and display the difference as ± 10 % of the reference
reading.
In REL%, e% appears on the display.

•

Press D a third time to exit the Relative Mode.

Exit HOLD mode by pressing Q a second time.

Using Relative Mode (REL)
Selecting Relative mode (D) causes the meter to zero
the display and store the present reading as a reference
for subsequent measurements.
•

Press D once to select the Relative Mode. (The
meter enters manual range when you enter the
Relative Mode.)
The reference appears in the secondary display. The
difference between the reference and a new
measurement appears in the primary display. See
Figure 2-8.

2-22

tc039f.eps

Figure 2-8. Relative Mode

Chapter 3

Making Measurements
Introduction

Ranges available in volts functions are:

Chapter 3 explains how to make measurements. Most
measurement functions can be selected by using the
rotary switch.

•

White letters or symbols identify primary functions; blue
letters or symbols identify alternative functions. Press the
blue button to access these alternate functions.
Frequency-related functions can be selected (Hz, duty
cycle, and pulse width) when the rotary switch is in any
volts or amps position.

Measuring Voltage
Voltage is the difference in electrical potential between
two points. The polarity of ac (alternating current) voltage
varies over time, while the polarity of dc (direct current)
voltage is constant over time.

5.0000 V, 50.000 V, 500.00 V, 1000.0 V
•

50.000 mV, 500.00 mV, and 5000.0 mV
Readings in the 5000.0 mV range overload (0L) near
3000 mV ac or dc. The 5000.0 mV range overlaps the
5.0000 V range to provide direct reading display for
Fluke accessories that have a millivolt output with limits
scaled by 1000. For example, the Fluke 80i-1000
Current Clamp provides 1 mV ac per amp measured up
to 1000 amps.

3-1

Model 187 & 189
Users Manual
When measuring voltage, the meter acts like a 10 MΩ
(10,000,000 Ω) impedance in parallel with the circuit. This
loading effect can cause measurement errors in highimpedance circuits. In most cases, the error is negligible
(0.1% or less) if the circuit impedance is 10 kΩ (10,000 Ω)
or less.

189

LOGGING MULTIMETER

Measuring AC Voltage
The meter presents ac voltage values as rms (root mean
square) readings. The rms value is the equivalent dc
voltage that would produce the same amount of heat in a
resistance as the measured voltage. Your meter features
true rms readings, which are accurate for sinewaves and
other wave forms (with no dc offset) such as square
waves, triangle waves, and staircase waves. For ac with
.
dc offset, use

AutoHOLD

FAST MN MX

HOLD

MIN MAX

Hz % ms

RANGE

ac+dc

YES

REL
SAVE

SETUP

LOGGING

CANCEL

A
mA

ac+dc

OFF

ac+dc

VIEW
CLEAR MEM

Switch
Box

TEMPERATURE

Set up the meter to measure ac volts as shown in
Figure 3-1.

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

All pushbutton features are available in this function. The
blue button ( %) accesses decibel dBm or dBV)
measurements, discussed next in this chapter.

ach001f.eps

Figure 3-1. AC Voltage Measurement

3-2

Making Measurements
Measuring Voltage

dB Measurements in AC Volts Functions
The two ac volts functions allow you to display readings as
deviations in dB (decibels) above or below an established
level.
Set up dB measurements with the following procedure:
1.

Make an ac volts measurement to be used as a
reference point.

Press % to select dB. The dBm (or dBV) value
appears in the primary display and the ac volts
reading appears in the secondary display. A typical
dB display appears in Figure 3-2.

Press % again to switch the ac volts and dB
readings. Press % a third time to turn dB off.

tc032f.eps

Figure 3-2. dBm Display
Normally, dB is measured as dBm, which is a measure of
decibels relative to 1 milliwatt. The meter assumes a
resistance of 600 Ω in making this calculation. This
resistance can be set for any value from 1 to 1999 Ω,
using the meter’s setup capabilities (see Chapter 5.)
When set to other than 600 Ω the dBm reference
resistance appears in the Index Display. (See Figure 2-4,
item 17.)
Note
If dBm is displayed, check that the reference
resistance value closely matches the impedance
of the system being measured.

3-3

Model 187 & 189
Users Manual
dB is calculated with the following formula:

Vx 
dB = 20 * log10  
Vr 
•

•

For dBm, Vr is the voltage across the reference
resistance at 1 mW. For example, Vr would be
0.7746 V with a 600 Ω reference resistance.
For dBV, the reference voltage (Vr) is 1 V.

Measuring DC Voltage
Set up the meter for dc voltage measurement as shown in
Figure 3-4. All pushbutton features are available for a
standard dc volts reading.

Both AC and DC Voltage Measurements
When a dc volts function is selected, the meter can
display ac and dc components of a signal separately or
the combined ac + dc (rms) value.
To select separate ac and dc signal components:
• Press % once to display ac voltage in the primary
display and dc voltage in the secondary display (ac
over dc).
• Press % a second time to reverse the displays (dc
over ac).
• Press % a third time to display the ac + dc rms value
in the primary display. (FAST MN MX is unavailable in
this state.)
• Press % a fourth time to return to the normal dc volts
display.
Figure 3-3 shows some typical displays.

3-4

Making Measurements
Measuring Voltage

AC over DC

DC over AC

AC + DC

tc024f.eps

Figure 3-3. AC and DC Display
When the meter shows ac over dc or dc over ac, the
following other pushbutton functions are not available:
•

AutoHOLD ( O Q)

•

MIN MAX ( M)

•

FAST MN MX ( O M)

•

Hz ( N)

•

Relative ( D)

•

LOGGING (O D)

3-5

Model 187 & 189
Users Manual

Measuring Resistance
189

AutoHOLD

FAST MN MX

LOGGING

HOLD

MIN MAX

REL

CANCEL

SAVE

Hz % ms

RANGE

SETUP

ac+dc

To avoid possible damage to the meter or to
the equipment under test, disconnect circuit
power and discharge all high-voltage
capacitors before measuring resistance.

YES

Resistance is an opposition to current flow. The unit of
resistance is the ohm (Ω). The meter measures resistance
by sending a small current through the circuit.

ac+dc

A
mA

dB mV

Caution

LOGGING MULTIMETER

The meter’s resistance ranges are 500.00 Ω, 5.0000 kΩ,
50.000 kΩ, 500.00 kΩ, 5.0000 MΩ, 30.000 MΩ, and
500.0 MΩ.

A
mA

ac+dc

OFF

ac+dc

VIEW
CLEAR MEM

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

To measure resistance, set up the meter as shown in
Figure 3-5.

CAT
1000V

All pushbutton functions are available with resistance
measurements. The blue key cycles to continuity and
conductance measurement, which are described later in
this chapter.

Note

ach002f.eps

Figure 3-4. DC Voltage Measurement

3-6

In the Ohms Mode, a negative sign (-) on the
display indicates the presence of voltage. This
will cause reading errors.

Making Measurements
Measuring Resistance

In-Circuit Resistance Measurements

Isolating a Potentiometer

Circuit Power

OFF
1
189

3 2

LOGGING MULTIMETER

Disconnect
2

1
AutoHOLD

FAST MN MX

HOLD

MIN MAX

YES

CANCEL

SAVE

RANGE

Isolating a Resistor

ac+dc

A
mA

REL

Hz % ms
SETUP

LOGGING

ac+dc

OFF

ac+dc

VIEW
CLEAR MEM

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

Disconnect
ach004f.eps

Figure 3-5. Resistance Measurement

3-7

Model 187 & 189
Users Manual

Keep the following in mind when measuring resistance:
•

•

Because the meter’s test current flows through all
possible paths between the probe tips, the measured
value of a resistor in a circuit is often different from
the resistor’s rated value.
The test leads can add 0.1 Ω to 0.2 Ω of error to
resistance measurements. To test the leads, touch
the probe tips together and read the resistance of the
leads. If necessary, you can press D to
automatically subtract this value.

