Hioki DSM-8542, Instruction Manual, Page: 134 / 140

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10. Maintenance
Periodical checks and calibrations are recommended to ensure reliability of test data of the
meter and to prevent accidents.
HIOKI E. E. Corporation is on hand to make checks, repairs and calibrations of your meter.
10.1 Periodical Checks for Maintenance
(1) Visually check external damage such as on measuring terminals and panels.
High voltage up to 1000V is impressed to the meter. A damaged measuring
terminal or other part is hazardous and causes an accident.
(2) Clean the panel surfaces and areas around the terminals and connectors on the
rear using a clean cloth.
(3) Visually check that the display screen is clear.
(4) Check that the keys, switches and other parts operate smoothly and correctly.
(5) Measure measuring voltage output using a voltmeter and check that voltage
errors are within 3% of set values.
Measure measuring voltage output between shielded-conductor cables of the
“OUTPUT” and “INPUT” terminals.
10.2 Calibration
This meter calculates the insulation resistance value of a sample based on measuring
voltage impressed to the sample and on measured current value.
The resistance measurement accuracy of this meter is calibrated by calibrating the output
voltage accuracy and current measurement accuracy.
First, calibrate the output voltage using a voltmeter with an accuracy of 0.01% or higher.
Then connect calibrated reference resistance and calibrate the current measurement
accuracy.
In case calibration results are outside the DC current measurement accuracy mentioned in
Paragraph 2.1.1, please contact HIOKI E. E. Corporation for adjustment of your meter.
10.2.1 Equipment needed for calibration
The following equipment is needed for calibration.
Voltmeter Measurement accuracy 0.01% or higher
Reference resitances 1M Ω , 10M Ω , 100M Ω , 1G Ω , 10G Ω , 100G Ω , 100k Ω
Shielding box
10.2.2 Calibration of measuring voltage
Measure voltage between output between shielded-conductor cables of the “OUTPUT”
terminal and “INPUT” terminal.
10.2.3 Calibration of current measurement
Set an integral time of 300ms, Internal Trigger mode, averaging ON and self-calibration of
60s when measuring a current.
Place the reference resistance in the shielding box for shielding to reduce impacts by noise.