18
4) If after the above checks, the instrument still does not start, please contact the
relevant department.
5 Instruction on measurement
Notes:
1. After the voltage up to 1000 VDC is measured, it is better to wait for about 2 minutes,
and then conduct the low voltage measurement with the resolution rate 1 to 10 μV.
2. After using the A input terminal for measuring high currents, it is better to wait for about
10 minutes, and then conduct the low-level DC measurements (volts, amps, or ohms) in
order to achieve accuracy. The reason is that measuring the thermal voltage generated by
the high current may cause errors in the low-level measurements.
3. After the completion of all measurements, disconnect the probe and the circuit under
test and remove the probe from the input end of the instrument.
4. When measuring the high voltage and high current, pay special attention to safety.
5. Because ET3240 / ET3241 / ET3255 share the same measurement method, the
measurement will be explained by taking the operation of ET3255 as an example.
5.1 Voltage measurement
Notes: Make sure that before the measurements, the terminals are connected
correctly. To avoid damages to the multimeter, do not exceed the rating.
5.1.1 DC voltage measurement
Range: 200mV, 2V, 20V, 200V, 1000V
Input protection: the peak of 1000V for all ranges
Measurement method:
1. Press
DC V
to select DC voltage measurement function; it automatically enters
into DC voltage measurement function every time when the instrument is turned on.
The DC voltage measurement interface is shown in Figure 2.1.1:
