Fluke 8010A User manual

.14

PN 834192
August 1988 Rev. 5, 1/93
©1993 John Fluke Mfg. Co., Inc. All rights reserved. LHho in U.S.A
TRUE RMS MULTIMETER
USER'S MANUAL
FLUKE

NOTICE
The Fluke 87 generates and uses radio frequency energy. If it is not used according to the
Instructions in this manual, it may cause interference to radio and television reception. The
Fluke 87 has been type tested and found to comply with the limits for aclass Bcomputing
device in accordance with the specifications in Subpart Jof Part 15 of FCC rules, which are
designed to provide reasonable protection against such interfence in aresidential location.
However, there Is no guarantee that interference will not occur in aparticular location. If this
equipment does cause Interference, which can be determined by turning the Fluke 87 off and
on, the user is encouraged to try to correct the interference by one or more of the following
measures:
•Move the Fluke 87 away from the receiver.
•If necessary, the user should consult the dealer or an experienced radio/television
technician for additional suggestions.

CONTENTS
TITLE PAGE
INTRODUCTION 1
MULTIMETER SAFETY 2
GETTING STARTED QUICKLY 3
HOW TO USE THE METER 4
Input Terminals and Input Alert 6
Function Selector Rotary Switch 6
Pushbuttons 8
Summary of Power-on Options 12
Digital and Analog Displays 13
Holster and Flex-Stand 17
APPLICATIONS 17
Measuring Voltage (AC/DC) 17
Measuring Current 17
Continuity Testing 19
Measuring Resistance 19
Using Conductance for High Resistance or Leakage Tests 20
Noisy Resistance Measurements 21
/(continued on page ii)

CONTENTS, continued
TITLE PAGE
Measuring Capacitance 21
Diode Testing 22
Using the Analog Bar Graph 23
Using the MIN MAX Recording Mode 23
Measuring Frequency 24
Measuring Duty Cycle 26
Pulse Width Measurements 27
MAINTENANCE 28
General Maintenance 28
Calibration 28
Battery Replacement 28
Fuse Test 30
Fuse Replacement 30
Service 31
REPLACEMENT PARTS 32
SPECIFICATIONS 34
SERVICE CENTERS 42
/'/'

INTRODUCTION
INTRODUCTION
NOTE
This meter has been designedand tested according to
IEC Publication 348, Safety Requirementsfor Elec-
tronic Measuring Apparatus. This manual contains
information and warnings which must befollowed
to ensure safe operation and retain the meter in safe
condition.
WARNING
READ "MULTIMETER SAFETY" BEFORE
USING THE METER.
The Fluke 87 True RMS Multimeter (also referred to as "the
meter") is ahandheld, 4000-count instrument that is designed
for use in the field, laboratory, and at home. The meter com-
bines the precision of adigital meter with the speed and versa-
tility of ahigh resolution analog display. Frequencies between
0.5 Hz and 200 kHz can be measured with up to 0.01 Hz resolu-
tion. The meter is powered by a9V battery and has arugged
case sealed against dirt, dust and moisture. Asnap-on holster,
with flexible stand (Flex-Stand™), protects the meter from
rough handling. The flexible stand allows the meterto be stood
or hung.
The meter also provides:
•AMIN MAX Recording mode, in which the meter
"remembers" the lowest and highest readings, calcu-
lates the true average of all readings taken over a
period as long as thirty-six hours, and displays these
values. The beeper emits aMin Max Alert™ when a
new minimum or maximum reading is recorded.
•APeak MIN MAX mode that captures changes as short
as 1millisecond.
•An alternate Frequency Counter mode that measures
duty cycle and displays it as avalue between 0.0 and
99.9%.
•An Input Alert™ that causes the beeper to sound if the
test leads are plugged into the wrong input terminals for
the function being performed.
•AREL mode that allows you to store areading in
memory, and display the difference between the stored
value and subsequent readings.
•ATouch Hold® mode that allows you to keep your eyes
fixed on the probes when taking measurements in diffi-
cult or hazardous circumstances, then read the display
when it is convenient and safe.
"Input Alert, Flex-Stand, and MIN MAX Alert are trademarks of the John Fluke Mfg. Co., Inc. 1

