Fluke 787B Operating Manual

August 2002, Rev. 4, 1/17

© 2002-2017 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.

789/787B

ProcessMeter™

Users Manual

LIMITED WARRANTY AND LIMITATION OF LIABILITY

This Fluke product will be free from defects in material and workmanship for three years from the date of purchase. This war­ranty does not cover fuses, disposable batteries, or damage from accident, neglect, misuse, alteration, contamination, or
abnormal conditions of operation or handling. Resellers are not authorized to extend any other warranty on Fluke’s behalf.
To obtain service during the warranty period, contact your nearest Fluke authoriz ed service center to obtain return authoriza­tion information, then send the product to that Service Center with a description of the problem.

THIS WARRANTY IS YOUR ONLY REMEDY. NO OTHER WARRANTIES, SUCH AS FITNESS FOR A PARTICULAR
PURPOSE, ARE EXPRESSED OR IMPLIED. FLUKE IS NOT LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
CONSEQUENTIAL DAMAGES OR LOSSES, ARISING FROM ANY CAUSE OR THEORY. Since some states or countries
do not allow the exclusion or limitation of an implied warranty or of incidental or consequ ential damages, this limitation of
liability may not apply to you.

Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.

11/99

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

Table of Contents

Title Page

Introduction .................................................................................................................... 1

How to Contact Fluke ..................................................................................................... 2

Safety Information .......................................................................................................... 2

How to Get Started ......................................................................................................... 6

Getting Acquainted with the Meter ................................................................................. 7

Measuring Electrical Parameters .................................................................................... 18

Input Impedance ........................................................................................................ 18

Ranges ...................................................................................................................... 18

Testing Diodes ........................................................................................................... 18

Displaying Minimum, Maximum, and Average ........................................................... 19

Using AutoHold .......................................................................................................... 19

Compensating for Test Lead Resistance ................................................................... 20

Using the Current Output Functions ............................................................................... 20

Source Mode ............................................................................................................. 20

Simulate Mode ........................................................................................................... 22

Producing a Steady mA Output ................................................................................. 24

Manually Stepping the mA Output ............................................................................. 25

Auto Ramping the mA Output .................................................................................... 26

i

789/787B

Users Manual

Power-Up Options ......................................................................................................... 26

Loop Power Supply Mode (789 only) ............................................................................. 28

Battery Life ..................................................................................................................... 30

Maintenance .................................................................................................................. 30

Calibration ................................................................................................................. 31

Replacing the Batteries ............................................................................................. 31

Replacing a Fuse ...................................................................................................... 33

If the Meter does not Work ........................................................................................ 34

Replacement Parts and Accessories ............................................................................. 34

Specifications ................................................................................................................. 38

ii

ProcessMeter

Introduction

Warning

Read “Safety Information” before using the
meter.

The Fluke 789/787B ProcessMeter (the Meter or
Product) is a handheld, battery-operated tool for
measuring electrical parameters and supplying steady or
ramping current to test process instruments. All
illustrations in this manual show the 789 model.

The 789 adds a 24 V loop power supply. It has all the
features of a digital multimeter, plus current output
capability.

If the meter is damaged or something is missing, contact
the place of purchase immediately. Contact a Fluke
distributor for information about DMM (digital multimeter)
accessories. To order replacement parts or spares, see
Table 13 near the end of this manual.

1

789/787B

Users Manual

How to Contact Fluke

To contact Fluke, call one of the following telephone
numbers:

• Technical Support USA: 1-800-44-FLUKE
(1-800-443-5853)

• Calibration/Repair 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]

Or, visit Fluke's website at www.fluke.com.
To register your product, visit http://register.fluke.com.
To view, print, or download the latest manual supplement,

visit http://us.fluke.com/usen/support/manuals.

Safety Information

A Warning identifies conditions and procedures that are
dangerous to the user. A Caution identifies conditions and
procedures that can cause damage to the Product or the
equipment under test.

International symbols used on the meter and in this
manual are explained in Table 1.

Warning

To prevent possible electrical shock, fire, or
personal injury:

• Read all safety information before you use the

Product.

• Carefully read all instructions.

• Do not alter the Product and use only as

specified, or the protection supplied by the
Product can be compromised.

• Remove the batteries if the Product is not

used for an extended period of time, or if
stored in temperatures above 50 °C. If the
batteries are not removed, battery leakage
can damage the Product.

2

ProcessMeter™

Safety Information

• The battery door must be closed and locked

before you operate the Product.

• Replace the batteries when the low battery

indicator shows to prevent incorrect
measurements.

• Comply with local and national safety codes.

Use personal protective equipment (approved
rubber gloves, face protection, and flame­resistant clothes) to prevent shock and arc
blast injury where hazardous live conductors
are exposed.

• Do not apply more than the rated voltage,

between the terminals or between each
terminal and earth ground.

• Do not work alone.

• Limit operation to the specified measurement

category, voltage, or amperage ratings.

• Use Product-approved measurement category

(CAT), voltage, and amperage rated
accessories (probes, test leads, and adapters)
for all measurements.

• Measure a known voltage first to make sure

that the Product operates correctly.

• Use the correct terminals, function, and range

for measurements.

• Do not touch voltages > 30 V ac rms, 42 V ac

peak, or 60 V dc.

• Do not use the Product around explosive gas,

vapor, or in damp or wet environments.

• Do not use the Product if it operates

incorrectly.

• Examine the case before you use the Product.

Look for cracks or missing plastic. Carefully
look at the insulation around the terminals.

• Do not use test leads if they are damaged.

