Fluke 189 User Manual

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 f rom def ects in material and workmanship for its lif et ime. As used herein,

“lifetime” is defined as seven years after Fluke di scontinues manufacturing the product, but the warranty period shall be at least ten years from
the date of purchase. This warranty does not cover fuses , di sposable batteries, damage f rom negl ec t, misuse, contam i nat i on, alteration,
accident or abnormal conditi ons of operation or handling, including f ai l ures 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 als o covers the LCD. Thereafter, for the lifetime of the DMM, Fl uke will replace the
LCD for a fee based on then current component acquisition costs.

To establish original ownership and prove date of purchase, please com pl ete and return the registration card ac companying 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 defec-
tive product purchased through a Fl uke authorized sales outlet and at the applicable international pri c e. Fluke reserves the right to charge
for importation costs of repair/replacement parts i f the product purchased in one country is sent for repair elsewhere.

If the product is defective, contact y our nearest Fluke authorized servi ce center to obtain return authorization information, then send t he
product to that service center, with a descript i on of the difficulty, postage and insurance prepaid (FOB Destination). Fluke assumes no risk
for damage in transit. Fluke will pay return trans portation for product repaired or replaced in-warranty. B ef ore making any non-warranty
repair, Fluke will estimate cost and obt ain authorization, then invoice you for repair and ret urn t rans portation.

THIS WARRANTY IS Y O UR ONLY REMEDY. NO OTHER WARRANTIES, SUCH AS FIT NESS 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 DI FFERENT WARRANTY ON FLUKE’S BE HA LF. Since some states do not allow the exclusion or
limitation of an implied warranty or of incidental or cons equential 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 Fluke Europe B.V.
P.O. Box 9090 P.O. Box 1186
Everett, WA 98206-9090 5602 BD Eindhoven

2/02

U.S.A. The Netherlands

Table of Contents

Chapter Title Page

1 Before You Start .......................................................................................................... 1-1

Safety Information.......................................................................................................... 1-1

Contacting Fluke............................................................................................................ 1-1

Symbols.........................................................................................................................1-4

2 Getting Acquainted...................................................................................................... 2-1

Introduction....................................................................................................................2-1

Turning the Meter On..................................................................................................... 2-1

Battery Considerations .................................................................................................. 2-2

Automatic Power Off................................................................................................. 2-2

Automatic Backlight Off............................................................................................. 2-3

Low Battery Indication............................................................................................... 2-3

Rotary Switch................................................................................................................. 2-4

Pushbuttons................................................................................................................... 2-5

i

Model 187 & 189

Users Manual

Selecting the Range....................................................................................................... 2-10

Understanding the Display............................................................................................. 2-10

Primary Display......................................................................................................... 2-10

Secondary Display..................................................................................................... 2-11

Bar Graph.................................................................................................................. 2-11

Using the Input Terminals.............................................................................................. 2-17

Using Display Hold......................................................................................................... 2-18

Using AutoHOLD............................................................................................................ 2-19

Using MIN MAX.............................................................................................................. 2-19

Using FAST MN MX....................................................................................................... 2-21

Using HOLD with MIN MAX or FAST MN MX............................................................ 2-22

Using Relative Mode (REL)............................................................................................ 2-22

3 Making Measurements................................................................................................. 3-1

Introduction ....................................................................................................................3-1

Measuring Voltage......................................................................................................... 3-1

Measuring AC Voltage............................................................................................... 3-2

dB Measurements in AC Volts Functions.................................................................. 3-3

Measuring DC Voltage.............................................................................................. 3-4

Both AC and DC Voltage Measurements.................................................................. 3-4

Measuring Resistance.................................................................................................... 3-6

Testing for Continuity..................................................................................................... 3-8

Using Conductance for High Resistance Tests.............................................................. 3-9

Measuring Capacitance.................................................................................................. 3-12

Testing Diodes............................................................................................................... 3-13

Measuring Temperature................................................................................................. 3-15

Measuring Current ......................................................................................................... 3-16

Input Alert™ Feature................................................................................................. 3-17

ii

Contents (continued)

Measuring AC Current.............................................................................................. 3-18

Measuring DC Current.............................................................................................. 3-20

Measuring Frequency.................................................................................................... 3-22

Measuring Duty Cycle.................................................................................................... 3-23

Measuring Pulse Width.................................................................................................. 3-25

4 Using Memory & Communications Features ............................................................ 4-1

Introduction....................................................................................................................4-1

Types of Memory........................................................................................................... 4-1

Saved Readings Memory.......................................................................................... 4-1

Logged Readings Memory........................................................................................ 4-1

Storing Saved Readings................................................................................................ 4-2

Starting Logging ............................................................................................................ 4-2

Stopping Logging........................................................................................................... 4-2

Viewing Memory Data.................................................................................................... 4-3

Clearing Memory ........................................................................................................... 4-5

Using Communications (187 and 189) .......................................................................... 4-5

5 Changing the Default Settings ................................................................................... 5-1

Introduction....................................................................................................................5-1

Selecting Setup Options................................................................................................ 5-1