The resistance function can produce enough voltage to
forward-bias silicon diode or transistor junctions, causing
them to conduct. To avoid this, do not use the 30 MΩ or
500 MΩ ranges for in-circuit resistance measurements.

Testing for Continuity
Caution
To avoid possible damage to the meter or to
the equipment under test, disconnect circuit
power and discharge all high-voltage
capacitors before testing for continuity.
Continuity is the presence of a complete path for current
flow. The continuity test features a beeper that sounds if a
circuit is complete. The beeper allows you to perform
quick continuity tests without having to watch the display.
The continuity function detects intermittent opens and
shorts lasting as little as 1 millisecond (0.001 second).
These brief contacts cause the meter to emit a short beep.
To select continuity, turn the rotary switch to resistance
position, then press the blue button once. The continuity
symbol (~) appears in the display. Continuity uses
manual ranging only; autoranging is not available. Refer to
Figure 3-6 for continuity testing setup instructions.

3-8

Making Measurements
Using Conductance for High Resistance Tests
Continuity testing provides you with both a visual
indication of the state encountered (usually near 0
resistance for a short or OL for an open) and an audible
beep when the input is low.
In continuity, a short means a measured value less than
5% of full scale. You can raise this threshold by manually
selecting a higher range.
You can select whether the beeper comes on for open or
short conditions, as follows:
•

Press [ to enable the beeper for opens.

•

Press ] to enable the beeper for shorts.

The Hz ( N) and FAST MN MX ( O M)
functions are not available when continuity is selected. All
other pushbutton functions are available. The blue key
cycles among resistance, continuity, and conductance.

Using Conductance for High Resistance
Tests
Conductance, the inverse of resistance, is the ability of a
circuit to pass current. High values of conductance
correspond to low values of resistance.
The unit of conductance is the Siemens (S). The meter’s
50 nS range measures conductance in nanosiemens
(1 nS = 0.000000001 Siemens). Because such small
amounts of conductance correspond to extremely high
resistance, the nS range lets you determine the resistance
of components up to 100,000 MΩ, or 100,000,000,000 Ω
(1 nS = 1,000 MΩ).
To measure conductance, set up the meter as shown in
Figure 3-7; then press the blue key until the nS indicator
appears on the display.
With conductance measurements, the following
pushbutton operations cannot be used:
•

Frequency ( N)

•

FAST MN MX ( O M)

•

Manual ranging ( R)

3-9

Model 187 & 189
Users Manual

For in-circuit tests, turn circuit power off.

189

LOGGING MULTIMETER

AutoHOLD

FAST MN MX

HOLD

MIN MAX

YES

CANCEL

SAVE

RANGE

ac+dc

FAST MN MX

HOLD

MIN MAX

A
mA

ac+dc

OFF

ac+dc

VIEW

1
Press to
select “

ac+dc

SAVE

Hz % ms

RANGE

A
mA

OFF

.”

ac+dc

VIEW
CLEAR MEM

TEMPERATURE

10A MAX
FUSED

400mA
FUSED

mA
A

COM

OFF
(open)

ac+dc

TEMPERATURE

mA
A

CLEAR MEM

YES

REL

ac+dc

OFF
(open)

A
mA

LOGGING

CANCEL

SETUP

LOGGING MULTIMETER

AutoHOLD

ac+dc

189

REL

Hz % ms
SETUP

LOGGING

2
Press
for beep
on short

Press
for beep
on open

10A MAX
FUSED

CAT
1000V

ON
(closed)

COM

400mA
FUSED

CAT
1000V

ON
(closed)
ach003f.eps

Figure 3-6. Continuity Test

3-10

Making Measurements
Using Conductance for High Resistance Tests

The following are some tips for measuring conductance:

189

nS
FAST MN MX

LOGGING

HOLD

MIN MAX

REL

ac+dc

CANCEL

SAVE

Hz % ms

RANGE

YES

There is normally a residual conductance reading with
the test leads open. To ensure accurate readings,
press D with the test leads open to subtract the
residual value.

A
mA

•

ac+dc

High-resistance readings are susceptible to electrical
noise. Use averaging to smooth out most noisy
readings; press M until AVG appears in the
display.

LOGGING MULTIMETER

AutoHOLD

SETUP

•

Press twice to
select nS.

ac+dc

OFF

ac+dc

VIEW
CLEAR MEM

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

ach023f.eps

Figure 3-7. Conductance Measurement

3-11

Model 187 & 189
Users Manual

Measuring Capacitance
Caution
To avoid possible damage to the meter or to
the equipment under test, disconnect circuit
power and discharge all high-voltage
capacitors before measuring capacitance.
Use the dc voltage function to confirm that
the capacitor is discharged.
Capacitance is the ability of a component to store an
electrical charge. The unit of capacitance is the farad (F).
Most capacitors are in the nanofarad (nF) to microfarad
(µF) range.
The meter measures capacitance by charging the
capacitor with a known current for a known period of time,
measuring the resulting voltage, then calculating the
capacitance. Capacitors larger than 100 µF take several
seconds to charge. The capacitor charge can be up to
3 V.
The meter’s capacitance ranges are 1 nF, 10 nF, 100 nF,
1 µF, 10 µF, 100 µF, 1 mF, 10 mF, and 50 mF.

3-12

To measure capacitance, set up the meter as shown in
Figure 3-8. The blue key toggles the selection between
capacitance and diode test.
While measuring capacitance, the following pushbutton
functions are not available:
•

Frequency ( N)

•

FAST MN MX ( O M)

The following are some tips for measuring capacitance:
•

To speed up measurements of similar values, press
R to manually select the proper range.

•

To improve the measurement accuracy of small value
capacitors, press D with the test leads open to
subtract the residual capacitance of the meter and
leads.

Making Measurements
Testing Diodes

Testing Diodes
Caution
189

LOGGING MULTIMETER

AutoHOLD

FAST MN MX

HOLD

MIN MAX

YES

REL

CANCEL

SAVE

Hz % ms

RANGE

SETUP

ac+dc

A
mA

Use the diode test to check diodes, transistors, silicon
controlled rectifiers (SCRs), and other semiconductor
devices. The test sends a current through a
semiconductor junction, then measures the junction’s
voltage drop. A typical junction drops 0.5 V to 0.8 V. In
diode test, the beeper is active. It beeps briefly for a
normal junction and is on continuously if a short is
detected.

ac+dc

LOGGING

To avoid possible damage to the meter or to
the equipment under test, disconnect circuit
power and discharge all high-voltage
capacitors before testing diodes.

ac+dc

OFF

ac+dc

VIEW
CLEAR MEM

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

To test a diode out of a circuit, set up the meter as shown
in Figure 3-9.
+
+
+
+
+
+
+
+

In a circuit, a similar diode should still indicate a forwardbias reading of 0.5 V to 0.8 V; however, the reverse-bias
reading can vary depending on the resistance of other
pathways between the probe tips.

+
ach005f.eps

Figure 3-8. Capacitance Measurement

The blue key toggles between diode test and capacitance.
Since diode test uses a fixed range, R cannot be
used.

3-13

Model 187 & 189
Users Manual

Typical
Reading
189

AutoHOLD

FAST MN MX

HOLD

MIN MAX

YES

REL
SAVE

Hz % ms

RANGE

ac+dc

MIN MAX

ac+dc

A
mA
A

A
mA

ac+dc

OFF

Press for
Diode Test

ac+dc

LOGGING

SAVE

Hz % ms

RANGE

A
mA

OFF

ac+dc

VIEW
CLEAR MEM

COM

400mA
FUSED

ac+dc

TEMPERATURE

mA
A

Reverse Bias

VIEW

10A MAX
FUSED

CLEAR MEM

YES

REL

CANCEL

Forward Bias

FAST MN MX

HOLD

SETUP

LOGGING MULTIMETER

AutoHOLD

ac+dc

LOGGING

CANCEL

SETUP

189

LOGGING MULTIMETER

CAT
1000V

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

ach006f.eps

Figure 3-9. Diode Test

3-14

Making Measurements
Measuring Temperature

Measuring Temperature
To measure temperature, set up the meter as shown in
Figure 3-10. The meter begins temperature measurement
in the degree units last used (Celsius °C or Fahrenheit °F).
Once you have selected the temperature function, you can
change units by pressing the blue button. The meter
remembers the units selected until they are changed.
The primary display shows either the temperature or the
message ‘0PEn’ (for an open thermocouple condition).
Shorting the input will display the temperature at the meter
terminals.

189

LOGGING MULTIMETER

AutoHOLD

FAST MN MX

LOGGING

HOLD

MIN MAX

REL

CANCEL

SAVE

Hz % ms

RANGE

SETUP

ac+dc

A
mA

ac+dc

YES

ac+dc

OFF

The secondary display shows any non-zero temperature
offset. This offset is established as a calibrating value
during setup. Refer to Chapter 5 for additional information.

ac+dc

VIEW
CLEAR MEM

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

The following pushbuttons cannot be used when taking
temperature measurements:
•
•
•

Frequency ( N)
FAST MN MX ( O M)
Ranging ( R)

WWarning
To avoid the potential for fire or electrical
shock, do not connect the thermocouples to
electrically live circuits.

80AK
80PK-1 Type K
Thermocouple
Probe

Vent
or
Pipe

ach010f.eps

Figure 3-10. Temperature Measurement

3-15

Model 187 & 189
Users Manual

Measuring Current
WWarning
Never attempt an in-circuit current
measurement where the open-circuit potential
to earth is greater than 1000 V. You may
damage the meter or be injured if the fuse
blows during such a measurement.

To measure ac or dc current, proceed as follows:
1.

Turn off power to the circuit. Discharge all highvoltage capacitors.

Insert the black lead into the COM terminal. Insert the
red lead in an input appropriate for the measurement
range as shown in Table 3-1.
Note

Caution
To avoid possible damage to the meter or to
the equipment under test, check the meter’s
fuses before measuring current. Use the
proper terminals, function, and range for your
measurement. Never place the probes across
(in parallel with) any circuit or component
when the leads are plugged into the current
terminals.

To avoid blowing the meter’s 440 mA fuse, use
the mA/µA terminal only if you are sure the
current is less than 400 mA.
Table 3-1. Current Measurement
Rotary Switch

Input

I or K

Current is the flow of electrons through a conductor. To
measure current, you must open the circuit under test,
then place the meter in series with the circuit.

#
= or x

3-16

Ranges
5.0000 A
10.000 A (reading flashes at
10 A, overloads (0L) at 20 A)
50.000 mA
500.00 mA
500.00 µA
5000.0 µA

Making Measurements
Measuring Current
3.

If you are using the A terminal, set the rotary switch to
mA/A. If you are using the mA/µA terminal, set the
rotary switch to µA for currents below 5000 µA
(5 mA), or mA/A for currents above 5000 µA.
Open the circuit path to be tested. Touch the red
probe to the more positive side of the break; touch
the black probe to the more negative side of the
break. Reversing the leads will produce a negative
reading, but will not damage the meter.

Turn on power to the circuit; then read the display. Be
sure to note the unit given at the right side of the
display (µA, mA, or A).

Turn off power to the circuit and discharge all highvoltage capacitors. Remove the meter and restore the
circuit to normal operation.

Input Alert™ Feature
If a test lead is plugged into the mA/µA or A terminal, but
the rotary switch is not correctly set to one of the current
measuring positions, the beeper warns you by making a
chirping sound and the display shows "LEAd5".
This Input Alert warning is intended to stop you from
attempting to measure voltage, continuity, resistance,
capacitance, or diode values when the leads are plugged
into a current terminal.
Placing the probes across (in parallel with) a powered
circuit when a lead is plugged into a current terminal can
damage the circuit you are testing and blow the meter’s
fuse. This can happen because the resistance through the
meter’s current terminals is very low, so the meter acts like
a short circuit.
Note
The beeper may sound in the presence of high
electical noise, such as that found near Pulse
Width Modulation (PWM) motor drives.

3-17

Model 187 & 189
Users Manual
The following are some tips for measuring current:

Measuring AC Current

•

If the display shows LEAd5 and you are sure the
meter is set up correctly, test the meter’s fuses as
described under "Testing the Fuses" in Chapter 6.

To measure ac current, set up the meter as shown in
Figure 3-11.

•

A current meter drops a small voltage across itself,
which might affect circuit operation. You can calculate
this burden voltage using the values listed in Chapter
7 under Burden Voltage (A, mA, µA).

3-18

The blue pushbutton cannot be used with ac current
measurement. All other pushbutton features can be used.

Making Measurements
Measuring Current

189

AutoHOLD

FAST MN MX

HOLD

MIN MAX

YES

REL
SAVE

Hz % ms

RANGE

ac+dc

A
mA

FAST MN MX

HOLD

MIN MAX

A
mA

YES

REL
SAVE

Hz % ms

RANGE

ac+dc

A
mA

ac+dc

OFF

ac+dc

RANGE

CAT
1000V

A
mA

A
ac+dc

OFF

ac+dc

VIEW
CLEAR MEM

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

A
mA

VIEW

COM

400mA
FUSED

Hz % ms

CLEAR MEM

TEMPERATURE

mA
A

SAVE

ac+dc

VIEW

10A MAX
FUSED

ac+dc

CLEAR MEM

YES

REL

ac+dc

LOGGING

CANCEL

ac+dc

OFF

MIN MAX

A
mA

FAST MN MX

HOLD

SETUP

LOGGING MULTIMETER

AutoHOLD

ac+dc

LOGGING

CANCEL

SETUP

189

LOGGING MULTIMETER

AutoHOLD

ac+dc

LOGGING

CANCEL

SETUP

189

LOGGING MULTIMETER

CAT
1000V

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

ach008f.eps

Figure 3-11. AC Current Measurement

3-19

Model 187 & 189
Users Manual

Measuring DC Current
To measure dc current, set up the meter as shown in
Figure 3-12.
You can view separate dc and ac amps signal
components.
• Press % once to display ac current in the primary
display and dc current in the secondary display
(ac over dc).
• Press % a second time to reverse the displays (dc
over ac).
In either of these states, the following pushbutton
functions are not available:
Display hold ( Q).
AutoHOLD ( O Q)
MIN MAX ( M)
FAST MN MX ( O M)
Hz ( N)
Relative ( D)
LOGGING and SAVE (Model 189)

3-20

• Press % a third time to display the ac + dc rms value
in the primary display. (FAST MN MX is unavailable in
this state.)
• Press % a fourth time to return to the normal dc
display.

Making Measurements
Measuring Current

Circuit Power:
OFF to connect meter.
ON for measurement.
OFF to disconnect meter.

189

FAST MN MX

HOLD

MIN MAX

LOGGING

YES

REL

CANCEL

SAVE

Hz % ms

RANGE

Current through one component

ac+dc

A
mA

Total current to circuit

LOGGING MULTIMETER

AutoHOLD

SETUP

ac+dc

A
mA

ac+dc

OFF

ac+dc

TEMPERATURE

mA
A

A
10A MAX
FUSED

COM

400mA
FUSED

CAT
1000V

ach007f.eps

Figure 3-12. DC Current Measurement

3-21

Model 187 & 189
Users Manual

Measuring Frequency

Frequency is the number of cycles a signal completes
each second. The meter measures the frequency of a
voltage or current signal by counting the number of times
the signal crosses a threshold level each second.
Figure 3-13 highlights the function selections that allow
frequency measurement.
To measure frequency, select an appropriate function,
connect the meter signal source, and press N.
The meter autoranges to one of four frequency ranges:
500.00 Hz, 5.0000 kHz, 50.000 kHz, and 999.99 kHz.
Figure 3-14 shows a typical frequency display.

ac+dc

V
ac+dc

F
C

A
mA

mV
dB

OFF

A
mA

ac+dc

A
ac+dc

VIEW MEM
CLEAR MEM
tc021f.eps

Figure 3-13. Functions Allowing Frequency
Measurement

3-22

Making Measurements
Measuring Duty Cycle

The following are some tips for measuring frequency:

tc026f.eps

Figure 3-14. Hz Display
The meter beeps to indicate when a particular pushbutton
is not allowed when measuring frequency. The following
are some general rules.
•

Relative ( D), Hold ( Q), and MIN MAX
( M)can be used.

•

FAST MN MX ( O M) cannot be used.

•

If a reading shows as 0 Hz or is unstable, the input
signal may be below or near the trigger level. You can
usually correct these problems by selecting a lower
range, which increases the sensitivity of the meter.

•

If a reading seems to be a multiple of what you
expect, the input signal may be distorted. Distortion
can cause multiple triggerings of the frequency
counter. Selecting a higher voltage range might solve
this problem by decreasing the sensitivity of the
meter. In general, the lowest frequency displayed is
the correct one.

Measuring Duty Cycle
Duty cycle (or duty factor) is the percentage of time a
signal is above or below a trigger level during one cycle
(Figure 3-15).
The duty cycle mode is optimized for measuring the on or
off time of logic and switching signals. Systems such as
electronic fuel injection systems and switching power
supplies are controlled by pulses of varying width, which
can be checked by measuring duty cycle.

3-23

Model 187 & 189
Users Manual

Measures Positive Pulse
+Slope
Trigger Point

-Slope
Trigger Point
30% Above
Trigger
Point
100%

Measures Negative Pulse
-Slope
Trigger Point

+Slope
Trigger Point

70% Below
Trigger Point
100%

tc009f.eps

Figure 3-15. Duty Cycle Measurements

3-24

Making Measurements
Measuring Pulse Width

To measure duty cycle, set up the meter to measure
frequency; then press N a second time. You can
select the level the meter uses by pressing [ to
trigger on the positive slope or ] to trigger on the
negative slope. A typical duty cycle display is shown in
Figure 3-16.

input range will often measure better than the AUTOselected input range.
If a duty cycle reading is unstable, press M until the
AVG annunciator comes on and the average reading
appears in the secondary display.

Measuring Pulse Width
The pulse width function allows you to measure the
amount of time a signal is high or low within a given
period. See Figure 3-17. The measured waveform must
be periodic; its pattern must repeat at equal time intervals.

tc027f.eps

Figure 3-16. Duty Cycle Display
For 5 V logic signals, use the 5 V dc range. For 12 V
switching signals in automobiles, use the 50 V dc range.
For sine waves, use the lowest ac or dc range that does
not result in multiple triggering. A manually-selected lower

3-25

Model 187 & 189
Users Manual

Start and Stop on Positive Slope
+Slope
Trigger Point
Pulse
Width
1
Period = Frequency

Start and Stop on Negative Slope
-Slope
Trigger Point

Pulse Width
Period
tc020f.eps

Figure 3-17. Pulse Width Measurements

3-26

Making Measurements
Measuring Pulse Width

The meter measures pulse width in the 500.00 or
1000.0 ms ranges.
To measure pulse width, set up the meter to measure
frequency; then press N two more times. As with the
duty cycle function, you can select which level the meter
uses by pressing [ to trigger on the positive slope or
] to trigger on the negative slope. A typical pulse
width display is shown in Figure 3-18.
You can improve pulse width stability by selecting the
averaging feature. Press M until “AVG” appears in the
display.
tc028f.eps

Figure 3-18. Pulse Width Display

3-27

Model 187 & 189
Users Manual

3-28

Chapter 4

Using Memory & Communications Features
Introduction

Logged Readings Memory

Chapter 4 shows you how to use memory and
communication features available on the meters.

The logging interval (Log Int) can be set using the meter
or FlukeView Forms. You can view the average reading
for each logging interval on the meter’s display. A
scheduled logging interval may contain stable and
unstable logged readings. Unstable logged readings
represent unstable events as defined by the AutoHOLD
function. See the Specifications.

Note
Memory, Logging, and Save features apply to the
189 only.

Types of Memory
The meter has two types of memory data: saved readings
and logged readings.

Saved Readings Memory
Saved readings include primary and secondary readings
and functions, the time stamp, and display icons
representing various features in effect.

To provide more detailed logging information, the meter
also stores the high, low, and average value for each set
of stable and unstable logged readings. You can only
access these logged readings using FlukeView Forms.
Some of the logged readings can only be accessed using
a PC running the FlukeView Forms software. FlukeView
Forms displays the data in graphical or tabular form,
prints, and stores the data.

4-1

Model 187 & 189
Users Manual

Storing Saved Readings

Starting Logging

To add the current displayed reading to the saved
readings memory, press O R (SAVE).

To begin logging, press O D(LOGGING).

•

5AVEd appears briefly to confirm the operation and
the index number display increments by one.

•

FULL appears if no room is available in the saved
readings memory (after 100 saves).

Saved readings can be viewed later as originally
displayed. Actual primary and secondary readings and
functions, the time stamp, and display icons are all stored
in stored readings memory. (The meter does not save the
bar graph.) For example, if the original reading was in
volts ac function with the dB modifier selected, the saved
reading will contain the saved dB value.

; is shown on the display. The logging interval is
preset to 15 minutes.
To change the logging interval, see “Selecting Setup
Options” in Chapter 5. The logging interval can be as high
as 99 minutes or as low as 1 second. There is enough
meter memory for at least 288 intervals (3 days of 15minute intervals.) Use FlukeView Forms to store additional
logging data in your PC's memory.
Note
The meter allows interval logging to begin only if
logged readings memory is empty. Refer to the
“Clearing Memory” discussion below.

Stopping Logging
Logging stops when one of the following occurs:
•
•
•
•

4-2

You press O N (CANCEL).
A flashing low battery condition (B) occurs.
Logged readings memory becomes full.
You change the rotary switch position.

Using Memory & Communications Features
Viewing Memory Data

Viewing Memory Data

The primary display shows memory data. Refer to
Figure 4-1 for an explanation of the VIEW MEM
display.

If the primary display data is a logged reading, ;
appears in the display. You can switch between the
two types of memory data.

Use the following procedure to view memory data:
Note
Viewing memory data involves turning the rotary
switch from its current function. Selections are
not retained when you turn the switch. To return
the meter to this function after viewing memory
data, note the function and the enabled
selections before you turn the rotary switch.
1.

Press R (SAVE) for saved reading.
Press D (LOGGING) for logged reading
To view more detailed logged reading information,
use FlukeView Forms software.

Disconnect the input leads at the measurement
source.
5.
To avoid electric shock, disconnect the test
leads at the measurement source prior to
viewing memory data.

The index (lower left corner of the display) identifies
the displayed memory data by number. You can view
additional memory data by pressing [ and ].

Repeat steps 4 and 5 to switch between the two types
of memory data.

Turn the rotary switch to the VIEW MEM position.

To exit viewing memory, turn the rotary switch to any
other position. Remember that the meter returns to
the default selections for the new function position.

WWarning

4-3

Model 187 & 189
Users Manual
Table 4-1. View Display
No.

tc035f.eps

Figure 4-1. View Display

4-4

Item

Description

q arrow
icons.

Denotes use of [ or ]
to select higher or lower index
numbers.

Z symbol

Hazardous voltage could be
present at inputs.

;

Identifies that the average of a
logging interval is displayed.
When off, a saved reading is
displayed.

Memory
data

Shows logged readings or
secondary readings.

Time
display

Indicates a time stamp (f off) or
elapsed time (f on) display.

MEM

On during View memory.

Index
number

Identifies the data entry being
viewed.

Using Memory & Communications Features
Clearing Memory

Clearing Memory
You can clear memory in two ways.
•

First, If the rotary switch is in the VIEW MEM position,
you can press the blue button (%) to activate the
CLEAR MEM function. CLr.? appears in the display.
You are then prompted to press [ (YES) to clear
the type of memory presently in use or ] (NO) to
stop the clear procedure. The display defines the type
of memory to be cleared, as:
; to clear logged readings memory.
MEM to clear saved readings memory.

•

A second clearing procedure is required when you try
to start logging and the logged readings memory is
not empty.
CLr.? appears in the display. To clear the logged
readings memory and begin logging new data, Press
[ (YES).
To decline the clearing operation and not begin
logging, press ] (NO).

If you attempt to save a meter reading when saved
readings memory is full, FULL appears in the display. You
must use the VIEW MEM function to clear saved readings
memory before proceeding.

Using Communications (187 and 189)
When using a PC-to-meter IR (infrared) communication
link, refer to the FlukeView Forms Installation Guide or the
on-line help.
You can use the IR communication link and FlukeView
Forms software to transfer the contents of a meter’s
memory to a PC.
Note
The 187 and 189 will log in real time mode to a
connected computer running FlukeView Forms.
In addition, the 189 allows the user to log to
internal memory and connect to the computer
later for download.
FlukeView Forms allows you to place the data into
standard (default) or customized forms. The forms can
display the data in table and graph form, as well as view
user comments. You can use these forms to satisfy ISO9000 and other documentation requirements.

4-5

Model 187 & 189
Users Manual

4-6

Chapter 5

Changing the Default Settings
Introduction
The meter allows you to change the default operating
configuration of the meter by changing setup options
made at the factory.
Many of these setup options affect general meter
operations and are active in all functions. Others are
limited to one function or group of functions.
These settings are stored and can be changed in the
Setup mode using the procedure described in this
chapter.

Selecting Setup Options
To enter the Setup mode, turn the meter on and press
O T (SETUP).

In the Setup mode, each press of O T (SETUP)
saves changes to the last selection and steps to the next
option.
Each setup option appears in the primary display in the
sequence shown in Tables 5-1 and 5-2.
The options in Table 5-1 are available only when the
preconditions are met. The options in Table 5-2 are
available for all functions. (When measuring dc volts, none
of the preconditions in Table 5-1 are required, and only
the selections shown in Table 5-2 will appear.)
To exit the Setup mode, Press O N (CANCEL).
Be sure to save your last selection by pressing O T
first.)

5-1

Model 187 & 189
Users Manual
Table 5-1. Function Specific Setup Selections
Selection

Precondition

000.0 °C
or
000.0 °F

Temperature ( w )
selected.

L Int

Model 189 only.

Choices ( < > )

Option
Temperature
offset adjust

Factory Default

000.0 ° to ±100.0 °C(180.0°F) - Use q to
increment or decrement digit.

000.0 °C (or °F)

Use < > to select digit. Selected digit
flashes.
Log interval

MM:SS - Use q to increment or
decrement minute or second values.

15:00

Use < > to select minute or seconds.
Selected values flash.
dbrEF
dbrEF

AC volts (\ or
,) selected.

AC volts (\ or
,) and dBm

selected.

5-2

dB type

dBm or dBV (m or V flashing) - Use <
to select.

dBm reference

0001 Ω to 1999 Ω - Use q to increment
or decrement digit.
Use <

> to select digit.

dBV
0600 Ω

Changing the Default Settings
Selecting Setup Options

Table 5-2. Common Setup Selections
Selection

Option

bEEP

Beeper

8888

Display digits

bLoFF

Backlight time out

Choices
yE5 or no (flashing) Use <

> to select.
8888 (4) or 88888 (5) Use < > to select.
MM:SS - Use q to increment or decrement minute or
second values.

Factory Default
yE5
88888
15:00

Use < > to select minutes or seconds. Selected values
flash. Setting value to 00:00 disables timeout.
Pr0FF

Power off time out

HH:MM - Use q to increment or decrement hour or minute
values.
Use <

Hour

24-hour clock

00:15

> to select hours or minutes. Selected values flash.

HH:MM - Use q to increment or decrement hour or minute
values.
Use <

50-60

Line/Main frequency

Fcty

Restore factory defaults

> to select hours or minutes. Selected values flash.
60 or 50 (flashing) - Use < > to select.
yE5 or no (flashing) - Use < > to select.

00:00

60
no

5-3

Model 187 & 189
Users Manual
Select and edit setup options as follows:

Adjusting the Temperature Offset

•

Turn the rotary switch to a measurement function:

•

Press O T to advance to the next setup option
and save the present selection.

If the meter is in a temperature measurement function,
use the following procedure to set an offset for your
temperature probe:

•

Press [ to increase or ] to decrease a value.

•

Press T (l) to go back to the previous digit or
selection.

•

Press % ( s) to advance to the next digit or
selection.

•

Any digit or selection being changed flashes when
active.

•

Press O N (CANCEL) to exit Setup. (Be sure
to save your last selection by pressing O T first.)

5-4

Turn the rotary switch to temperature (w).

Connect the temperature probe and probe adapter to
and V inputs on the meter.
the

Place the temperature probe and an accurate
thermometer in a lag bath (i.e., a container with an
isothermal liquid).

Press O T to enter the Setup mode and
temperature adjust.

The primary display shows the measured value for the
temperature probe. This value is already adjusted by any
previously stored offset (shown in the secondary display.)
See Figure 5-1.

Changing the Default Settings
Adjusting the Temperature Offset

If necessary, adjust the temperature offset until the
temperature on the primary display matches the
temperature indicated by the lag bath thermometer.
1.

Press % ( s) to advance to the next digit and press
T (l) to go back to the previous digit.

Press [ or ] to increase or decrease the digit
value.

Save changes by pressing O T.

Press O N to exit Setup.

tc041f.eps

Figure 5-1. Adjusting Temperature Offset

5-5

Model 187 & 189
Users Manual

Selecting Display Resolution
(3 1/2 or 4 1/2 Digits)

Setting the Power Off Timeout
1.

For most functions, you can choose whether the meter
displays the reading in 3-1/2 or 4-1/2 digits.
•

The 3-1/2 digit setting provides lower resolution with
faster response time.

•

The 4-1/2 digit setting provides greater resolution with
slower response time. The 4-1/2 digit display is
available with all functions except continuity,
conductance, capacitance, and FAST MN MX.

The present power off time in hours and minutes
appears as four digits in the lower right corner of the
display. The maximum timeout setting is 23 hours and
59 minutes. The minimum setting (00:00) disables the
power off timeout.
2.

Press % (to advance) or T (to go back) between
digits.

With the desired digit selected (flashing), press [
(to increment) or ] (to decrement) the value.

When you have set the digits as desired, press
OT to save the settings and proceed to the next
setup selection.

To select the display resolution:
1.

Press O, then T until 8888 (for 3-1/2 digits) or
88888 (for 4-1/2 digits) appears in the display.

To change the selection, press T (l) or % ( s).

Press O, then T to save the selection and
proceed to the next setup selection.

5-6

Press O T until Pr0FF appears in the display.

Changing the Default Settings
Setting the 24-Hour Clock

Setting the 24-Hour Clock

Press % ( s) to advance to the minute setting; the
minute digits begin flashing.

The meter uses 24-hour clock readings as time stamps
during HOLD, AutoHOLD, MIN MAX, FAST MN MX,
SAVE, and LOGGING operations.

Press [ or ] to increase or decrease the
minute value.

Hours and minutes to a maximum of 23:59 can be set.

Press O T to store the selection and proceed to
the next selection.

Note
The meter uses elapsed time for all MIN MAX
readings. Elapsed time is expressed in minutes
and seconds to a maximum of 59:59 and then
changes to hours and minutes.
To change the 24-hour clock:
1.

Press O T until Hour appears in the display and
the hour digits in the lower right corner of the display
begin flashing.
Press [ or ] to increase or decrease the
hour value.

Setting the Line (Main) Frequency
Although the meter operates on battery power only, it is
important to specify the frequency (50 or 60 Hz) of the line
(main) power. This allows the meter to filter out related
noise.
To change the line (main) frequency:
1.

Press O T until 50-60 appears in the display.

Press T or % to change the selection to the correct
frequency.

Press O T to store the selection and proceed to
the next selection.

5-7

Model 187 & 189
Users Manual

Returning to Factory Defaults

Saving Setup Options

Your meter comes with the setup options preset at the
factory. These factory settings are shown in Tables 5-1
and 5-2. You can always return to these settings as
follows:

At each setup option, store your choice and advance to
the next option by pressing O T.

Press O T until Fcty appears in the display.

Press % to select yE5; press T to select no.
If you select yE5, all setup options revert to the
factory defaults; you cannot specify individual
choices.

Press O T to exit the setup procedure and
activate your selection.
If you selected yE5 in step 2, all factory settings are
restored.
If you selected no, selections made in the Setup
mode become active.

5-8

If you are storing the last option, this also exits the setup
mode.
To exit the Setup mode without saving the present option,
press O N(CANCEL).
Selections that were previously saved with O T are
retained.

Chapter 6

Maintenance
Introduction

This chapter describes basic operator maintenance. For
calibration and performance test information, order the
187 & 189 Service Manual, PN 1584337.

Testing the Fuses

General Maintenance
Periodically wipe the case with a damp cloth and mild
detergent. Do not use abrasives or solvents.
Dirt or moisture in the terminals can affect readings and
can falsely activate the Input Alert feature. Clean the
terminals as follows:
1.

Turn the meter off and remove all test leads.

Shake out any dirt that may be in the terminals.

Soak a new swab with alcohol. Work the swab around
in each terminal.

Before measuring current, test the appropriate fuse as
shown in Figure 6-1. If the tests give readings other than
those shown, have the meter serviced.

WWarning
To avoid electrical shock or personal injury,
remove the test leads and any input signals
before replacing the battery or fuses. To
prevent damage or injury, install ONLY
specified replacement fuses with the
amperage, voltage, and speed ratings shown
in Chapter 7.

6-1

Model 187 & 189
Users Manual

Replace F2 if "
displayed

Replace F1 if "
displayed

189 LO
GGIN
G

MUL
TIMET
ER

FAST
MN

MIN
MAX

HOLD

Hz %
m

ac+d
c
dB

ac+d
c

O FF

VIE

CLEA
W
RM
EM

10A
FUSEMAX
D

mA
A
400m
FUSE
A
D

CO
M

TEMP

ERAT

ac+d
c

C F
A
mA
A
A
mA
ac+d
c

VIE
CLEA
W
RM
EM

A
10A
FUSEMAX
D

URE

V
CA
1000T
V

mA
A
400m
FUSE
A
D

CO
M

YES
SAVE

RAN
GE

O FF

A
mA

LOGG
ING

REL

Hz %
m

SETU
P

SAVE

RAN
GE

CANC
EL

YES

ac+d
c

LOGG
ING

REL

FAST
MN

MIN
MAX

CANC
EL

ac+d
c

MUL
TIMET
ER

AutoH
OLD

HOLD

SETU
P

TEMP

ERAT

ac+d
c

C F
A
mA
A
A
mA
ac+d
c

A
mA

URE

V
CA
1000T
V

ach038f.eps

Figure 6-1. Testing the Current Fuses

6-2

Maintenance
Replacing the Batteries

Replacing the Batteries
Replace the batteries with four AA batteries (NEDA I5A or
IEC LR6).

WWarning
To avoid false readings, which could lead to
possible electric shock or personal injury,
replace the batteries as soon as the battery
indicator (B) appears.

Replace the batteries as follows (refer to Figure 6-2):
1.

Turn the rotary switch to OFF and remove the test
leads from the terminals.

Remove the battery door by using a standard-blade
screwdriver to turn the battery door screws onequarter turn counterclockwise.

Replace the batteries and the battery door. Secure
the door by turning the screws one-quarter turn
clockwise.

6-3

Model 187 & 189
Users Manual

tc037f.eps

Figure 6-2. Battery and Fuse Replacement

6-4

Maintenance
Replacing the Fuses

Replacing the Fuses
W Warning
To avoid electrical shock or damage to the
meter, only use replacement fuses specified
in Table 6-1.
Referring to Figure 6-2, examine or replace the meter’s
fuses as follows:
1.

Turn the rotary switch to OFF and remove the test
leads from the terminals.

Remove the battery acccess door by using a
standard-blade screwdriver to turn the battery door
screws one-quarter turn counterclockwise.

Remove either fuse by gently prying one end loose,
then sliding the fuse out of its bracket.

Install ONLY specified replacement fuses with the
amperage, voltage, and speed ratings shown in
Chapter 7.

Reinstall the battery door. Secure the door by turning
the screws one-quarter turn clockwise.

User-Replaceable Parts
User-replaceable parts are listed in Table 6-1. These parts
can be ordered by contacting Fluke. See “How to Contact
Fluke" in Chapter 1.

In Case of Difficulty
If the meter does not seem to work properly:
1.

Examine the case for damage. If damage is detected,
contact Fluke. See “Contacting Fluke” in Chapter 1.

Check and replace (as needed) the batteries, fuses,
and test leads.

Review this manual to verify correct operation.

If the meter still does not work, pack it securely and
forward it, postage paid, to the location provided by
the appropriate Fluke contact. Include a description of
the problem. Fluke assumes no responsibility for
damage in transit.

A meter under warranty will be repaired or replaced (at
Fluke’s option) and returned at no charge. See the
registration card for warranty terms.

6-5

Model 187 & 189
Users Manual
Table 6-1. User-Replaceable Parts
Description

Reference Designators

Part Number

Qty

Access Door, Battery / Fuse

MP14

666446

Tilt-Stand

MP8

659026

Accessory Mount

MP9

658424

WFuse, 0.44 A (44/100 A, 440 mA), 1000 V, FAST

943121

WFuse, 11 A,1000 V FAST

803293

Battery, 1.5 V, 0-15 mA, AA Alkaline

H8, H9, H10, H11

376756

Fasteners, Battery / Fuse Access Door

H12, H13

948609

Screws, Phillip-Head

H4, H5, H6, H7

832246

AC70A Alligator Clip (Black)

MP38

738047

AC70A Alligator Clip (Red)

MP39

738120

TL71 Right-Angle Test Lead Set

MP34

Getting Started Manual

(TM1-TM5)

CD-ROM (Contains Users Manual)

(TM6)

802980

(see footnote)

1576992

Getting Started Manual PNs: English=1547486; French, German, Italian, Dutch=1555282; Danish, Finnish, Norwegian,
Swedish=1555307; French, Spanish, Portuguese=1555294; Simplified Chinese, Traditional Chinese, Korean, Japanese,Thai=1555282

6-6

Chapter 7

Specifications
Safety and Compliances
Maximum voltage between any terminal and earth
ground.

1000 V dc or rms ac

Compliances - DUAL RATINGS

Complies with IEC 1010-1 to 1000 V Overvoltage Category III,
Pollution Degree 2; and IEC 664-1 to 600 V Overvoltage Category
IV, Pollution Degree 2 *
CSA per standard CSA/CAN C22.2 No. 1010.1-92
UL per standard UL 3111 TÜV per standard EN 61010 Part 1-1993
8 kV peak per IEC 1010.1-92
0.44 A (44/100 A, 440 mA), 1000 V FAST Fuse
11 A, 1000 V FAST Fuse

Certifications (Iisted and pending)

Surge Protection
Fuse Protection for mA or µA inputs
Fuse Protection for A input
Markings

P)
,

,UL, TÜV and #

* OVERVOLTAGE (Installation) Categories refer to the level of Impulse Withstand Voltage protection provided at the specified
Pollution Degree.
•
Overvoltage Category III equipment is equipment in fixed installations. Examples include switch gear and polyphase motors.
•
Overvoltage Category IV equipment is equipment for use at the origin of the installation. Examples include electricity meter
and primary over-current protection equipment.