MULTIMETER SAFETY
•Adisplay back-light that makes the meter useable in
dark areas.
•A41/2-digit display mode for ten times increase in
resolution.
•ACapacitance mode that measures capacitors from
0.01 nFto5//F.
After unpacking the meter, if you notice that the meter is dam-
aged or something is missing, contact the place of purchase
immediately. Save the shipping container and packing mate-
rial in case you have to reship the meter.
MULTIMETER SAFETY
Before usings the meter, read the following safety information
carefully. Inthis manualtheword, "WARNING," is reserved for
conditions and actions that pose hazard(s) to the user; the
word, "CAUTION," is reserved for conditions and actions that
may damage your meter. The symbols shown in Figure 1are
used internationally to denote the electrical functions and
conditions indicated. If the meter is not used as described in
this manual, the safety features of the meter might be impaired.
•Avoid working alone.
•Do not allow the meter to be used if it is damaged, or its
safety is impaired.
2
Inspect the test leads for damaged insulation or exposed
metal. Check test lead continuity. Damaged leads should
be replaced.
Be sure the meter is in good operating condition. During
acontinuity test, a meter reading that goes from over-
load (OL) to generally means the meter is working
properly.
Select the proper function and range for your
measurement
WARNING
TO AVOID ELECTRICAL SHOCK, USE CAUTION
WHEN WORKING ABOVE 60V DC OR 25V AC
RMS. SUCH VOLTAGES POSE ASHOCK
HAZARD.
HDANGEROUS
VOLTAGE _L GROUND
AC -ALTERNATING
CURRENT ASEE EXPLANATION IN MANUAL
DC -
DIRECT CURRENT PI DOUBLE INSULATION
(Protection Class II)
EITHER
DC OR AC FUSE
Figure 1. International Electrical Symbols

•Disconnect the live test lead before disconnecting the
common test lead.
•Follow all safety procedures for equipment being tested.
Disconnect the input power and discharge all high-
voltage capacitors through aprotective impedance
before testing in the Oand -w- functions.
•When making acurrent measurement turn the power
off before connecting the meter in the circuit.
•Check meter fuses before measuring current trans-
former secondary or motor winding current (See "Fuse
Test" in the "MAINTENANCE" Section.) An open fuse
may allow high voltage build-up, which is potentially
hazardous.
GETTING STARTED QUICKLY
Examine the meter carefully, familiarizing yourself with the
layout of the input terminals, rotary switch, pushbuttons and
display. Notice the WARNING information and summary of
power-on options engraved into the rear panel.
If you have used amultimeter before, simply examining your
meter will probably give you agood idea how to use it. The
following procedure is an overview of how to take basic
measurements.
GETTING STARTED QUICKLY
WARNING
TO AVOID ELECTRICAL SHOCK OR DAMAGE
TO THE METER, DO NOT APPLY MORE THAN
1000V BETWEEN ANY TERMINAL AND EARTH
GROUND.
1. Insert the test leads in the appropriate input terminals
(see Table 1). If the test leads are in the wrong input ter-
minals when the meter is turned on and the beeper has
not been disabled, the beeper will emit awarning. See
"Input Terminals and Input Alert", below.
2. To turn the meter on and select afunction, turn the rotary
switch from OFF to the appropriate switch position. All
segments on the liquid -crystal display (LCD) will turn on
for one second, then the meter is ready for normal oper-
ation. If you would like to freeze the display with all seg-
ments on, press and hold down any button, while turning
the meter on. As long as the button is held down, all LCD
segments will remain on.
3. To select an additional operation, press the appropriate
pushbuttons above the rotary switch as described in the
items below. (See also, Figure 2.)
3

HOW TO USE THE METER
•To operate the MIN MAX and RANGE buttons: press to
select, press again to scroll or increment, and press and
hold for two seconds to exit.
•To operate the Hz button: press to select the frequency
mode, press again to select duty cycle, and press again
to exit.
•To operate the back-lit display, press the YELLOW but-
ton. The back-light automatically turns off in 68 seconds
to conserve battery life.
•To operate the remaining buttons: press to select and
press again to exit.
NOTE
The response of the display and the pushbuttons
slows down in the capacitance mode.
An annunciator is displayed when amode has been selected.
Aquick way to reset all the pushbuttons to their default state is
to turn the rotary switch to an adjacent function and then back
to the function you are using.
4. To take ameasurement, use the test lead probes to make
the proper contacts. Remember, insert the meter in the
circuit in parallel for voltage and in series for current
4
measurements. Read the measurement on the display. If
you did not manually select arange (by using the
RANGE button), the rangethat provides the best resolu-
tion is automatically selected.
5. To run aperformance check of the meter, turn the
rotary switch to Qarid connect atest lead from the
VO-w-input to the mA //A input. (If you are using atest
probe, touch the half of the input contact nearest the
LCD.) The display should read 1.000 kQ ±5digits. With
the rotary switch still at Q, test the Afuse (15A) by
inserting the plug end of the test lead into the Ainput
and test the mA //A fuse (1 A) by inserting the plug end
of the test lead into the mA fjA input. The beeper emits
an Input Alert if the fuses are good.
Although this procedure will allow you to get started quickly,
we suggest that you take the time to read the remainder of this
manual so that you can learn to take full advantage of your
meter's capabilities.
HOW TO USE THE METER
This section describes your meter and how to use it. FOR
EASEOFREFERENCE, EACH DESCRIPTIONIS NUMBERED
AND KEYED TO THE ILLUSTRATION INSIDE THE FRONT
COVER.

HOW TO USE THE METER
Input Terminals
Table 1.Input Terminals and Limits
FUNCTION INPUT TERMINALS
Red Lead Black Lead
MIN DISPLAY
READING MAX DISPLAY
READING MAXIMUM
INPUT
vCOM 0.1 mV 1000V 1000V
"if
wvn-**- COM 0001V 1000V 1000V
mV vn -H- COM 0.01 mV 400.0 mV 1000V
n
nS
H(-
vn-«-
vn-*-
vn-*-
COM
COM
COM
0.01 n
0.001 nS
0.01 nF
40.00 Mn
40.00 nS
5.00 fjF
1000V
t
1000V
t
1000V
t
-w- vn-**- COM 0.0001V 3.000V 1000V
t
AACOM 1mA 20.00A* 15A600V FAST Fuse**
mA —
/iA~ mA/AiA
mA//iA COM
COM 0.01 mA 0.1 fjt\
400.0 mA
4000 /jA 1A 600V FAST Fuse**
*10A continuous, 20A for 30 seconds maximum. **Fuse protected. fFor circuits <0.3A short circuit, 660V for high energy circuits.
5

HOW TO USE THE METER
Input Terminals and Function Selector Rotary Switch
Input Terminals and Input Alert
Items 1-4 describe the input terminals. (See Table 1for
overload limits.) If the test leads are connected to the
Amperes input terminal, and the function selector switch is
not in the Amp measurement position, the beeper will emit an
Input Alert. An Input Alert will also sound if the test leads are
connected to the mAyuA terminal and the function switch is
not in either Amp position. After an Input Alert sounds, the
meter will attempt to take areading from inputs applied to the
VQ-H- terminal. Input Alert can be disabled by pressing
("Hi )while turning the rotary switch from OFF to any
function position.
AAmperes Input Terminal
For current measurements (ac ordc) up to 10Acon-
tinuous (20A for 30 seconds) when function selec-
tor switch set to mA .
mA fjA Milliamp/Microamp Input Terminal
For current measurements up to 400 mA (ac or dc)
when the function selector switch is set to mA ~or
A
6
COM Common Terminal
Return terminal for all measurements.
VC1 -M- Volt, Ohms, Diode Test Input Terminal
Function Selector Rotary Switch
(5) Item 5describes functions that are selected by
setting the rotary switch. Each time the rotary
switch is moved from OFF to afunction setting, all
LCD segments will turn on for one second as part of
aselftest routine. (This selftest routine is also per-
formed if the rotary switch is turned slowly from one
position to another.) The meter is then ready for
normal operations and will respond to the rotary
switch and pushbuttons.
OFF
Power to the meter is turned off.
\f Volts ac
Autoranges to the 400 mV, 4V, 40V, 400V or 1000V
range.

VVolts dc
Autoranges to the 4V, 40V, 400V or 1000V range.
mV Millivolts dc
Single 400 mV range.
ml) -#- Resistance (O), conductance (1/0),
capacitance or continuity »m
testing
Press BLUE button to toggle between the resist-
ance and capacitance function. (The response of
the display and the pushbuttons slows down in the
capacitance mode.)
Autoranges to the 400O, 4kO, 40 kO, 400 kO, 4MO,
or 40 MO resistance range.
In Manual Ranging mode, 40 nS conductance
range (equal to a25-100,000 MO range) is select-
able. (See item 9.)
Autoranges to the 05.00 nF, .0500 fjF, 0.500 fjF, and
05.00 /jF capacitance range.
HOW TO USE THE METER
Function Selector Rotary Switch
When testing continuity, the beeper sounds if the
resistance falls below the typical values indicated
in Table 2.
Table 2. Beeper Responses in Continuity Test
Input Range Beeper On If
400.00 <40O
4.000 kO <200O
40.00 kO <2kO
400.0 kO <20 kO
4.000 MO <200 kO
40.00 MO <200 kO
Diode Test
Measures forward voltage of semiconductor junc-
tion® at approximately 1mA test current. Single
0-3V range.
m
£S3 Milliamps or amperes
Defaults to dc. Press BLUE button to toggle between
dc and ac.
Autoranges to the 40 mA or 400 mA range when
using the mAj/A input terminal, orto the 4000 mA
or 10A range when using the Ainput terminal.

HOW TO USE THE METER
Pushbuttons
fjA ^Microamps.
Defaults to dc. Press BLUE button to toggle between
dc and ac.
Autoranges to the 400 //A or 4000 fjA range when
using the mA yuA input terminal.
Pushbuttons
Items 6-13 describe how to use the pushbuttons. These but-
tons are used (in conjunction with rotary switch) to select
operating modes and set power-on options. When abutton is
pushed the beeper sounds (unless the beeper has been
turned off or the Data Output mode has been selected). A
summary of pushbutton operations is shown in Figure 2. An
annunciator is displayed to indicate that amode or option has
been selected. Aquick way to reset all the pushbuttonsto their
default state is to turn the rotary switch to an adjacent function
and then back to the function you are using.
(?) QDisplay Back-Light
Press the YELLOW button to turn on the back-light.
Back-light turns off automatically after 68 seconds
to extend battery life.
Power-On Option: 4Vs-Digrl Display Mode
The meter displays the readings at 10 times the resolution with a
maximum display at 19,999 counts. The display is updated once
per second. The 4-% digit display mode works in all (unctions
except capacitance, Peak MIN MAX and 100 millisecond MIN
MAX.
8
AC or DC, Resistance or Capacitance
Press BLUE button to toggle between ac and dc
when measuring current, or between capacitance
and resistance when the rotary switch is set to
mil nHi-.
Power-On Option: Disable Automatic Power-off
Automatic Power-off extends the life of the battery by turning the
meter off If neither the rotary switch nor apushbutton is operated
for half an hour. (Automatic Power-off is not allowed in the MIN
MAX Recording or Data Output modes.) The meter turns back on if
either the rotary switch is turned or apushbutton is pressed.
Qjiin max) Minimum (MIN), Maximum (MAX),
Average (AVG) Recording
Press (uinuax) to enter the MIN MAX Recording
mode (manual range only). Select the proper
range before selecting MIN MAX to ensure that
themin max reading will not exceed the measure-
ment range. The minimum, maximum, and average
values are then reset to the present input; the
RECORD annunciator turns on;theAUTOannuncia-
tor turns off; and the automatic power-off feature
is disabled.
In the MIN MAX Recording mode, the minimum
and maximum readings are stored in memory. The
beeper emits atone when anew minimum or
maximum value is recorded. Acontinuous beeper

HOW TO USE THE METER
Pushbuttons
—PRESS TO SELECT
—PRESS TO TURN ON BACK LIGHT
—TURNS OFF AUTOMATICALLY AFTER 68 SECONDS
Figure 2. Summary of Pushbutton Operations
9

HOW TO USE THE METER
Pushbuttons
tone is emitted when an overload is recorded.
Push (uinuax) to cycle through the maximum
(MAX), minimum (MIN), average (AVG), and present
readings. The MIN, MAX, or AVG annunciator
turns on to indicate what value is being displayed.
If an overload is recorded, the averaging function
is stopped and the average value becomes OL
(overload).
The true average of all the readings taken over at
least athirty-six hour period can be displayed. If
this duration is exceeded, the actual minimum and
maximum readings will continue to be captured
and can be displayed. However, new averages are
no longer calculated. The last average calculated
is retained as the average reading.
At normal (default) record speed, changes to the
voltage, current, or resistance inputs that last at
least 100 milliseconds are recorded, and the "100
ms" annunciatorturns on. Press and hold down the
(miwm»x) for 2seconds to exit and erase recorded
readings.
In the MIN MAX mode, press C"'» )to select the
Peak MIN MAX mode ("1 ms", "RECORD", and
"MAX" are displayed). Voltage or current inputs that
last for 1milliseconds or longer are captured. Press
10
(uinuax) to select the minimum (MIN) reading. Press
again to return to the maximum (MAX)reading. To
reset the Peak MIN MAX mode press (~^iT) twice:
the first press exits the mode, and the second press
re-enters the mode. To completely exit the MIN
MAX mode, press (WW) for one second. In Peak
MIN MAX mode, the present reading, average
(AVG) readings, and analog display are not dis-
played. Before selecting Peak MIN MAX, select DC
voltage or current to DCcouple the input waveform;
or AC voltage to capacitively couple the input wave-
form. Peak MIN MAX works in all functions except
ohms, frequency and capacitance.
In the MIN MAX Recording mode, press to
stop the recording of readings; press again to res-
tart recording. If recording is stopped, the minimum,
maximum, average, and present values are frozen,
but the analog display continues to be active. When
recording is stopped, the stored readings are not
erased and you can still scroll through these
readings.
Power-On Option: Select High Accuracy MIN MAX Recording
The High Accuracy MIN MAX Recording mode has aresponse
time of approximately 1second. Changes of more than 1second
duration are recorded. The "1s" annunciator is turned on. In the
Frequency Counter mode, readings are always recorded at the
high accuracy recording speed; the response time is not selectable.

range jManual Ranging
press C^aQ to select the Manual Range mode
and turn off the AUTO annunciator. {The meter
remains in the range it was in when manual ranging
was selected.)
In the Manual Range mode, each time you press
(range )button, the range (and the input range
annunciator) increments, and anew value is dis-
played. If you are already in the highest range, the
meter "wraps around" to the lowest range.(In the
Frequency Counter mode, pressing (range") manu-
ally selects the input voltage or current range.) To
exit the Manual Range mode and return to auto-
ranging, Press and hold down (mhgP
)for 2seconds.
The AUTO annunciator turns back on.
When the range is changed manually, the Touch
Hold, MIN MAX Recording, and REL[ative] modes
are disabled.
Power-On Option; Rolary Switch Teat
The Rotary Switch Test is used only for servicing purposes. See
the SO Series Service Manual for details. In the Rotary Switch Test
mode, normal meter functions are disabled. To exit the Rotary
Switch mode, turn the rotary switch to OFF and back to any switch
setting.
HOW TO USE THE METER
Pushbuttons
{HOLD BjDisplay Hold
WARNING
TOUCH HOLD WILL NOT CAPTURE UNSTABLE
OR NOISY READINGS. DO N)T TOUCH
HOLD TO DETERMINE THAT CIRCUITS WITH
DANGEROUS VOLTAGE ARE DEAD.
Press (tioLo m) to toggle in and out of the Touch Hold
mode, except if you are already in the MIN MAX
Recording or Frequency Counter mode.
In the Touch Hold mode, the \S annunciator is dis-
played and the last reading is held on the display.
When anew, stable reading is detected, the beeper
emits atone, and the display is automatically
updated. Pressing ijiiS) when you are in the
Touch Hold mode causes you to exit Touch Hold
and enter the MIN MAX Recording mode.
In the MIN MAX Recording mode, press to
stop the recording of readings; press (holoo) again
to resume recording. (Previously recorded read-
ings are not erased.)
In the Frequency Counter mode (Hz), press (
jiaca)
to stop the display; press (noma) again to start it.
11

