FLUKE 787B Process Meter Digital Multimeter And Loop Calibrator User Manual

787B Process Meter Digital Multimeter And Loop Calibrator

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Product Information

Specifications:

• Model: 789/787B ProcessMeterTM

• Release Date: August 2002, Rev. 4

• Type: Handheld, battery-operated

• Function: Measures electrical parameters and supplies steady or
  ramping current to test process instruments

• Additional Feature (789 model): 24 V loop power supply

Product Usage Instructions

Introduction

The Fluke 789/787B ProcessMeter is a versatile tool that
combines the functionality of a digital multimeter with current
output capability. It is designed for measuring electrical
parameters and providing power to test process instruments.

Safety Information

Before using the meter, ensure you read the safety information
provided in the manual. Pay attention to warnings and cautions to
prevent accidents or damage to the product or equipment under
test.

How to Contact Fluke

If you need assistance or information about the product, contact
Fluke using the provided telephone numbers. You can also register
your product or access the latest manual supplement online.

Battery Life

Monitor the battery indicator on the meter and replace the
battery promptly to avoid false readings that could lead to safety
hazards. Refer to Table 12 for typical alkaline battery life and
follow the guidelines to preserve battery longevity.

Maintenance

Basic maintenance of the Fluke 789/787B ProcessMeter includes
cleaning the case with a damp cloth and detergent. Avoid using
abrasive materials or solvents that could damage the device. For
any repairs, calibration, or servicing, consult qualified personnel
or a Fluke Service Center.

FAQ

Q: What should I do if the meter is damaged or missing

parts?

A: Contact the place of purchase immediately for assistance. For
replacement parts or accessories, refer to Table 13 in the manual
or contact a Fluke distributor.

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789/787B ProcessMeterTM

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.

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 authorized 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 consequential damages, this limitation of liability may not apply to you.

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

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

11/99

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

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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.

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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: +31 402-675-200 · Japan: +81-3-6714-3114 · Singapore: +65-6799-5566 · Anywhere in the world: +1-425-446-5500 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

· 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.

ProcessMeterTM Safety Information
· 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.

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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

ProcessMeterTM Safety Information

Symbol

Table 1. International Symbols

Description

Symbol

Description

WARNING. RISK OF DANGER. Consult user documentation. Conforms to European Union directives

WARNING. HAZARDOUS VOLTAGE. Risk

of electric shock.

Conforms to relevant South Korean EMC Standards

Minimum fuse interrupt rating.

Certified by CSA Group to North American safety standards. AC (Alternating Current)
DC (Direct Current)
Battery

Conforms to relevant Australian Safety and EMC standards. Earth
Fuse
Double Insulated

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.

5

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

Table 2. 789/787B ProcessMeter
1 3
0%
2
4

ProcessMeterTM Getting Acquainted with the Meter
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.

Item

Description Display Rotary switch Pushbuttons Input/Output jacks

anw014f.eps

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789/787B Users Manual

Table 3. Input/Output Jacks

1

A

mA

COM

V

3

Item

Jack A c mA d
V
COM

2
Measurement Functions
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, , continuity, and diode test.
Common for all measurements.

4 Source Current Function

anw001f.eps
Simulate Transmitter Function

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

Common for dc current output Output for transmitter simulation to

to 24 mA. Common for loop 24 mA. (Use in series with an

power supply.

external loop supply.)

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

8

ProcessMeterTM Getting Acquainted with the Meter

Table 4. Rotary Function Switch Positions for Measurements

4

5

3

6

2

1

No. Position

Function(s)

OFF

Meter off

Default:

Measure ac V

S

h

Frequency counter

Pushbutton Actions

anw002f.eps

M Selects a MIN, MAX, or AVG action R Selects a fixed range (hold 1 second for auto range) H Toggles AutoHold r Toggles relative reading (sets a relative zero point)

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789/787B Users Manual

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

No. Position

Function(s)

Pushbutton Actions

Default:

T

Measure dc V
h

Frequency counter

Default:

Measure dc mV

U h

Frequency counter

Same as above Same as above (mV has only one range)

Default: Measure

V

G for continuity

J (Blue) D test

Same as above (diode test has only one range)

High test lead in cA: Measure Same as above (only one range for each input jack position,

A dc

30 mA or 1 A)

W

J (Blue) selects ac

High test lead in dmA:

Measure mA dc

10

ProcessMeterTM Getting Acquainted with the Meter
Table 5. Rotary Function Switch Positions for mA Output

1

No. Position

Default Function

Test leads in

SOURCE:

OUTPUT X

Source 0 % mA

Test leads in SIMULATE:

Sink 0 % mA

2
3
anw008f.eps
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 %

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789/787B Users Manual

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

No. Position

Default Function

Test leads in

SOURCE:

Source repeating

OUTPUT 0 % -100 %-0 %

Y

slow ramp (m)

monp Test leads in SIMULATE:

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

mA

250 HART

Test leads in SOURCE:

LOOP POWER Supply 24 V loop power,

(789 only) measure mA

Pushbutton Actions 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 series resistor for HART communication switched in · 250 series resistor switched out

12

ProcessMeterTM Getting Acquainted with the Meter

Table 6. Pushbuttons

No. Pushbutton

Function

4 3

K

Set the backlight to low, high, and off

5

6

Span Check mA Output: Adjusts mA output to 0 %

value (4 mA or 0 mA)

100%

MIN MAX

RANGE

HOLD

0%

REL

Hz

mA Output: Sets mA output to 100 %

Span Check value (20 mA)

2 1

10

9

7

8
anw003f.eps

M
% STEP

R

Measuring: Selects a MIN, MAX, or AVG action
mA Output: Adjusts mA output up to the next higher 25 % step
Measuring: Selects a fixed range (hold for 1 second for auto range)

COARSE mA Output: Adjusts output up 0.1 mA

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789/787B Users Manual

No.

14

Pushbutton
H
FINE FINE
h

J (BLUE) (alternate function)
COARSE
r
% STEP
G

Table 6. Pushbuttons (cont.)
Function 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
W Rotary function switch in position and test lead plugged into Ac jack: Toggles between
ac and dc ampere measure Rotary function switch in V position: Toggles diode test function (D) 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 series resistor Measuring: Toggles relative reading (sets a relative zero point) mA Output: Adjusts output down 0.1 mA
Measuring: Toggles between measure and continuity functions mA Output: Adjusts mA output down to the next lower 25 % step

ProcessMeterTM Getting Acquainted with the Meter

Table 7. Display

89

11

12

7

10

6

5 13
4

3

14

15

2

1

17

16

anw004f.eps

No.

Element

Meaning

% (Percentage display) 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)

OUTPUT

Lights when mA output (source or simulate) is active

S

Lights in continuity function

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789/787B Users Manual

No.

Element

b
q Numerals lI
D I N MAX MINAVG
MkkHzmAV ACDC

Table 7. Display (cont.)
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

ProcessMeterTM Getting Acquainted with the Meter

Table 7. Display (cont.)

No.

Element

Meaning

Auto Range

Range status indicators:

Manual Range

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

400100030

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

mV

mo np

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)

250 HART

Lights when 250 series resistance is switched in (789 only)

Loop Power

Lights when in loop supply mode (789 only)

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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 M. 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.
18

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.
V 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.

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.

ProcessMeterTM Measuring Electrical Parameters
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.

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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 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

789 PROCESSMETER

100%

MIN MAX

RANGE

HOLD

0%

REL

Hz

ProcessMeterTM Using the Current Output Functions

40 20

60 80

0

100

Figure 1. Sourcing Current

anw010f.eps
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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

dc V Power Supply
COM +24V

789 PROCESSMETER

100%

MIN MAX

RANGE

HOLD

0%

REL

Hz

ProcessMeterTM Using the Current Output Functions

40 20

60 80

0

100

Figure 2. Simulating a Transmitter

anw011f.eps
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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
X
R
COARSE X
M
FINE
FINE
h
W
COARSE
r
W

Adjustment Adjusts up 0.1 mA Adjusts up 0.001 mA Adjusts down 0.001 mA
Adjusts down 0.1 mA

24

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.

