Measuring Operation; Data Hold; Dc Current Measurement - Mastech MS8239A User Manual

Measuring Operation

Data Hold

The data hold function can keep the current readings
on the display. To enter and exit reading maintenance
mode:
1 Press the "HOLD" key, the reading will be stored
and "H" symbol will display on the LCD display.
2
Press the "HOLD" key again to return the meter
to the normal measurement state.
AC/DC Voltage Measurement:
1
Rotate the function selection switch to appropriate
AC or DC voltage measurement position.
2
Connect the black and red test probes to the COM
input jack and VΩmA input jack, respectively..
3
Measure the voltage of circuit to be tested with
other ends of test probes (connected with the
circuit to be tested in parallel).
4 Read the measured value from the LCD display.
When measuring the DC voltage, the display will
simultaneously show the voltage polarity which is
connected with the red test probe.
Warning
Don't measure any RMS voltage higher than 600V
DC or AC, to prevent injury or damage to meter
and equipment.
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DC Current Measurement:

Turn off the power to the circuit to be tested.
1
Discharge all the high voltage capacitors on the
circuit to be tested.
2 Rotate the function selection switch to the
appropriate DC current position.
3 Depending on the size of the current to be
measured, connect the red test probe to 10A or mA
input jack; connect the black test probe to COM
input jack.
4
Turn off the circuit to be tested. Connect the black
test probe to one end of the disconnected circuit
(low voltage relatively), and the red test probe is
connected to the other end of disconnected circuit
(high voltage relatively). (Reversing test probes
would make reading become negative, but the
meter won't be damaged.)
5 Connect the power supply to the circuit, then read
the display reading. If the display shows only "1",
the input is out of the selected input range. In this
case, rotate the switch to a higher measuring range.
Warning
To prevent injury or damage to meter and
equipment, do not make current measurements
if voltage exceeds 250V.
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