Examine the test leads for damaged
insulation, exposed metal, or if the wear
indicator shows. Check test lead continuity.

3

789/787B

Users Manual

• Keep fingers behind the finger guards on the

probes.

• Only use probes, test leads, and accessories

that have the same measurement category,
voltage, and amperage ratings as the Product.

• Remove all probes, test leads, and

accessories before the battery door is
opened.

• Remove all probes, test leads, and

accessories that are not necessary for the
measurement.

• Do not exceed the Measurement Category

(CAT) rating of the lowest rated individual
component of a Product, probe, or accessory.

• Do not use test leads if they are damaged.

Examine the test leads for damaged
insulation and measure a known voltage.

• Do not use a current measurement as an

indication that a circuit is safe to touch. A
voltage measurement is necessary to know if
a circuit is hazardous.

• Do not use the Product if it is altered or

damaged.

• Do not use in CAT III or CAT IV environments

without the protective cap installed on test
probe. The protective cap decreases the
exposed probe metal to <4 mm. This
decreases the possibility of arc flash from
short circuits.

4

ProcessMeter™

Safety Information

Table 1. International Symbols

Symbol Description Symbol Description






















5

WARNING. RISK OF DANGER.

Consult user documentation.

Conforms to European Union directives
Certified by CSA Group to North American safety

standards.
AC (Alternating Current)

DC (Direct Current)
Battery

Measurement Category II is applicable to test and measuring circuits connected directly to utilization points
(socket outlets and similar points) of the low-voltage MAINS installation.

Measurement Category III is applicable to test and measuring circuits connected to the distribution part of the
building’s low-voltage MAINS installation.

Measurement Category IV is applicable to test and measuring circuits connected at the source of the building’s
low-voltage MAINS installation.

This product complies with the WEEE Directive marking requirements. The affixed label indicates that you must not
discard this electrical/electronic product in domestic household waste. Product Category: With reference to the
equipment types in the WEEE Directive Annex I, this product is classed as category 9 "Monitoring and Control
Instrumentation" product. Do not dispose of this product as unsorted municipal waste.















WARNING. HAZARDOUS VOLTAGE. Risk
of electric shock.

Conforms to relevant South Korean EMC
Standards

Minimum fuse interrupt rating.
Conforms to relevant Australian Safety and

EMC standards.
Earth

Fuse
Double Insulated

789/787B

Users Manual

How to Get Started

Warning

To prevent possible electrical shock, fire, or
personal injury:

• Disconnect power and discharge all high-

voltage capacitors before you measure
resistance, continuity, capacitance, or a diode
junction.

• Remove circuit power before you connect the

Product in the circuit when you measure
current. Connect the Product in series with
the circuit.

• Do not use the HOLD function to measure

unknown potentials. When HOLD is turned
on, the display does not change when a
different potential is measured.

If familiar with the Fluke 80 Series DMM, read “Using the
Current Output Functions,” review the tables and figures in
“Getting Acquainted with the Meter,” and begin using the
meter.

If unfamiliar with Fluke 80 Series DMMs, or DMMs in
general, read “Measuring Electrical Parameters” in
addition to the sections referenced in the previous
paragraph.

The sections following “Using the Current Output
Functions” contain information about the power-up options,
and battery and fuse replacement instructions.

See Table 2 for an overview of the meter.

6

ProcessMeter™

Getting Acquainted with the Meter

Table 2. 789/787B ProcessMeter

1

3

2

0%

4

anw014f.eps

Item Description

 Display
 Rotary switch
 Pushbuttons
 Input/Output jacks

Getting Acquainted with the Meter

To become familiar with the features and functions of the
meter, study these tables:

• Table 3 describes the input/output jacks.

• Table 4 describes the input functions of the first six

rotary function switch positions.

• Table 5 describes the output functions of the last
three rotary function switch positions.

• Table 6 describes the functions of the pushbuttons.

• Table 7 explains what all the elements of the display

indicate.

7

789/787B

Users Manual

Table 3. Input/Output Jacks

1

A

mA

2

COM

V

4

3

anw001f.eps

Item Jack Measurement Functions Source Current Function Simulate Transmitter Function

 A c

 mA d



V

Input for current to 440 mA
continuous. (1 A for up to
30 seconds.) Fused with a
440 mA fuse.

Input for current to 30 mA.
Fused with a 440 mA fuse.

Input for voltage to 1000 V, Ω,
continuity, and diode test.

Output for dc current to 24
mA. Output for loop power
supply (789 only).

Common for dc current output
to 24 mA. Common for loop
power supply.

Output for transmitter simulation to
24 mA. (Use in series with an
external loop supply.)

Common for transmitter simulation

 COM Common for all measurements.

to 24 mA. (Use in series with an
external loop supply.)

8

ProcessMeter™

Getting Acquainted with the Meter

Table 4. Rotary Function Switch Positions for Measurements

4

3

2

1

No. Position Function(s) Pushbutton Actions

 OFF

 S

Meter off
Default:

Measure ac V

h

Frequency counter

M Selects a MIN, MAX, or AVG action
R Selects a fixed range (hold 1 second for auto range)
H Toggles AutoHold

5

6

r Toggles relative reading (sets a relative zero point)

anw002f.eps

9

789/787B

Users Manual

No. Position Function(s) Pushbutton Actions









T

U

V

W

Table 4. Rotary Function Switch Positions for Measurements (cont.)

Default:
Measure dc V

Same as above

h

Frequency counter
Default:
Measure dc mV

Same as above (mV has only one range)

h

Frequency counter
Default: Measure Ω

Same as above (diode test has only one range)

G for continuity

J (Blue) D test

High test lead in cA: Measure
A dc

J (Blue) selects ac
High test lead in dmA:

Measure mA dc

Same as above (only one range for each input jack position,
30 mA or 1 A)

10

ProcessMeter™

Getting Acquainted with the Meter

Table 5. Rotary Function Switch Positions for mA Output

1

2

3

No. Position Default Function Pushbutton Actions

% STEP X or W: Adjusts output up or down to the next 25 % step

COARSE X or W: Adjusts output up or down 0.1 mA
FINE X or W: Adjusts output up or down 0.001 mA

 sets output to 0 %
 sets output to 100 %



OUTPUT

X

Test leads in
SOURCE:

Source 0 % mA

Test leads in SIMULATE:

Sink 0 % mA

anw008f.eps

11

789/787B

Users Manual

No. Position Default Function Pushbutton Actions





OUTPUT

Y

monp

250
HART

mA

LOOP POWER

(789 only)

Table 5. Rotary Function Switch Positions for mA Output (cont.)

Test leads in
SOURCE:

Source repeating
0 % -100 %-0 %
slow ramp (m)

Test leads in SIMULATE:

Sink repeating
0 % -100 %-0 %
slow ramp (m)

Test leads in SOURCE:
Supply 24 V loop power,

measure mA

J (Blue) cycles through:

• Fast repeating 0 % -100 % - 0 % ramp (o on display)

• Slow repeating 0 % -100 % - 0 % ramp in 25 % steps (n on

display)

• Fast repeating 0 % -100 % - 0 % ramp in 25 % steps ( pon
display)

• Slow repeating 0 % -100 % - 0 % ramp (m on display)

J (Blue) cycles through:

• 250 Ω series resistor for HART communication switched in

• 250 Ω series resistor switched out

12

ProcessMeter™

Getting Acquainted with the Meter

Table 6. Pushbuttons

No. Pushbutton Function

3

2

4 5

MIN MAX

100%

0%

1

RANGE HOLD

REL

Hz

910

8

7

anw003f.eps

 K Set the backlight to low, high, and off

6





Span Check




Span Check





M

% STEP

mA Output: Adjusts mA output to 0 %
value (4 mA or 0 mA)

mA Output: Sets mA output to 100 %
value (20 mA)

Measuring: Selects a MIN, MAX, or
AVG action

mA Output: Adjusts mA output up to
the next higher 25 % step





R

COARSE

Measuring: Selects a fixed range (hold
for 1 second for auto range)

mA Output: Adjusts output up 0.1 mA

13

789/787B

Users Manual

No. Pushbutton Function







H

FINE
FINE

h



Table 6. Pushbuttons (cont.)

Measuring: Toggles AutoHold, or in MIN MAX recording, suspends recording
mA Output: Adjusts output up 0.001 mA

Measuring: Toggles between frequency counter and voltage measurement functions
mA Output: Adjusts output down 0.001 mA

14







J

(BLUE)

(alternate

function)

COARSE

r



% STEP

G



Rotary function switch in
ac and dc ampere measure

Rotary function switch in V
Rotary function switch in OUTPUT Ymonp position: cycles through

• Slow repeating 0 % -100 % - 0 % ramp (m on display)

• Fast repeating 0 % -100 % - 0 % ramp (o on display)

• Slow repeating 0 % -100 % - 0 % ramp in 25 % steps (p on display)

• Fast repeating 0 % - 100 % - 0 % ramp in 25 % steps (pon display)

Rotary function switch in loop supply position (789 only)

• Switch in/out 250 Ω series resistor

Measuring: Toggles relative reading (sets a relative zero point)
mA Output: Adjusts output down 0.1 mA

Measuring: Toggles between Ω measure and continuity functions
mA Output: Adjusts mA output down to the next lower 25 % step

Wposition and test lead plugged into Ac jack: Toggles between

position: Toggles diode test function (D)

ProcessMeter™

Getting Acquainted with the Meter

Table 7. Display

9

8

7

6

5

4

3

2

11

10

1

12

17

16

13

14

15

No. Element Meaning



% (Percentage display)

 OUTPUT
 S

Shows the mA measured value or output level in %, in a 0-20 mA or 4-20 mA scale
(change scales with power-up option)

Lights when mA output (source or simulate) is active
Lights in continuity function

anw004f.eps

15

789/787B

Users Manual

Table 7. Display (cont.)

No. Element

 

 
 b
 q
 Numerals

 lI

 D
 I

N MAX



 MkΩkHzmAV ACDC

MINAVG

Meaning

Lights when dangerous voltage is detected
Lights when relative reading is on
Lights when the battery is low
Lights when the meter is transmitting or receiving over the IR port
Show the input or output value
Lights when AutoHold is on
Lights in diode test function
Lights when MIN MAX recording is held

MIN MAX recording status indicators:

N - MIN MAX recording is on
MAX - the display is showing the maximum-recorded value
MIN - the display is showing the minimum-recorded value
AVG - the display is showing the average value

Show the input or output units and multipliers associated with the numerals

16

ProcessMeter™

Getting Acquainted with the Meter

Table 7. Display (cont.)

No. Element

Auto Range






 Loop Power

Manual Range

400100030

mV

mo np

250 Ω
HART

Meaning

Range status indicators:

Auto Range - autoranging is on
Manual Range - the range is fixed

The number plus the unit and multiplier indicate the active range.

