Midtronics Inc. 7000 Monroe Street Willowbrook, IL 60527
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21
Chapter 6: DMM (Digital Multimeter)
EXP-1002
The tester’s 8 digital meters make it versatile enough
to test everything from a vehicle’s entire electrical sys-
tem to a board-level component:
•
DC Voltmeter
•
AC Ammeter
•
AC Voltmeter
•
Ohmmeter
•
Scope
•
Diode Drop
•
DC Ammeter
•
Volts/Amp
The DMM’s infrared temperature sensor also enables you to
determine the surface temperature of components before you
service them or as a diagnostic aid. Specifications for each tool
are listed in the table at the end of this chapter.
Select the DMM icon to display its METERS menu. The tools in
this menu are available in a series of three screens.
A measurement that is out of the limit displays as
OL
. Refer to
the manufacturer specifications for the correct limits, which
may vary by component or vehicle type.
DC Volts
The DC voltmeter measures voltage between two
points in a circuit. The voltmeter is connected in par-
allel with the circuit.
1. Connect the DMM test lead to the tester’s accessories port.
2. Use
or
to select the DC Volts icon and press NEXT to
continue, or press the corresponding number key.
3. Connect the clamps or probes in the correct polarity: red
clamp or probe to positive (+); black to negative (–).
4. The meter will autorange and display the measurement.
5. To return to the METERS menu, press END.
AC Volts
The AC voltmeter measures the AC volts between two
points in a circuit. The voltmeter is connected in paral-
lel with the circuit.
1. Connect the DMM test lead to the tester’s accessories port.
2. Use
or
to select the AC Volts icon and press NEXT to
continue, or press the corresponding number key.
3. Connect the clamps or probes in the correct polarity: red
clamp or probe to positive (+); black to negative (–).
4. The meter will autorange and display the measurement.
5. To return to the METERS menu, press END.
Scope
The scope is a voltmeter that provides a graph of
voltage difference as it varies over time. After you se-
lect the scope icon, note the instructions in the next
screen before proceeding. You’ll need the them after
you press SELECT to continue:
•
Press 1 on the keypad to autoscale the scope.
•
Press 3 on the keypad for the time display.
•
Press 4 on the keypad for the FFT (frequency) display.
Press SELECT to continue.
In the time display the horizontal axis is in seconds and the
vertical axis is in volts.
In the frequency display the horizontal axis is in hertz and the
vertical axis is in volts.
Press the right soft key to alternate between the options to
RUN (measure and display the signal) and HOLD (freeze the
signal).
The scope enables you to print the voltage trace to the optional
IR printer when you freeze the signal. Align the tester’s IR
transmitter with the printer’s receiver, and select PRINT.
To return to the METERS menu, press END.
DC Amp
The DC ammeter measures DC magnitude and flow of
the DC current in a circuit.
NOTE: Performing this test requires the optional amp
clamp.
1. Connect the
amp clamp lead
to the tester’s accessories
port.
2. Use
or
to select the DC Amp icon and press NEXT to
continue, or press the corresponding number key.
3. Use
or
to select the Amp Clamp range and press
NEXT to continue, or press the corresponding number key.
The meter will zero itself.
1
70 AMP MAX.
2
700 AMP MAX
.
4. Place the clamp’s jaws around the negative (–) cable.
5. The tester will display the measurement.
6. To return to the METERS menu, press END.
Chapter 6: DMM (Digital Multimeter)
