Hioki 3155-01, Instruction Manual

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5.3 Earth Leakage Current Measurement Mode (ME Equipment)
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5.3.3 Zero Adjustment (Earth Leakage Current)
Table tap
Insulating transformer
NOTE
In cases where the extension cable (power socket conversion cable, table tap,
etc.) is connected to the auxiliary power socket when making a measurement,
the measured value may be subject to leakage current of the extension cable.
In which case, to obtain an accurate measurement, perform zero adjustment
before measuring.
Value of leakage current in the extension cable to be offset by zero adjustment
varies depending on if voltage is applied or not. Zero adjustment is performed
in the condition that voltage is applied.
Value determined by zero adjustment is saved after power is turned off. It is
effective unless changing supply voltage and/or the extension cable.
Zero Adjustment
1. Display the earth leakage current measurement
screen.
2. Connect the extension cable to the auxiliary power
socket. In this case, do not connect the equipment to
be measured to the extension cable.
3. Press the key on the screen to perform zero
adjustment. When zero adjustment is finished, is
displayed on the measuring mode screen, and
indicates that zero adjustment is effective. Press the
key again, and zero adjustment is cancelled, the
normal measured value returns and disappears.
In all equipment to be measured, zero adjustment defaults to the combination
of normal condition with normal polarity and switches back to previous
condition and polarity of the equipment to be measured.
During manual measurement, condition and polarity settings may cause zero
adjustment value to fail to set to zero.