One of these lights in mA ramping or step output (rotary function switch position

Ymo np):

m - slow continuous 0 % - 100 % - 0 % ramping (40 seconds)
o - fast continuous 0 % - 100 % - 0 % ramping (15 seconds)
n - slow ramp in 25 % steps (15 seconds/step)
p - fast ramp in 25 % steps (5 seconds/step)

Lights when 250 Ω series resistance is switched in (789 only)
Lights when in loop supply mode (789 only)

17

789/787B

Users Manual

Measuring Electrical Parameters

The proper sequence for taking measurements is:

1. Plug the test leads into the appropriate jacks.

2. Set the rotary function switch to the desired function.

3. Touch the probes to the test points.

4. View the results on the LCD display.

Input Impedance

For the voltage measurement functions, input impedance
is 10 MΩ. See "Specifications" for more information.

Ranges

A measurement range determines the highest value and
resolution at which the meter can measure. Most meter
measurement functions have more than one range (see
"Specifications").

Make sure the correct range is selected:

• If the range is too low, the display shows OL
(overload).

• If the range is too high, the meter will not be
displaying its most precise measurement.

The meter normally selects the lowest range that will
measure the applied input signal (Auto Range showing on
the display). Press R to lock the range. Each time
R is pressed, the meter selects the next higher range.
At the highest range, it returns to the lowest range.

If the range is locked, the meter resumes auto ranging
when it is changed to another measurement function or
when R is pressed and held for 1 second.

Testing Diodes

To test a single diode:

1. Insert the red test lead into the Vjack and
black test lead into the COM jack.

2. Set the rotary function switch to

3. Press J (Blue) so that the D symbol is on the
display.

4. Touch the red probe to the anode and the black
probe to the cathode (side with band or bands). The
meter should indicate the appropriate diode voltage
drop.

5. Reverse the probes. The meter displays OL,
indicating high impedance.

The diode is good if it passes the tests in steps 4
and 5.

V.

18

ProcessMeter™

Measuring Electrical Parameters

Displaying Minimum, Maximum, and Average

MIN MAX recording stores the lowest and highest
measurements, and maintains the average of all
measurements.

Press M to turn on MIN MAX recording. Readings are
stored until the meter is turned off, switched to another
measurement or source function, or MIN MAX is turned
off. The beeper sounds when a new maximum or
minimum is recorded. Auto power-off is disabled and auto
ranging is turned off during MIN MAX recording.

Press M again to cycle through the MAX, MIN, and
AVG displays. Press and hold M for 1 second to erase
stored measurements and exit.

In MIN MAX recording, press H to suspend recording;
press H again to resume recording.

Using AutoHold

Note

MIN MAX recording must be off to use AutoHold.

! Warning

To avoid possible electric shock, do not use
AutoHold to determine if dangerous voltage
is present. AutoHold will not capture
unstable or noisy readings.

Activate AutoHold to freeze the meter's display on each
new stable reading (except in the frequency counter
mode). Press H to activate AutoHold. This feature
allows measurements to be taken in situations in which it
is difficult to look at the display. The meter beeps and
updates the display with each new stable reading.

19

789/787B

Users Manual

Compensating for Test Lead Resistance

Use the relative reading feature (Q on the display) to set
the present measurement as a relative zero. A common
use for this feature is to compensate for test lead
resistance when measuring ohms.

Select the Ω measure function, touch the test leads
together, and then press r. Until r is pressed
again, or the meter is switched to another measurement
or source function, the readings on the display will
subtract the lead resistance.

Using the Current Output Functions

The meter provides steady, stepped, and ramped current
output for testing 0-20 mA and 4-20 mA current loops.
Choose source mode, in which the meter supplies the
current, simulate mode, in which the meter regulates

current in an externally powered current loop, or loop
supply mode, where the meter powers an external device
and measures the loop current.

Source Mode

Source mode is selected automatically by inserting the
test leads into the SOURCE + and − jacks as shown in
Figure 1. The arrows show the conventional current flow.
Use source mode whenever it is necessary to supply
current into a passive circuit such as a current loop with
no loop supply. Source mode depletes the battery faster
than simulate mode, so use simulate mode whenever
possible.

The display looks the same in source and simulate
modes. The way to tell which mode is in use is to see
which pair of output jacks is in use.

20

ProcessMeter™

Using the Current Output Functions

PROCESSMETER

789

40

60

20

0

RANGE HOLD

MIN MAX

100%

0%

REL

Hz

80

100

anw010f.eps

Figure 1. Sourcing Current

21

789/787B

Users Manual

Simulate Mode

Simulate mode is so named because the meter simulates
a current loop transmitter. Use simulate mode when an
external dc voltage of 15 to 48 V is in series with the
current loop under test.

Caution

Set the rotary function switch to one of the
mA output settings BEFORE connecting the
test leads to a current loop. Otherwise, a low
impedance from the other rotary function
switch positions could be presented to the
loop, causing up to 35 mA to flow in the loop.

Simulate mode is selected automatically by inserting the
test leads into the SIMULATE + and − jacks as shown in
Figure 2. The arrows show the conventional current flow.
Simulate mode conserves battery life, so use it instead of
source mode whenever possible.

The display looks the same in source and simulate
modes. The way to tell which mode is in use is to see
which pair of output jacks is in use.

Changing the Current Span

The meter’s current output span has two settings (with
overrange to 24 mA):

• 4 mA = 0 %, 20 mA = 100 % (factory default)

• 0 mA = 0 %, 20 mA = 100 %

To find out which span is selected, turn the rotary function
switch to OUTPUT mA [, short the OUTPUT SOURCE +
and − jacks, and observe the 0 % output level.

