Tenma 72-7740, 72-7745 Operating Manual
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Unpacking Inspection
Rules For Safe Operation
Title
Page
Table of Contents
1
D. Continuity Test
International Electrical Symbols
AC Voltage Measurement
Capacitance Measurement
The Use of Relative Value Mode
The Meter Structure
Turning on the Display Backlight
General Specifications
Resistance
Overview
Safety Information
Rotary Switch
Functional Buttons
Display Symbols
Measurement Ranges
A.
B.
Measurement Operation
A.
B.
C.
D. Testing for Continuity
E.
F.
G.
H.
I. Temperature Measurement
J.
Operation of Hold Mode
The POWER Button
The BLUE Button
Sleep Mode (Model 72-7740 only)
Accuracy Specifications
A. DC Voltage
B. AC Voltage
C.
Selecting a Measurement Range
Manual Ranging and Autoranging
DC Voltage Measurement
Measuring Resistance
Frequency Measurement
DC or AC Current Measurement
Testing Diodes
Measuring Duty Cycle
Model 72-7740/72-7745: OPERATING MANUAL
Capacitance
Frequency & Duty Cycle
DC Current
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Page
2
J. AC Current
Maintenance
A. General Service
B. Testing the Fuses
C. Replacing the Battery
D. Replacing the Fuses
RS232C Serial Port (Model 72-7745)
A. RS232C Port Cable
B. Setting of RS232C Serial Ports
C. System Requirements for
Installing the serial Interface Program
Diode Test
I.
E.
F.
G.
H. Temperature
Model 72-7740/72-7745: OPERATING MANUAL
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Overview
This Operating Manual covers information on safety and
cautions. Please read the relevant information carefully
and observe all the Warnings and Notes strictly.
Warning
To avoid electric shock or personal injury, read the
“Safety Information” and “Rules for Safe Operation”
carefully before using the Meter.
Digital Multimeter Model 72-7740 (hereafter referred to
as “the Meter”) have autorange and manual range options
with maximum reading 3999. The enclosure structure
design adopted advanced “co-injection” technique in
order to provide sufficient insulation.
Model 72-7740/72-7745: OPERATING MANUAL
Qty
1 piece
1 pair
1 pair
1 piece
1 piece
Item
1
2
3
4
5
Description
Operating Manual
Test Lead
Test Clip
CAT IV: Primary supply level, overhead lines, cable
systems etc.
4
Unpacking Inspection
Open the package case and take out the Meter. Check the
following items carefully to see any missing or damaged part:
In the event you find any items missing or damaged,
please contact your dealer immediately.
Safety Information
This Meter complies with the standards IEC61010: in
pollution degree 2, overvoltage category (CA T. III 1000V ,
CAT. IV 600V;)and double insulation.
CAT. III: Distribution level, fixed installation, with smaller
transient overvoltages than CAT. IV
Use the Meter only as specified in this operating manual,
otherwise the protection provided by the Meter may be
impaired.
In this manual, a Warning identifies conditions and
actions that pose hazards to the user, or may damage
the Meter or the equipment under test.
A Note identifies the information that user should pay
attention to.
International electrical symbols used on the Meter and
in this Operating Manual are explained on page 6.
Point Contact Temperature Probe
9V Battery (NEDA1604, 6F22 or 006P)
(installed)
Model 72-7740/72-7745: OPERATING MANUAL
Rules For Safe Operation
To avoid possible electric shock or personal injury, and to
avoid possible damage to the Meter or to the equipment
under test, adhere to the following rules:
l Before using the Meter inspect the case. Do not use the
Meter if it is damaged or the case (or part of the case) is
removed. Look for cracks or missing plastic. Pay
attention to the insulation around the connectors.
l Inspect the test leads for damaged insulation or exposed
metal. Check the test leads for continuity. Replace
damaged test leads with identical model number or
electrical specifications before using the Meter.
l Do not apply more than the rated voltage, as marked on
the Meter, between the terminals or between any
terminal and ground.
l The rotary switch should be placed in the correct
position and no change of range made during
measurement , to prevent damage of the Meter.
l When working at an effective voltage over 60V
DC or 30V rms AC, special care should be taken
there is danger of electric shock.
l Use the proper terminals, function, and range for your
measurements.
l Do not use or store the Meter in an environment of high
temperature, humidity, explosive, flammable and
strong magnetic field. The performance of the Meter
may deteriorate after dampened.
l When using the test leads, keep your fingers behind the
finger guards.
l Disconnect circuit power and discharge all high-voltage
capacitors before testing resistance, continuity, diodes,
current, or capacitance.
l Before measuring current, check the Meter’s fuses and
turn off power to the circuit before connecting the Meter
to the circuit.
l
Replace the battery as soon as the battery indicator " "
appears. With a low battery, the Meter might produce
false readings that can lead to electric shock and
personal injury.
l Remove test lead, temperature probe, RS232C interface
Warning
5
Model 72-7740/72-7745: OPERATING MANUAL
cable and test clip from the Meter and turn the Meter
power off before opening the case.
l When servicing the Meter, use only the same model
number or identical electrical specifications replacement
parts.
l The internal circuit of the Meter shall not be altered at
will to avoid damage of the Meter and any accident.
l Soft cloth and mild detergent should be used to clean the
surface of the Meter when servicing. No abrasive and
solvent should be used to prevent the surface of the Meter
from corrosion, damage and accident.
l
l
l
l
The Meter is suitable for indoor use.