ProcessMeterTM Using the Current Output Functions

Table 9. mA Stepping Pushbuttons

Pushbutton
X
M
% STEP
% STEP
G
W

Span Check
Span Check

Adjustment Adjusts up to the next higher 25 % step
Adjusts down to the next lower 25 % step
Sets to 100 % value
Sets to 0 % value

Step 0 % 25 % 50 % 75 % 100 % 120 % 125 %

Table 10. mA Step Values

Value (for each span setting)

4 to 20 mA

0 to 20 mA

4.000 mA

0.000 mA

8.000 mA

5.000 mA

12.000 mA

10.000 mA

16.000 mA

15.000 mA

20.000 mA

20.000 mA

24.000 mA

24.000 mA

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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

ProcessMeterTM Power-Up Options

Table 11. Power-Up Options

Option Current Span

Button

Switch Position

R All

Backlight Timeout

K

All

Beeper Auto Power-Off
Note: Auto power-off is always disabled when MIN MAX recording is on.
LCD segments

G J (Blue)
H

All
All
VAC, mA, Source, Ramp, Loop

Firmware version

H VDC

Model number

H

Go to Calibration mode H

mVDC

Default

Display

Action Taken

Retains setting Retains setting Retains setting

– or – / /

Toggles between 0-20 mA and 4-20 mA range
Enables/Disables the auto-off on backlight after 2 minutes
Enables/Disables beeper

Enabled

Disables the feature that turns off the power after 30 minutes of inactivity.

Disabled
Disabled Disabled Disabled

All segments
ex: ex:

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) Calibration mode starts

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789/787B 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 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.

Voltage (V)

32

30

28

26

24

22

20

0

4

8

12

16

20

24

Current (mA)

Loop Voltage w/o 250

Loop Voltage w/ 250

anw020f.eps
Figure 3. Loop Power Voltage vs. Current

28

789 PROCESSMETER

100%

MIN MAX

RANGE

HOLD

0%

REL

Hz

ProcessMeterTM Loop Power Supply Mode (789 only)
TEST DC PWR
­ ++ ­ + ­

Figure 4. Connections for Supplying Loop Power

anw009f.eps
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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 Measuring any parameter Simulating Current Sourcing 12 mA into 500

Hours 140 140 10

30

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.

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.

ProcessMeterTM Maintenance
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.

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789/787B Users Manual

F2

F1

Figure 5. Replacing the Batteries and Fuses

anw037.eps

32

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:
W 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 , the fuse is good. An open reading means that fuse F2 is blown.
4. Move red test lead to .

ProcessMeterTM Maintenance
5. Using an ohmmeter, check the resistance between the meter test leads. If the resistance is about 14 , 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.

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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

1 2
3
4 5 6 7 2x 8

9

13 2x

10

W

11 4x

2x
14

15

12

16

ProcessMeterTM Replacement Parts and Accessories
24
18 25
19 26 27
2x 20 228x

21

29

22

4x 23

17 3x
Figure 6. Replacement Parts

anw038.eps
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789/787B Users Manual

Item Number

Table 13. Replacement Parts

Description

Fluke PN for 789

Fluke PN for 787B

Knob Assembly with o-ring

658440

4772670

Decal, Top Case

1623923

4772201

Keypad

1622951

Top Shield

4772681

Top Shield Contact

674853

LCD Display

1883431

LCD Connectors, Elastomeric

1641965

Backlight/Bracket

4756199

Top Case with Lens Protector

1622855

4772197

Contact Housing

1622913

RSOB Contact

1567683

Mask

1622881

4772655

Fuse, 440 mA, 1000 V fast-blow

943121

PCB Screw

832220

Battery Contact, Negative

658382

Battery Contact, Positive

666438

Battery Contacts Dual

666435

Quantity
1 1 1 1 1 1 2 1 1 1 4 1 2 2 1 1 3

36

ProcessMeterTM Replacement Parts and Accessories

Table 13. Replacement Parts (cont.)