To toggle and save the current output span in nonvolatile
memory (retained when the power is turned off):

1. Turn off the meter.

2. Hold down R while turning the meter on.

3. Wait at least 2 seconds until the new range shows as
0-20 or 4-20 and then release R.

22

ProcessMeter™

Using the Current Output Functions

dc V

Power Supply

COM +24V

789

PROCESSMETER

40

60

20

80

0

RANGE HOLD

MIN MAX

100%

0%

REL

Hz

100

anw011f.eps

Figure 2. Simulating a Transmitter

23

789/787B

Users Manual

Producing a Steady mA Output

When the rotary function switch is in the OUTPUT mA [
position, and the OUTPUT jacks are connected to an
appropriate load, the meter produces a steady mA dc
output. The meter begins sourcing or simulating 0 %. Use
the pushbuttons to adjust the current as shown in Table 8.

Select either sourcing or simulating by choosing the
SOURCE or SIMULATE output jacks.

If the meter cannot deliver the programmed current
because the load resistance is too high or the loop supply
voltage is too low, dashes (-----) appear on the numeric
display. When the impedance between the SOURCE
jacks is low enough, the meter will resume sourcing.

Note

The STEP pushbuttons described Table 9 are
available when the meter is producing a steady
mA output. The STEP pushbuttons go to the
next multiple of 25 %.

Table 8. mA Output Adjust Pushbuttons

Pushbutton Adjustment

X

Adjusts up 0.1 mA

R

COARSE

X

Adjusts up 0.001 mA

M

FINE
FINE

Adjusts down 0.001 mA

h

W

COARSE

Adjusts down 0.1 mA

r

W

24

ProcessMeter™

Using the Current Output Functions

Manually Stepping the mA Output

When the rotary function switch is in the OUTPUT mA [
position, and the OUTPUT jacks are connected to an
appropriate load, the meter produces a steady mA dc
output. The meter begins sourcing or simulating 0 %. Use
the pushbuttons to step the current up and down in 25 %
increments as shown in Table 9. See Table 10 for mA
values at each 25 % step.

Select either sourcing or simulating by choosing the
SOURCE or SIMULATE output jacks.

If the meter cannot deliver the programmed current
because the load resistance is too high or the loop supply
voltage is too low, dashes (-----) appear on the numeric
display. When the impedance between the SOURCE
jacks is low enough, the meter will resume sourcing.

Note

The COARSE and FINE adjustment pushbuttons
described in Table 8 are available when
manually stepping the mA output.

Table 9. mA Stepping Pushbuttons

Pushbutton Adjustment

X

M

% STEP
% STEP

G

W



Span Check
Span Check



Value (for each span setting)

Step 4 to 20 mA 0 to 20 mA

0 % 4.000 mA 0.000 mA
25 % 8.000 mA 5.000 mA
50 % 12.000 mA 10.000 mA
75 % 16.000 mA 15.000 mA
100 % 20.000 mA 20.000 mA
120 % 24.000 mA
125 % 24.000 mA

Adjusts up to the next higher 25 %
step

Adjusts down to the next lower
25 % step

Sets to 100 % value

Sets to 0 % value

Table 10. mA Step Values

25

789/787B

Users Manual

Auto Ramping the mA Output

Auto ramping gives the ability to continuously apply a
varying current stimulus from the meter to a transmitter,
while hands remain free to test the response of the
transmitter. Select either sourcing or simulating by
choosing the SOURCE or SIMULATE jacks.

When the rotary function switch is in the OUTPUT
Ymonp position, and the output jacks are
connected to an appropriate load, the meter produces a
continuously repeating 0 % - 100 % - 0 % ramp in a
choice of four ramp waveforms:

m 0 % - 100 % - 0 % 40-second smooth ramp

(default)

o 0 % - 100 % - 0 % 15-second smooth ramp
n 0 % - 100 % - 0 % Stair-step ramp in 25 % steps,

pausing 15 seconds at each step. Steps listed in
Table 10.

p 0 % - 100 % - 0 % Stair-step ramp in 25 % steps,

pausing 5 seconds at each step. Steps are listed in
Table 10.

The ramp times are not adjustable. Press J (Blue) to
cycle through the four waveforms.

Note

At any time during auto ramping, the ramp can
be frozen simply by moving the rotary function
switch to the mA [ position. Then the COARSE,
FINE, and % STEP adjust pushbuttons can be
used to make adjustments.

Power-Up Options

To select a power-up option:

1. Push and hold the pushbutton shown in Table 11.

2. Turn the rotary function switch from OFF to the
position listed in Table 11.

3. Wait 2 seconds before you release the pushbutton
after powering up the Meter.

The setting for current span, backlight, and beeper is
retained when the power is turned off. You must repeat
the other options for each operating session.

26

ProcessMeter™

Power-Up Options

Table 11. Power-Up Options

Option Button

Current Span R All Retains setting  -  or  - 

Backlight Timeout K All Retains setting   /  
Beeper G All Retains setting   /   Enables/Disables beeper

Auto Power-Off

Note: Auto power-off is
always disabled when
MIN MAX recording is on.

LCD segments H

Firmware version H VDC Disabled ex: 

Model number H mVDC Disabled ex: 
Go to Calibration mode H Ω Disabled  Calibration mode starts

J
(Blue)

Switch

Position

All Enabled

VAC, mA,
Source,
Ramp,
Loop

Default Display Action Taken

Toggles between 0-20 mA and
4-20 mA range

Enables/Disables the auto-off
on backlight after 2 minutes

Disables the feature that turns



Disabled All segments

off the power after 30 minutes
of inactivity.

Display HOLD (as long as
button pushed)

Display firmware version (as
long as button is pushed)

Display model number (as long
as button is pushed)

27

789/787B

20

22

24

26

28

30

32

0 4 8 12162024

Voltage (V)

Current (mA)

Loo p Vol tage w/o 250 Ω Loo p Vol tage w/ 250 Ω

Users Manual

Loop Power Supply Mode (789 only)

The Loop Power Supply Mode can be used for powering
up a process instrument (transmitter). While in Loop
Power Mode, the meter acts like a battery. The process
instrument regulates the current. At the same time, the
meter measures the current that the process instrument is
drawing.

The meter supplies loop power at a nominal 24 V dc. An
internal series resistance of 250 Ω can be switched in for
communication with HART and other smart devices by
pressing J (Blue). See Figure 3. Pressing J (Blue)
again switches out this internal resistance.

When loop power is enabled, the meter is configured to
measure mA and >24 V dc is sourced between the mA
and A jacks. The mA jack is the common and the A jack is
at >24 V dc. Connect the meter in series with the
instrument current loop. See Figure 4.

Figure 3. Loop Power Voltage vs. Current

anw020f.eps

28

ProcessMeter™

Loop Power Supply Mode (789 only)

PROCESSMETER

789

RANGE HOLD

MIN MAX

100%

0%

REL

Hz

TEST DC PWR

+–+–

–+

anw009f.eps

Figure 4. Connections for Supplying Loop Power

29

789/787B

Users Manual

Battery Life

Warning

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

Table 12 shows typical alkaline battery life. To preserve
battery life:

• Use current simulation instead of sourcing when
possible.

• Avoid using the backlight.

• Do not disable the automatic power-off feature.

• Turn the meter off when not in use.

Table 12. Typical Alkaline Battery Life

Meter Operation Hours

Measuring any parameter 140
Simulating Current 140
Sourcing 12 mA into 500 Ω 10

Maintenance

This section provides some basic maintenance
procedures. Repair, calibration, and servicing not covered
in this manual must be performed by qualified personnel.
For maintenance procedures not described in this manual,
contact a Fluke Service Center.

Periodically wipe the case with a damp cloth and
detergent; do not use abrasives or solvents.

Warning

To prevent possible electrical shock, fire, or
personal injury:

• Do not put battery cells and battery packs

near heat or fire. Do not put in sunlight.

• Replace a blown fuse with exact replacement

only for continued protection against arc
flash.

• Do not operate the Product with covers

removed or the case open. Hazardous voltage
exposure is possible.

• Use only specified replacement parts.

• Use only specified replacement fuses.

• Have an approved technician repair the

Product.

30

ProcessMeter™

Maintenance

Calibration

Calibrate the meter once a year to ensure that it performs
according to its specifications. Contact a Fluke Service
Center for instructions.

Replacing the Batteries

 Warning

For safe operation and maintenance, repair
the Product before use if the battery leaks.

To replace the batteries:

1. Remove the test leads and turn the Meter OFF. See
Figure 5.

2. With a standard blade hand screwdriver, turn each
battery door screw counterclockwise so that the slot is
parallel with the screw picture molded into the case.

3. Lift off the battery door.

4. Remove the meter's batteries.

5. Replace with four new AA alkaline batteries.

6. Reinstall the battery door and tighten screws.

31

789/787B

Users Manual

F2

32

F1

Figure 5. Replacing the Batteries and Fuses

anw037.eps

ProcessMeter™

Maintenance

Replacing a Fuse

! Warning

To avoid personal injury or damage to the
meter, use only the specified replacement
fuse, 440 mA 1000 V fast-blow, Fluke PN

943121.

Both current input jacks are fused with separate 440 mA
fuses. To determine if a fuse is blown:

1. Turn the rotary function switch to

2. Plug the black test lead into COM, and the red test
lead into the A c input.

3. Using an ohmmeter, check the resistance between
the meter test leads. If the resistance is about 1 Ω,
the fuse is good. An open reading means that fuse
F2 is blown.

4. Move red test lead to .

W.

5. Using an ohmmeter, check the resistance between
the meter test leads. If the resistance is about 14 Ω,
the fuse is good. An open means that fuse F1 is
blown.

If a fuse is blown, replace it as follows. Refer to Figure 6
as necessary:

1. Remove the test leads from the meter and turn the
meter OFF.

2. With a standard blade hand screwdriver, turn each
battery door screw counterclockwise so that the slot
is parallel with the screw picture molded into the
case.

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

4. Replace the blown fuse(s).

5. Replace the battery access door. Secure the door by
turning the screws one-quarter turn clockwise.

33

789/787B

Users Manual

If the Meter does not Work

• Examine the case for physical damage. If there is
damage, make no further attempt to use the meter,
and contact a Fluke Service Center.

• Check the battery, fuses, and test leads.

• Review this manual to make sure you are using the

correct jacks and rotary function switch position.

If the meter still does not work, contact a Fluke Service
Center. If the meter is under warranty, it will be repaired
or replaced (at Fluke’s option) and returned at no charge.
See the Warranty on the back of the title page for terms. If
the warranty has lapsed, the meter will be repaired and
returned for a fixed fee. Contact a Fluke Service Center
for information and price.

Replacement Parts and Accessories

! Warning

To avoid personal injury or damage to the
meter, use only the specified replacement
fuse, 440 mA 1000 V fast-blow, Fluke
PN 943121.

