Hioki CM4375 Mode D'emploi page 62

Troubleshooting
Symptom
• When readings from the
instrument are compared with
those of another clamp-on
current meter, the measured
values differ.
• The current value is larger than
expected.
• A current value is displayed
even though there is no input.
• A sound is being emitted by the
instrument's jaw.
• The measured value does not
appear.
• No measured value is displayed,
even when the test leads are
shorted.
• Zero adjustment is impossible.
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Verification and/or Solution
• The instrument cannot accurately measure waveforms that contain a
component that falls outside the frequency characteristics range.
• Since the instrument performs true RMS measurement, it can
accurately measure distorted waveforms. When measuring a distorted
waveform, the measured value will differ from a clamp-on current
meter that uses the averaging method.
• The instrument cannot perform measurement accurately in the
presence of a strong magnetic field from a source such as a nearby
transformer or high-current circuit or in the presence of a strong
electric field from a source such as a wireless device.
• The jaw may emit sound when measuring AC currents in excess of
approx. 500 A, however, there is no effect on the measurement.
• Check the continuity of the test leads. (p. 22)
If a wiring break is found, replace the test leads.
• Insert the test leads all the way.
Use the proper measurement method.
If no problem can be found, the instrument may be damaged. Send
the instrument for repair.
• When performing current measurement, perform zero-adjustment
while no measurement target is being clamped.