Under the environment with high (+/-4kV) electrostatic
discharge, the Meter may not be operated as normal
condition. The user may require resetting the Meter.
Remove the battery when not used for a prolonged
period to avoid damage to the Meter.
Please constantly check the battery as it may leak
when it has been using for some time, replace the
battery as soon as leaking appears. A leaking battery
will damage the Meter.
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International Electrical Symbols
AC (Alternating
Current)
Deficiency of Built-In
Battery
DC (Direct Current) Continuity Test
AC or DC Diode
Grounding Capacitance Test
Double Insulated Fuse
Warning. Refer to the
Operating Manual
Conforms to Standards
of European Union
Model 72-7740/72-7745: OPERATING MANUAL
l
Periodically check the battery as it may leak after
some time. If leakage is apparent,the battery should
be immediately replaced to prevent damage.
The Meter Structure (see figure 1)
(figure 1)
1 LCD Display
2 Functional Buttons
3 Rotary Switch
4 HzV
Input Terminal:
Input for voltage, frequency/duty cycle, resistance, diode,
continuity and capacitance measurements.
5 COM Input Terminal:
Return terminal for all measurements.
Input Terminal:
Input for 0.1 A to 400.0mA current measurements and
temperature testing.
7 10A Input Terminal:
Input for 0.01A to 10.00A current measurements.
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Model 72-7740/72-7745: OPERATING MANUAL
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Rotary Switch
The table below provides information about rotary switch
positions.
Rotary
Switch
Position
Function
V DC voltage measurement range from 400.0mV to
1000V or
AC voltage measurement range from 4.000V to
750.0V.
Continuity test.
Diode test.
Resistance measurement range from 400.0
Temperature in celsius
Hz Frequency measurement range from 10.00Hz to
10.00MHz.
AC or DC current measurement range from
A.
mA AC or DC current measurement range from
40.00mA to 400.0mA.
A AC or DC current measurement range from
4.000A to 10.00A.
to 40.00M .
Model 72-7740/72-7745: OPERATING MANUAL
Functional Buttons (1)
9
The table below provides information about functional
button operation.
Button Measuring
Function
Operation Performed
POWER Any rotary
switch
position
Turn the power on and off.
V
Switches between AC and DC
voltage; the Meter beeps. DC is
default.
Switches between continuity and
diode and resistance and
capacitance measurements; the
Meter beeps.
Resistance is default.
Switches between AC and DC
current range from 400.0 A to
4000 A; the Meter beeps. DC is
default.
mA
Switches between AC and DC
current range from 40.00mA to
400.0mA; the Meter beeps. DC is
default.
A
Switches between AC and DC
current range from 4.000A to
10.00A; the Meter beeps. DC is
default.
Disable Sleep Mode feature.
(BLUE)
Model 72-7740/72-7745: OPERAT ING MANUAL
RANGE
Any rotary
switch
position
exceptHz
and
l Press RANGE to enter the
manual ranging mode; the Meter
beeps.
Manually selecting a range causes
the Meter to exit the Hold and REL
modes.
l Press RANGE to step through
the ranges available for the
selected function; the Meter beeps.
l Press and hold
RANGE
for 2
seconds to return to autoranging;
the Meter beeps.
Hz
1. Press to start the frequency
counter; the Meter beeps.
2. Press again to enter duty cycle
mode; the Meter beeps.
3. Press again to return to the
frequency counter mode; the Meter
beeps.
Hz %
V , ,
mA or
A
1. Press to start the frequency
counter; the Meter beeps.
2. Press again to enter duty cycle
mode; the Meter beeps.
3. Press again to return to the
previous measurement mode; the
Meter beeps.
REL
Any rotary
switch
position
except Hz
Press to enter
and exit the REL mode in any
measuring mode except in
frequency/duty cycle; the Meter
beeps.
Any rotary
switch
position
Press HOLD H
to enter and exit
the Hold mode in any mode, the
Meter beeps.
REL
Functional Buttons (2)
HOLD H
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Model 72-7740/72-7745: OPERAT ING MANUAL
Display Symbols (1)
(see figure 2)
Number Symbol Meaning
1AC Indicator for AC voltage or current.
Model 72-7740: The displayed value is the
mean value.
Model 72-7745:The displayed value is
the true rms value.
2 TRMS Model 72-7745: Indicator for true rms
value.
3 The Meter is in the auto range mode in
which the Meter automatically selects the
range with the best resolution.
4 RS232CData output. It is always on the LCD, but
data output is only in progress when the
Meter is connected to the computer via the
included RS232C Interface Cable.
5 % Percent: Used for duty cycle measurements.
6
Data hold is active.
7
The REL is on to display the present value
minus the stored value.
8
The battery is low.
Warning To avoid false readings,
which could lead to possible electric shock
or personal injury , replace the battery as
soon as the battery indicator appears.
9 Centigrade. The unit of temperature.
10
Diode test.
11 The continuity buzzer is on.
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3
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6
7 8 9
10
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12 ~ 16
17
(figure 2)
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Model 72-7740/72-7745: OPERAT ING MANUAL
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