Note

When servicing the meter, use only the
replacement parts specified here.

Replacement parts and some accessories are shown in
Figure 6 and listed in Table 13. Many more DMM
accessories are available from Fluke. For a catalog,
contact the nearest Fluke distributor.

To find out how to order parts or accessories use the
telephone numbers or addresses in How to Contact
Fluke.

34

ProcessMeter™

Replacement Parts and Accessories

1

2

9

18

19

24

25

26

13

14

15

16

2x

20

2x

W

2x

21

22

3

10

4x

4

5

11

12

28

29

27

2x

6

23

2x

7

8

17

3x

4x

anw038.eps

Figure 6. Replacement Parts

35

789/787B

Users Manual

Item

Number

Table 13. Replacement Parts

Description

Fluke PN

for 789

Fluke PN

for 787B

Quantity

 Knob Assembly with o-ring 658440 4772670 1
 Decal, Top Case 1623923 4772201 1
 Keypad 1622951 1
 Top Shield 4772681 1
 Top Shield Contact 674853 1
 LCD Display 1883431 1
 LCD Connectors, Elastomeric 1641965 2
 Backlight/Bracket 4756199 1
 Top Case with Lens Protector 1622855 4772197 1
 Contact Housing 1622913 1
 RSOB Contact 1567683 4
 Mask 1622881 4772655 1
  Fuse, 440 mA, 1000 V fast-blow 943121 2
 PCB Screw 832220 2
 Battery Contact, Negative 658382 1
 Battery Contact, Positive 666438 1
 Battery Contacts Dual 666435 3

36

ProcessMeter™

Replacement Parts and Accessories

Table 13. Replacement Parts (cont.)

Item

Number

Description

Fluke PN

for 789

Fluke PN

for 787B

Quantity

 Bottom Insulator 4811256 1
 Bottom Shield 1675171 1
 Shock Absorber 878983 1
 IR Lens 658697 1
 Bottom Case 659042 4772662 1
 Case Screws 1558745 4
 Battery, 1.5 V, 0-15 mA, AA Alkaline 376756 4
 Accessory Mount with Probe Holders 658424 1
 Shock Absorber 674850 1
 Access Door, Battery/Fuse 1622870 1
 Fasteners, Battery/Fuse Access Door 948609 2
 Tilt-Stand 659026 1

- Test Leads variable

- Alligator Clips variable

[1] See www.fluke.com for more information about the test leads and alligator clips available for your region.

[1]

1 (set of 2)

[1]

1 (set of 2)

37

789/787B

Users Manual

Specifications

All specifications apply from +18 °C to +28 °C unless
stated otherwise.

All specifications assume a 5-minute warm-up period.

The standard specification interval is 1 year.

Note

“Counts” refers to the number of increments or
decrements of the least significant digit.

DC Volts Measurement

Range (V dc) Resolution Accuracy, ±(% of Reading + Counts)

4.000 0.001 V 0.1 % + 1

40.00 0.01 V 0.1 % + 1

400.0 0.1 V 0.1 % + 1
1000 1 V 0.1 % + 1

Input impedance: 10 MΩ (nominal), < 100 pF
Normal mode rejection ratio: > 60 dB at 50 Hz or 60 Hz
Common mode rejection ratio: > 120 dB at dc, 50 Hz, or 60 Hz
Overvoltage protection: 1000 V

38

ProcessMeter™

Specifications

DC Millivolts Measurement

Range (mV dc) Resolution Accuracy, ±(% of Reading + Counts)

400.0 0.1 mV 0.1 % + 2

AC Volts Measurement

Range (ac) Resolution

400.0 mV 0.1 mV 0.7 % + 4 1.2 % + 4 7.0 % + 4

4.000 V 0.001 V 0.7 % + 2 1.2 % + 4 7.0 % + 4

40.00 V 0.01 V 0.7 % + 2 1.2 % + 4 7.0 % + 4

400.0 V 0.1 V 0.7 % + 2 1.2 % + 4 7.0 % + 4
1000 V 1 V 0.7 % + 2 1.2 % + 4 7.0 % + 4

Specifications are valid from 5 % to 100 % of amplitude range.
AC conversion: true rms
Maximum crest factor: 3 (between 50 and 60 Hz)
For non-sinusoidal waveforms, add
Input impedance: 10 M
Common mode rejection ratio: > 60 dB at dc, 50 Hz, or 60 Hz

Ω

(nominal), < 100 pF, ac-coupled

±

(2 % reading + 2 % f.s.) typical

50 Hz to 60 Hz 45 Hz to 200 Hz 200 Hz to 500 Hz

Accuracy, ±(% of Reading + Counts)

39

789/787B

Users Manual

AC Current Measurement

Range

45 Hz to 2 kHz

1.000 A (Note) 0.001 A 1 % + 2 1.5 V/A

Note: 440 mA continuous, 1 A 30 seconds maximum
Specifications are valid from 5 % to 100 % of amplitude range.

AC conversion: true rms
Maximum crest factor: 3 (between 50 and 60 Hz)
For non-sinusoidal waveforms, add
Overload protection 440 mA, 1000 V fast-blow fuse

Resolution Accuracy, ±(% of Reading + Counts)

±

( 2 % reading + 2 % f.s.) typical

Typical Burden

Voltage

DC Current Measurement

Range Resolution Accuracy, ±(% of Reading + Counts)

30.000 mA 0.001 mA 0.05 % + 2 14 mV/mA

1.000 A (Note) 0.001 A 0.2 % + 2 1.5 V/A

Note: 440 mA continuous, 1 A 30 seconds maximum
Overload protection: 440 mA, 1000 V fast-blow fuse

Typical Burden

Voltage

40

ProcessMeter™

Specifications

Ohms Measurement

Range Resolution Measurement Current Accuracy, ±(% of Reading + Counts)

400.0 Ω 0.1 Ω 310 μA 0.2 % + 2

4.000 kΩ 0.001 kΩ 31 μA 0.2 % + 1

40.00 kΩ 0.01 kΩ 2.5 μA 0.2 % + 1

400.0 kΩ 0.1 kΩ 250 nA 0.2 % + 1

4.000 MΩ 0.001 MΩ 250 nA 0.35 % + 3

40.00 MΩ 0.01 MΩ 125 nA 2.5 % + 3

Overload protection: 1000 V
Open circuit voltage: <3.9 V

41

789/787B

Users Manual

Frequency Counter Accuracy

Range Resolution Accuracy, ±(% of Reading + Counts)

199.99 Hz 0.01 Hz 0.005 % + 1

1999.9 Hz 0.1 Hz 0.005 % + 1

19.999 kHz 0.001 kHz 0.005 % + 1

Display updates 3 times/second at > 10 Hz

Frequency Counter Sensitivity

Minimum Sensitivity (rms Sinewave)

Input Range

AC

400 mV 150 mV (50 Hz to 5 kHz) 150 mV

4 V 1 V 1 V

40 V 4 V 4 V

400 V 40 V 40 V

5 Hz to 5 kHz*

(approximate trigger level 5 % of full scale)

DC

1000 V 400 V 400 V

*Usable 0.5 Hz to 20 kHz with reduced sensitivity.

6

10

VHz max

42

ProcessMeter™

Specifications

Diode Test and Continuity Test

Diode test indication ........................................... Displays voltage drop across device, 2.0 V full scale. Nominal test current 0.3 mA at

Continuity test indication ..................................... Continuous audible tone for test resistance <100 Ω

Open circuit voltage ............................................. 2.9 V

Short circuit current ............................................. 310 μA typical

Overload protection ............................................. 1000 V rms

Loop Power Supply Voltage ................................. 24 V, Short Circuit protected

DC Current Output

Source mode

Span .............................................................. 0 mA or 4 mA to 20 mA, with overrange to 24 mA

Accuracy........................................................ 0.05 % of span

Compliance voltage ....................................... 28 V with battery voltage >~4.5 V

Simulate Mode

Span .............................................................. 0 mA or 4 mA to 20 mA, with overrange to 24 mA

Accuracy........................................................ 0.05 % of span

Loop voltage .................................................. 24 V nominal, 48 V maximum, 15 V minimum

Compliance voltage ....................................... 21 V for 24 V supply

Burden voltage .............................................. <3 V

0.6 V. Accuracy ±(2 % + 1 count).

43

789/787B

Users Manual

General Specifications

Maximum Voltage between

any Terminal and Earth Ground ........................... 1000 V

Fuse Protection for

mA inputs ............................................................... 0.44 A, 1000 V, IR 10 kA

Power

Battery Type ........................................................ IEC LR6 (AA Alkaline)

Quantity ............................................................... 4

Temperature

Operating ............................................................ -20 °C to +55 °C

Storage ................................................................ -40 °C to +60 °C

Altitude

Operating ............................................................ ≤2000 m

Storage ................................................................ ≤12 000 m

Frequency Overload Protection ........................... 10

Temperature coefficient

Measurements .................................................... 0.05 x specified accuracy per °C for temperatures <18 °C or >28 °C

Source ................................................................. 0.1 x specified accuracy per °C for temperatures <18 °C or >28 °C

Relative humidity ................................................... 95 % up to 30 °C, 75 % up to 40 °C, 45 % up to 50 °C, and 35 % up to 55 °C

Size ......................................................................... 10.0 cm X 20.3 cm X 5.0 cm (3.94 in X 8.00 in X 1.97 in)

Weight .................................................................... 610 g (1.6 lb)

Safety

General ............................................................... IEC 61010-1: Pollution Degree 2

Measurement ...................................................... IEC 61010-2-033: CAT IV 600 V / CAT III 1000 V

6

V Hz max

44

ProcessMeter™

Specifications

Electromagnetic Compatibility (EMC) ................. Accuracy for all ProcessMeter functions is not specified in RF field >3 V/m

International ......................................................... IEC 61326-1: Portable Electromagnetic Environment; IEC 61326-2-2

CISPR 11: Group 1, Class A

Group 1: Equipment has intentionally generated and/or uses conductively-coupled
radio frequency energy that is necessary for the internal function of the equipment itself.

Class A: Equipment is suitable for use in all establishments other than domestic and
those directly connected to a low-voltage power supply network that supplies buildings
used for domestic purposes. There may be potential difficulties in ensuring
electromagnetic compatibility in other environments due to conducted and radiated
disturbances.

Caution: This equipment is not intended for use in residential environments and may
not provide adequate protection to radio reception in such environments.

Emissions that exceed the levels required by CISPR 11 can occur when the equipment
is connected to a test object.

Korea (KCC) ........................................................ Class A Equipment (Industrial Broadcasting & Communication Equipment)

Class A: Equipment meets requirements for industrial electromagnetic wave equipment
and the seller or user should take notice of it. This equipment is intended for use in
business environments and not to be used in homes.

USA (FCC) .......................................................... 47 CFR 15 subpart B. This product is considered an exempt device per clause 15.103.

45

789/787B

Users Manual

46