Adjusting the Temperature Offset.................................................................................. 5-4

Selecting Display Resolution (3 1/2 or 4 1/2 Digits)...................................................... 5-6

Setting the Power Off Timeout....................................................................................... 5-6

Setting the 24-Hour Clock.............................................................................................. 5-7

Setting the Line (Main) Frequency................................................................................. 5-7

Returning to Factory Defaults........................................................................................ 5-8

Saving Setup Options.................................................................................................... 5-8

iii

Model 187 & 189

Users Manual

6 Maintenance ................................................................................................................. 6-1

Introduction ....................................................................................................................6-1

General Maintenance..................................................................................................... 6-1

Testing the Fuses........................................................................................................... 6-1

Replacing the Batteries.................................................................................................. 6-3

Replacing the Fuses ...................................................................................................... 6-5

User-Replaceable Parts................................................................................................. 6-5

In Case of Difficulty........................................................................................................ 6-5

7 Specifications............................................................................................................... 7-1

Safety and Compliances................................................................................................ 7-1

Physical Specifications................................................................................................... 7-2

Feature Summary........................................................................................................... 7-3

Basic Specifications....................................................................................................... 7-4

Detailed Accuracy Specifications................................................................................... 7-5

Frequency Counter Sensitivity....................................................................................... 7-11

Burden Voltage (A, mA, µA)........................................................................................... 7-11

Input Characteristics....................................................................................................... 7-12

iv

List of Tables

Table Title Page

1-1. Safety Information................................................................................................................. 1-2

1-2. International Electrical Symbols............................................................................................1-4

2-1. Rotary Switch Selections...................................................................................................... 2-6

2-2. Pushbuttons .......................................................................................................................... 2-8

2-3. Display Features................................................................................................................... 2-13

3-1. Current Measurement........................................................................................................... 3-16

4-1. View Display......................................................................................................................... 4-4

5-1. Function Specific Setup Selections....................................................................................... 5-2

5-2. Common Setup Selections................................................................................................... 5-3

6-1. User-Replaceable Parts........................................................................................................ 6-6

v

Model 187 & 189

Users Manual

vi

List of Figures

Figure Title Page

2-1. AC Volts Display................................................................................................................... 2-2

2-2. Rotary Switch........................................................................................................................ 2-4

2-3. Pushbuttons .......................................................................................................................... 2-5

2-4. Display Features................................................................................................................... 2-12

2-5. Input Terminals..................................................................................................................... 2-17

2-6. Display Hold and AutoHOLD ................................................................................................ 2-18

2-7. Min Max Avg......................................................................................................................... 2-21

2-8. Relative Mode....................................................................................................................... 2-22

3-1. AC Voltage Measurement..................................................................................................... 3-2

3-2. dBm Display.......................................................................................................................... 3-3

3-3. AC and DC Display............................................................................................................... 3-5

3-4. DC Voltage Measurement..................................................................................................... 3-6

3-5. Resistance Measurement..................................................................................................... 3-7

3-6. Continuity Test ............................................................................................................ .......... 3-10

3-7. Conductance Measurement.................................................................................................. 3-11

3-8. Capacitance Measurement................................................................................................... 3-13

3-9. Diode Test ............................................................................................................................ 3-14

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Model 187 & 189

Users Manual

3-10. Temperature Measurement................................................................................................... 3-15

3-11. AC Current Measurement...................................................................................................... 3-19

3-12. DC Current Measurement.....................................................................................................3-21

3-13. Functions Allowing Frequency Measurement........................................................................ 3-22

3-14. Hz Display............................................................................................................................. 3-23

3-15. Duty Cycle Measurements....................................................................................................3-24

3-16. Duty Cycle Display................................................................................................................ 3-25

3-17. Pulse Width Measurements...................................................................................................3-26

3-18. Pulse Width Display .............................................................................................................. 3-27

4-1. View Display.......................................................................................................................... 4-4

5-1. Adjusting Temperature Offset ............................................................................................... 5-5

6-1. Testing the Current Fuses..................................................................................................... 6-2

6-2. Battery and Fuse Replacement............................................................................................. 6-4

viii

Chapter 1

Before You Start

Safety Information

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

• 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.

Contacting Fluke

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

USA: 1-888-99-FLUKE (1-888-993-5853)
Canada: 1-800-36-FLUKE (1-800-363-5853)
Europe: [phone]
Japan: [phone]
Singapore: [phone]
Anywhere in the world: [phone]

Address correspondence to:

Fluke Corporation Fluke Europe B.V.
P.O. Box 9090, P.O. Box 1186,
Everett, WA 98206-9090 5602 BD Eindhoven
USA 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:

• 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.

1-2

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

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

AC (Alternating Current) Earth ground

DC (Direct Current) Fuse

AC and DC Double insulated

Battery Important information

1-4

Complies with relevant Canadian
Standards Association directives

Inspected and licensed by TÜV Product
Services.

Complies with European Union directives

Underwriters Laboratories, Inc.