HOW TO USE THE METER
Pushbuttons
©('")] )Continuity Beeper/Peak MIN MAX
Press C""i )to toggle the beeper on or off for con-
tinuity testing in the ohms function.
The beeper responds as indicated in Table 2.
In the Frequency Counter mode, press («m )to
change the trigger slope from positive-going edges
to negative-going edges. The slope selected is
indicated by the analog display polarity annuncia-
tor (±).
In the MIN MAX mode, press ()to toggle in and
out of the Peak MIN MAX mode. See item 8.
Power-On Option: DItaWe Beeper
When the beeper has been disabled, all beeper functions are
turned off. The beeper Is automatically disabled if the meter is in
the Data Output mode.
(12) Cpel ARelative Readings
Press Cfla A)to enter the Relative mode, zero the
display, and store the displayed reading as arefer-
ence value. The relative mode annunciator (A) is
displayed. Press again to exit the relative
mode.
In the Relative mode, the value shown on the LCD is
always the difference between the stored reference
12
value and the present reading. For example, if the
reference value is 15.00V and the present reading is
14.10V, the display will indicate -0.90V. If the new
reading is the same as the reference value, the dis-
play will be zero.
13) (Hz )Frequency Counter Mode
and Duty Cycle
Press the ()to select the Frequency Counter
mode; press again to select duty cycle (the alternate
counter function); press again to exit The analog
display does not operate in either the Frequency
Counter mode or duty cycle.
In Frequency Counter mode, the Hz annunciator is
displayed. The frequency function autoranges over
five ranges: 199.99 Hz, 1999.9 Hz, 19.999 kHz,
199.99 kHz, and greater than 200 kHz. The RANGE
button manually selects the voltage or current input
range. If duty cycle is selected, readings from 0.0
through 99.9 are displayed. The "Hz" annunciator
turns off and "%" turns on.
Power-On Option: High Input Impedance Mode
The input impedance of the mv function (400 mV range) is
changed from 10 megohms to greaterthan 4000 megohms.
Summary of Power- on Options
You can select anumber of options each time you turn the
meter on. These power-on options (also listed on the rear of

HOW TO USE THE METER
Summary of Power-on Options
the meter) are selected by holding down one or more of the
pushbuttons while turning the function switch to any ON posi-
tion. All power-on options are only disabled when the rotary
switch is turned to OFF. Each power-on option is discussed in
detail under "Pushbuttons" and summarized in Table 3.
Digital and Analog Display
Items 14-19 describe the digital and analog displays and LCD
annunciators.
Table 3. Options Available at Power-on
OPTION PUSHBUTTON FUNCTION
Automatic Power-off BLUE Disable Automatic Power-off
41/2 Digit Mode YELLOW Select 4V2 digit display. Full scale 19,000 counts.
MIN MAX Record Speed MIN MAX Select High Accuracy record speed. (Response time
approximately 1second)
Rotary Switch Test RANGE For servicing purposes only. See 80 Series Service Manual
Data Output HOLD HEnable ultrasonic data transmission. (For use in factory testing
only, cannot be modified for customer use. Beeper functions
disabled.)
Disable Beeper mil Turns off all beeper functions
High Input Impedance
in mV DC Hz Provides >4000 MO input impedance for 400 mV dc range
(14) Digital Display
Digital readings are displayed on a4000-count
display with polarity (±) indication and automatic
decimal point placement. When the meter is turned
on, all display segments and annunciators appear
briefly during aselftest The display updates four
times per second, except when frequency readings
are taken. Then the update rate is 3per second.
13

HOW TO USE THE METER
Digital and Analog Displays
(15) iiiililifiltiiitliiliMllllliiil Analog Display
The analog display is a32-segment pointer that
updates at a40 times per second rate and is the
best display to use for readings that are changing.
It does not operate in the Capacitance or Fre-
quency Counter functions or in the Peak MIN MAX
mode.
For increased sensitivity, the analog pointer moves
across the scale four times for each range. The
pointer returns to (wraps around) when the
equivalent digital display reaches 1024, 2048, and
3072 counts. Select the next higher range if the
pointer is too sensitive.
The analog pointer indicates avalue lower than
the digital display (up to 2.5% of range). Examples
on the 40V range are:
Digital Display =5.00V 15.00V 25.00V 35.00V
Analog Pointer =4.8 4.5 4.5 4.2
Wrap =First Second Third Fourth
Indication =4.8V 14.5V 24.5V 34.2V
14
With stable inputs, use the digital display for the
best sensitivity and precision.
(16) ?„„l„.,f„.,?..„1„„f,„.?M.,L„?,,..?„..? Analog Display Scale
Scale for each 1000 counts in the digital display.
±Analog Display Polarity
Indicates the polarity of the input except in the
Frequency Counter mode, when it indicates the
polarity of the trigger slope (edge).
Input Range Annunciator
Displays 4, 40, 400, or 4,000 input range for volts,
amps, or ohms, and 400 mV.
Overload Indication
Displayed on digital display when input (or math
calculation in REL mode) is too large to display. If
you are taking duty cycle readings, OL is displayed
if the input signal stays high or low. All segments are
illuminated on analog display.
Items 20-23 describe annunciators that indicate the mode or
state in which the meter is operating: