GR8-1200 OEM
Midtronics Inc. 7000 Monroe Street Willowbrook, IL 60527
www.midtronics.com
43
Chapter 14: Digital Multimeter (DMM)
Chapter 14: Digital Multimeter (DMM)
DMM
The GR8’s 8 digital meters make it versatile enough
to test everything from a vehicle’s entire electrical
system to a board-level component:
• DC
Voltmeter
• AC
Voltmeter
• Scope
• DC
Ammeter
• AC
Ammeter
• Ohmmeter
• Diode
Drop
• 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. Specifi cations for each tool
are listed 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 specifi cations 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 parallel with the circuit.
1. Connect the DMM test lead to the GR8’s accessories port.
2. Select the meter’s icon.
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 the
END
s
oft key
.
AC Volts
The AC voltmeter measures the AC volts between two points in
a circuit. The voltmeter is connected in parallel with the circuit.
1. Connect the DMM test lead to the GR8’s accessories port.
2. Select the meter’s icon.
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 the
END
s
oft key
.
Scope
The scope is a voltmeter that provides a graph of voltage
diff erence as it varies over time. After you select the scope icon,
note the instructions in the next screen before proceeding.
You’ll need the them after you press the
NE
X
T
soft key 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 the
NE
X
T
soft key 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 printer
when you freeze the signal. To print, select the
P
RINT
soft key.
To return to the METERS menu, press
END
.
DC AMP
(requires the optional amp clamp)
The DC ammeter measures DC magnitude and fl ow of the DC
current in a circuit.
1. Connect
the
amp clamp lead
to the GR8’s accessories
port.
2. Select the meter’s icon.
3. Select the amp clamp range.
1
70 AMP MAX.
2
700 AMP MAX
.
Press the
NE
X
T
soft key to continue.
4. The meter will zero itself.
5. Place the clamp’s jaws around the negative (–) cable.
6. The GR8 will display the measurement.
7. To return to the METERS menu, press the
END
so
ft key