7-1

Model 187 & 189
Users Manual

Physical Specifications
Display (LCD)

Operating Temperature
Storage Temperature
Temperature Coefficient
Relative Humidity
Altitude

Battery Type
Battery Life
Shock Vibration
Electromagnetic Compatibility
(EMC)
Size
Weight
Warranty
Calibration Interval

7-2

Digital: 50000/5000 counts primary display,
5000 counts secondary display;
updates 4/second.
Analog: 51 segments, updates 40/second.
− 20 °C to + 55 °C
− 40 °C to + 60 °C
0.05 x (specified accuracy) / °C (<18 °C or >28 °C)
0 % to 90 % (0 °C to 35 °C)
0 % to 70 % (35 °C to 55 °C)
Operating: 0-2000 meters per EN61010 CAT III, 1000 V; CAT IV, 600 V
0-3000 meters per EN61010 CAT II, 1000 V; EN61010 CAT III, 600 V;
CAT IV, 300 V
Storage: 10000 meters
4 AA Alkaline, NEDA 15A or LR6
72 Hours typical (with backlight off)
Per MIL-T-PRF 28800 for Class II instruments
Susceptibility and Emissions: Commercial Limits per EN61326-1
10.0 cm x 20.3 cm x 5.0 cm (3.94 in x 8.00 in x 1.97 in)
(Not Including Accessory Mount)
545 grams (1.2 lbs.)
Lifetime
1 year

Specifications
Feature Summary

Feature Summary
Feature
Dual Digital Displays

Description

Analog Bar Graph

Primary:
50,000 counts
Secondary: 5,000 count
Bar graph: 51 segments, updates 40 times/second

Backlight with 2 brightness levels

Bright white backlight for clear readings in poorly lighted areas

Fast Autorange

Meter automatically selects best range - instantly

AC+DC true rms, ac rms specified to 100 kHz

Choices for AC only, AC and DC dual display, or AC+DC readings

dBm, dBV

User selectable impedance references for dBm

AutoHOLD

Holds readings on display

Continuity / Open test

Beeper sounds for resistance readings below threshold, or to
indicate a momentary open circuit

Fast Bar Graph

51 segments for peaking and nulling

Duty cycle / Pulse width

Measure signal on or off time in % or milliseconds

MIN MAX Mode

Record maximum, minimum, and average values.
24-hour clock for MAX or MIN, elapsed time for AVG.

FAST MN MX with 24-hour time stamp

FAST MN MX captures peaks to 250 µsec.

Closed-Case Calibration

No internal adjustments needed

Battery / Fuse Access Door

Battery or fuse replaceable without voiding calibration

Hi-Impact Overmolded Case

Protective holster features

7-3

Model 187 & 189
Users Manual

Basic Specifications
Function

Ranges/Description

DC Voltage

0 to 1000 V

AC Voltage, true RMS

2.5 mV to 1000 V – 100 kHz bandwidth

Basic Accuracy

DC voltage: 0.025 %
AC voltage: 0.4 %

DC Current

0 to 10 A (20 A for 30 seconds)

AC Current, true RMS

25 µA to 10 A (20 A for 30 seconds)

Resistance

0 to 500 MΩ

Conductance

0 to 500 nS

Capacitance

0.001 nF to 50 mF

Diode Test

3.1 V

Temperature

−200 °C to 1350 °C (−328 °F to 2462 °F)

Frequency

0.5 Hz to 1000 kHz

LOGGING Intervals
(Model 189 only)

At least 288 intervals may be stored. Up to 707 unstable event values (see AutoHold)
are automatically added to LOGGING memory for viewing only through optional PC
software. Additional intervals will be logged up to 995 if the signal is stable.

SAVE Readings
(Model 189 only)

Up to 100 readings may be saved by the user in a memory separate from LOGGING
memory. These readings may be viewed using VIEW MEM.

7-4

Specifications
Detailed Accuracy Specifications

Detailed Accuracy Specifications
Accuracy is specified for a period of one year after calibration, at 18 °C to 28 °C (64 °F to 82 °F), with relative humidity to 90
%. Accuracy specifications are given as:
± ( [ % of reading ] + [ number of least significant digits ] )
AC mV, AC V, AC µA, AC mA, and AC A specifications are ac coupled, true rms and are valid from 5 % of range to
100 % of range. AC crest factor can be up to 3.0 at full-scale, 6.0 at half-scale except the 3000 mV and 1000 V ranges
where it is 1.5 at full scale, 3.0 at half-scale.
Accuracy
Function
AC mV

AC V

dBV

1, 2

Range

Resolution

45 Hz-1 kHz

20-45 Hz

1 kHz-10 kHz

10 kHz-20 kHz 20 kHz-100 kHz

50.000 mV

0.001 mV

0.4 % + 40

2 % + 80

5 % + 40

5.5 % + 40

15 % + 40

500.00 mV

0.01 mV

0.4 % + 40

2 % + 80

5 % + 40

5.5 % + 40

8 % + 40

3000.0 mV

0.1 mV

0.4 % + 40

2 % + 80

0.4 % + 40

1.5 % + 40

8 % + 40

5.0000 V

0.0001 V

0.4 % + 40

2 % + 80

0.4 % + 40

1.5 % + 40

8 % + 40

50.000 V

0.001 V

0.4 % + 40

2 % + 80

0.4 % + 40

1.5 % + 40

8 % + 40

500.00 V

0.01 V

0.4 % + 40

2 % + 80

0.4 % + 40

Not specified

1000.0 V

0.1 V

0.4 % + 40

2 % + 80

0.4 % + 40

Not specified

−52 to −6

0.01 dB

0.1 dB

0.2 dB

0.5 dB

1.4 dB

−6 to +34

0.01 dB

0.1 dB

0.2 dB

0.1 dB

0.2 dB

0.8 dB

+34 to +60

0.01 dB

0.1 dB

0.2 dB

0.1 dB

Not specified

1. For the 5,000 count mode, divide the number of least significant digits (counts) by 10.
2. A residual reading of 8 to 180 digits with leads shorted, will not affect stated accuracy above 5 % of range.

7-5

Model 187 & 189
Users Manual

Accuracy
Function
AC µA

AC mA

AC A

Range

Resolution

45-1 kHz

20-45 Hz

1-20 kHz

500.00 µA

0.01 µA

0.75 % + 20

1 % + 20

0.75 % + 20

6 % + 40

5,000.0 µA

0.1 µA

0.75 % + 5

1% + 5

0.75 % + 10

2 % + 40

50.000 mA

0.001 mA

0.75 % + 20

1% + 20

0.75 % + 20

9 % + 40

400.00 mA

0.01 mA

0.75 % + 5

1% + 5

1.5 % + 10

4 % + 40

5.0000 A

0.0001 A

1.5 % + 20

1.5% + 20

6 % + 40

Not specified

0.001 A

1.5 % + 5

1.5% + 5

5 % + 10

Not specified

10.000 A

1. 10 A continuous up to 35 °C, less than 10 minutes 35 °C to 55 °C. 20 A overload for 30 seconds maximum.

7-6

20 kHz-100 kHz

Specifications
Detailed Accuracy Specifications

Accuracy
Function
DC mV

DC V

DC µA

DC mA

DC A

Range

Resolution

50.000 mV

0.001 mV

0.1% + 20

500.00 mV

0.01 mV

0.03 % + 2

3000.0 mV

0.1 mV

0.025 % + 5

Accuracy Dual Display AC or AC+DC
20 - 45 Hz
2 % + 80

45 Hz - 1 kHz
0.5 % + 40

1 kHz- 20 kHz
6 % + 40

2 % + 40
2

5.0000 V

0.0001 V

0.025 % + 10

50.000 V

0.001 V

0.03 % + 3

500.00 V

0.01 V

0.1 % + 2

Not specified

1000.0 V

0.1 V

0.1 % + 2

500.00 µA

0.01 µA

0.25 % + 20

1 % + 20

1.0 % + 20

2 % + 40

5,000.0 µA

0.1 µA

0.25 % + 2

1 % + 10

0.75 % + 10

2 % + 40

50.000 mA

0.001 mA

0.15 % + 10

1 % + 20

0.75 % + 20

2 % + 40

400.00 mA

0.01 mA

0.15 % + 2

1 % + 10

3 % + 40

5.0000 A

0.0001 A

0.5 %+ 10

2 % + 20

6 % + 40

0.001 A

0.5 %+ 2

1.5 % + 10

5 % + 10

10.000 A

1. 10 A continuous up to 35 °C, less than 10 minutes 35 °C to 55 °C. 20 A overload for 30 seconds maximum.
2. 20 counts in dual display DC or AC+DC.
3. See AC conversions notes for AC mV and V

7-7

Model 187 & 189
Users Manual

Function
Resistance

Conductance

Range

Resolution

Accuracy

500.00 Ω

0.01 Ω

0.05 % + 10

5.0000 kΩ

0.0001 kΩ

0.05 % + 2

50.000 kΩ

0.001 kΩ

0.05 % + 2

500.00 kΩ

0.01 kΩ

0.05 % + 2

5.0000 MΩ

0.0001 MΩ

0.15 % + 4

5.000 MΩ up to 32.000 MΩ

0.001 MΩ

1.0 % + 4

32.0 MΩ up to 50.0 MΩ

0.1 MΩ

3.0 % + 2

50.0 MΩ up to 100.0 MΩ

0.1 MΩ

3.0% + 2

100.0 MΩ up to 500.0 MΩ

0.1 MΩ

10.0 % + 2

50.00 nS

0.01 nS

1 % + 10

1. For the 5,000 count mode, divide the number of least significant digits (counts) by 10.
2. For relative humidity greater than 70 %, resistance accuracy is 0.5 % over 1 MΩ and 2.5 % over 10 MΩ.
3. Using relative mode (REL ∆) to zero residual reading.
4. To ensure stated accuracy, switch to conductance mode and verify that the open circuit reading is less than 0.10 nS.

7-8

Specifications
Detailed Accuracy Specifications

Function
Capacitance

Diode Test

Ranges

Resolution

Accuracy

1.000 nF

0.001 nF

2% + 5

10.00 nF

0.01 nF

1%+5

100.0 nF

0.1 nF

1.000 µF

0.001 µF

10.00 µF

0.01 µF

100.0 µF

0.1 µF

1,000 µF

1 µF

10.0 mF

0.01 mF

50.00 mF

0.01 mF

3.1000 V

0.0001 V

3 % + 10
2 % + 20

1. For the 5,000 count mode, divide the number of least significant digits (counts) by 10.
2. For film capacitor or better, using Relative mode (REL ∆) to zero residual on 1.000 nF and 10.00 nF ranges.
3. Least significant digit not active above 10 mF.

7-9

Model 187 & 189
Users Manual

Function
Frequency

Range

Resolution
1

Accuracy
± (0.0050 % + 1)

500.00 Hz

0.01 Hz

5.0000 kHz

0.0001 kHz

50.000 kHz

0.001 kHz

999.99 kHz

0.01 kHz

Duty Cycle

10.00% to 90.00 %

0.01 %

± ((voltage range/input voltage) X 300 counts)

Pulse Width

499.99 ms

0.01 ms

± (3 % X (voltage range/input voltage) + 1 count)

999.9 ms

0.1 ms

Temperature
MIN MAX AVG

FAST MN MX

−200 to +1350 °C

0.1 °C

± ( 1% of reading + 1 °C)

−328 to +2462 °F

0.1 °F

± ( 1% of reading + 1.8 °F)

Response: 100 ms to 80 %

250 µs

5,6
5,6

2,3
2,3

Specified accuracy ± 12 counts for changes > 200 ms
in duration. (± 40 counts in AC for changes > 350 ms
and inputs > 25 % of range)
Specified accuracy ±100 counts up to 5,000 count (full
range) reading. For higher peak readings (to 20,000
counts), specified accuracy ± 2% of reading.

1. Reading will be 0.00 for signals below 0.5 Hz.
2. Accuracy specification is relative to the user-adjustable temperature offset, and assumes ambient temperature stable to ± 1 °C.
3. For ambient temperature changes of ± 5 °C, rated accuracy applies after 1 hour.
4. For repetitive peaks; 2.5 ms for single events. Use DC function settings below 20 Hz. 50 mV range not specified.
5. Frequency greater than 5 Hz, except for VDC, 500 mVDC and 3000 mVDC functions; 0.5 Hz to 1 kHz. Signals centered around
trigger levels.
6. Range/input ratios also apply to current functions. 500 counts or 5 % for 10 A ranges.

7-10

Specifications
Frequency Counter Sensitivity

Frequency Counter Sensitivity

Input Range
50 mV
500 mV
3000 mV
5V
50 V
500 V
1000 V

Approximate VAC Sensitivity
1
(RMS Sine Wave)
15 Hz to
2
2
100 kHz
500 kHz
5 mV
20 mV
500 mV
0.5 V
5V
20 V
100 V

10 mV
20 mV
2000 mV
2.0 V
5.0 V
20 V
100 V

VAC Bandwidth
1 MHz
1 MHz
800 kHz
950 kHz
1 MHz
1 MHz
> 400 kHz

Approximate VDC
1
Trigger Levels
-5 mV & 5 mV
5 mV & 65 mV
140 mV & 200 mV
1.4 V & 2.0 V
0.5 V & 6.5 V
5 V & 65 V
5 V & 65 V

VDC
3
Bandwidth
1 MHz
1 MHz
90 kHz
14 kHz
> 400 kHz
> 400 kHz
> 400 kHz

. 1. Maximum input = 10 x Range (1000 V max). Noise at low frequencies and amplitudes may affect accuracy.
2. Useable at reduced sensitivity to 0.5 Hz and 1000 kHz.

. 3. Typical frequency bandwidth with full scale (or maximum 2 X 107 V-Hz product) RMS sine wave.

Burden Voltage (A, mA, µA)
Function
mA - µA

Range
500.00 µA

Burden Voltage (typical)
102 µV / µA

5,000 µA

102 µV / µA

50.000 mA

1.8 mV / mA

400.00 mA

1.8 mV / mA

5.0000 A

0.04 V / A

10.000 A

0.04 V / A

7-11

Model 187 & 189
Users Manual

Input Characteristics
Function

Input Impedance (Nominal)

Volts, mV

10 MΩ, < 100 pF
Common Mode Rejection Ratio

DC Volts, mV

>100 dB at dc, 50 Hz or 60 Hz ±0.1%

AC Volts, mV

> 90 dB dc to 60 Hz

Normal Mode Rejection
>90 dB at 50 Hz or 60 Hz ± 0.1%

Full-Scale Voltage
Open Circuit Test Voltage
Ohms

<5V

Diode Test

<5V

To 5 MΩ

30 MΩ + nS

500 mV

3.1 V
3.1000 V

Typical Short-Circuit Current
500 Ω
Ohms
Diode Test

7-12

1 mA

5 kΩ
100 µA

50 kΩ

500 kΩ

10 µA

1 µA

1 mA typical

5 MΩ
0.1 µA

30 MΩ
0.1 µA

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