Mitsubishi Electric MELSEC-Q QE81WH4W User Manual page 102

9 Troubleshooting
9.2.4 If the electric current and voltage that are measured using this module do not match with the ones
measured with other gauge
Table 9.2.4-1 If current and voltage that are measured using this module do not match with the ones
Check item
Are primary current, and input
voltage correct?
Does the compared gauge measure
the effective value correctly?
Is the secondary of CT
short-circuited?
Are you using other current sensor
than recommended ones?
Are you using the voltage transform
unit?
Do you connect the voltage transform
unit has been done correctly?
measured with other gauge
Check the value in the buffer memory for checking
input current and primary voltage. When the value
in the buffer memory is changed, you need to turn
the request for operating condition setting into
ON. Otherwise, it will not be applied to the
measurement.
This module stores the effective value into the
buffer memory. If the compared device uses the
average value instead of the effective value, the
resulted value may largely differ when there is
current distortion in the measurement circuit.
Make sure that the secondary of CT is not
short-circuited. If it is connected to Mitsubishi's
current transformer CW-5S(L), check that the
secondary switch is not short-circuited.
Only the dedicated current sensors can be
connected to this module. Check that other
company's sensor is not being used.
Circuit voltage can not be entered directly into this
module. Enter the output voltage of the voltage
transform unit (QE8WH4VT).
Please check whether wiring of the is voltage
transform unit performed correctly.
9 - 5
Action
QE81WH4W
Reference
Section
6.1
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