Chapter 2

Getting Acquainted

Introduction

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:

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

• Logging

• Save

• Memory

Turning the Meter On

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

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

tc031f.eps

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.

Automatic Power Off

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.

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.

2-2

Getting Acquainted

Battery Considerations

2

Automatic Backlight Off

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.

Note

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

Low Battery Indication

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

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

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.

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

nS

F

C

mA

ac+dc

VIEW MEM

CLEAR MEM

A

mA

ac+dc

A

A

A

tc012f.eps

mV

dB

V

dB

V

ac+dc

OFF

mV

ac+dc

Figure 2-2. Rotary Switch

2-4

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).

Getting Acquainted

Pushbuttons

AutoHOLD

SETUP

FAST MN MX

MIN MAXHOLD

MIN MAXHOLD

ms

ms

Hz

Hz

%

%

LOGGING

REL

REL

SAVECANCEL

RANGE

RANGE

YES

NO

tc013f.eps

Figure 2-3. Pushbuttons

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

2

2-5

Model 187 & 189

Users Manual

Table 2-1. Rotary Switch Selections

Position Rotary Switch Function % Blue Key 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

$

DC millivolt measurement from 0 mV to 3000.0 mV AC over DC (AC in primary display, DC in secondary

m

Resistance measurement from 0 Ω to 500.0 MΩ Continuity test

j

Capacitance measurement from 0.001 nF to 50 mF Diode test

display), DC over AC, ac+dc

display), DC over AC, ac+dc

Conductance measurement from 0 nS to 50.00 nS

z

2-6

Temperature measurement Toggles between °C and °F.

w

Getting Acquainted

Table 2-1. Rotary Switch Positions (cont.)

Position Rotary Switch Function % Blue Key Function

AC current measurements from 0 mA to 20.000 A none

I

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

K

DC current measurements from 0 µA to 5000.0 µA AC over DC (AC in primary display, DC in secondary

x

display), DC over AC, ac+dc

display), DC over AC, ac+dc

Pushbuttons

2

VIEW
MEM

(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.

2-7

Model 187 & 189

Users Manual

Table 2-2. Pushbuttons

Yellow Button

Button Description

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.

Q Press to freeze the displayed value. Press again to

release the display.

M Press to start retaining min, max, and average values.

Press successively to display max, min, and average
values. Press O N (CANCEL) to stop.

D 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.

2-8

SETUP

O T

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.

Table 2-2. Pushbuttons (cont.)

Button Description

[

]

R Exit AUTO and enter MANUAL ranging. In MANUAL,

• 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).

select next input range. Press O N
(CANCEL) to return to AUTO.

Getting Acquainted

Yellow Button

Function Description

(none)

(none)

SAVE

O R

Press to save present reading
(Model 189)

Pushbuttons

2

N Successively press for frequency, duty cycle, and

pulse width.

%

s

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.

CANCEL

O N

(none)

CANCEL any % (blue key) function
and all other button features.

2-9

Model 187 & 189

Users Manual

Selecting the Range

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

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).

Understanding the Display

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

Note

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.

2-10

Getting Acquainted

Understanding the Display

2

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

• REL: the difference between the present reading and

a stored reference reading.

• Setup: various messages (see Chapter 5).

• Overload conditions: OL displayed.

• Error conditions.

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.

Bar Graph

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.

2-11

Model 187 & 189

Users Manual

8

10

9

12

117

6

5

13

4

3

2

1

14

16 1517

Figure 2-4. Display Features

tc011f.eps

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.

 p Percent difference in Relative mode is being displayed in the primary display. The

reference value is shown in the secondary display

 e 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.

 Z >30 V ac and/or dc may be present at the input terminals.
 B 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

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

 ; Readings are being recorded in memory (Model 189 only.) ( O + D)
 g The meter is in Hold mode. ( Q)
 gS AutoHOLD is active. ( O + Q)


8.8.8.8.8
0L

Primary Displa y (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).

2-14

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.

2

e, ke Me, Ω: Ohm. The unit of resistance.

kΩ: Kilohm. 1 x 10
MΩ: Megohm. 1 x 10

3

or 1000 ohms.

6

or 1,000,000 ohms.

nS S: Siemens. The unit of conductance.

nS: Nanosiemens. 1 x 10

-9

or 0.000000001 Siemens.

nF, µF, mF F: Farad. The unit of capacitance.

nF: Nanofarad. 1 x 10
µF: Microfarad. 1 x 10
mF: Millifarad. 1 X 10

-9

or 0.000000001 farads.

-6

or 0.000001 farads.

-3

or 0.001 farads.

°C ,°F Degrees Celsius (default) or Fahrenheit.
A, mA, µA A: Amperes (amps). The unit of current.

mA: Milliamp. 1 x 10
µA: Microamp. 1 x 10

-3

or 0.001 amperes.

-6

or 0.000001 amperes.

Hz, kHz, MHz Hz: Hertz. The unit of frequency.

kHz: Kilohertz. 1 x 10
MHz: Megahertz. 1 x 10

3

or 1000 hertz.

6

or 1,000,000 hertz.

2-15