Item Number

–
–

Description
Bottom Insulator Bottom Shield Shock Absorber IR Lens Bottom Case Case Screws Battery, 1.5 V, 0-15 mA, AA Alkaline Accessory Mount with Probe Holders Shock Absorber Access Door, Battery/Fuse Fasteners, Battery/Fuse Access Door Tilt- Stand Test Leads Alligator Clips

Fluke PN for 789

Fluke PN for 787B

4811256

1675171

878983

658697

659042

4772662

1558745

376756

658424

674850

1622870

948609

659026 variable[1] variable[1] [1] See www.fluke.com for more information about the test leads and alligator clips available for your region.

Quantity
1 1 1 1 1 4 4 1 1 1 2 1 1 (set of 2) 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

4.000

0.001 V

40.00

0.01 V

400.0

0.1 V

1000

1 V

Input impedance: 10 M (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

Accuracy, ±(% of Reading + Counts) 0.1 % + 1 0.1 % + 1 0.1 % + 1 0.1 % + 1

38

ProcessMeterTM Specifications

DC Millivolts Measurement

Range (mV dc)

Resolution

400.0

0.1 mV

Accuracy, ±(% of Reading + Counts) 0.1 % + 2

AC Volts Measurement

Range (ac)

Resolution

Accuracy, ±(% of Reading + Counts)

50 Hz to 60 Hz

45 Hz to 200 Hz

200 Hz to 500 Hz

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 ±(2 % reading + 2 % f.s.) typical Input impedance: 10 M (nominal), < 100 pF, ac-coupled Common mode rejection ratio: > 60 dB at dc, 50 Hz, or 60 Hz

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789/787B Users Manual

AC Current Measurement

Range 45 Hz to 2 kHz

Resolution

Accuracy, ±(% of Reading + Counts)

1.000 A (Note)

0.001 A

1 % + 2

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 ±( 2 % reading + 2 % f.s.) typical Overload protection 440 mA, 1000 V fast-blow fuse

DC Current Measurement

Range

Resolution

Accuracy, ±(% of Reading + Counts)

30.000 mA

0.001 mA

1.000 A (Note)

0.001 A

Note: 440 mA continuous, 1 A 30 seconds maximum

Overload protection: 440 mA, 1000 V fast-blow fuse

0.05 % + 2 0.2 % + 2

Typical Burden Voltage 1.5 V/A
Typical Burden Voltage 14 mV/mA 1.5 V/A

40

Ohms Measurement

Range

Resolution

400.0

0.1

4.000 k

0.001 k

40.00 k

0.01 k

400.0 k

0.1 k

4.000 M

0.001 M

40.00 M

0.01 M

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

Measurement Current 310 µA 31 µA 2.5 µA 250 nA 250 nA 125 nA

ProcessMeterTM Specifications
Accuracy, ±(% of Reading + Counts) 0.2 % + 2 0.2 % + 1 0.2 % + 1 0.2 % + 1 0.35 % + 3 2.5 % + 3

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789/787B Users Manual

Frequency Counter Accuracy

Range

Resolution

199.99 Hz

0.01 Hz

1999.9 Hz

0.1 Hz

19.999 kHz

0.001 kHz

Display updates 3 times/second at > 10 Hz

Accuracy, ±(% of Reading + Counts) 0.005 % + 1 0.005 % + 1 0.005 % + 1

Frequency Counter Sensitivity

Input Range

Minimum Sensitivity (rms Sinewave)

5 Hz to 5 kHz*

DC

AC

(approximate trigger level 5 % of full scale)

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

1000 V

400 V

*Usable 0.5 Hz to 20 kHz with reduced sensitivity. 106 VHz max

400 V

42

ProcessMeterTM 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 0.6 V. Accuracy ±(2 % + 1 count). Continuity test indication ……………………………….Continuous audible tone for test resistance <100 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
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 ……………………… 106 V Hz max 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
44

ProcessMeterTM 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

References

• Fluke Corporation: Fluke Electronics, Calibration and Networks

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