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6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions
Operation panel
indication
E.CPU
E. 5
E. 6
E. 7
Name
CPU fault
Description
The inverter trips if the communication fault of the built-in CPU occurs.
Check point
Check for devices producing excess electrical noises around the converter unit.
Corrective action
• Take measures against noises if there are devices producing excess electrical noises around the converter
unit.
• Contact your sales representative.
Operation panel
indication
E.CTE
Name
Operation panel power supply short circuit/RS-485 terminals power supply short circuit
Description
• When the power supply for the operation panel (PU connector) is shorted, the power output is shutoff and the
inverter output is shut off. At this time, the use of the operation panel and the RS-485 communication via the
PU connector are disabled.
To reset, enter the RES signal from the terminal, reset through communication via the RS-485 terminals, or
switch power OFF then ON again.
• When the power supply for the RS-485 terminals are short circuited, this function shuts off the power output.
At this time, communication from the RS-485 terminals cannot be made.
To reset, use
on the operation panel, enter the RES signal, or switch power OFF then ON again.
Check point
• Check that the PU connector cable is not shorted.
• Check that the RS-485 terminals are connected correctly.
Corrective action
• Check the operation panel and the cable.
• Check the connection of the RS-485 terminals.
Operation panel
indication
E.P24
Name
24 VDC power fault
Description
• When the 24 VDC power output from the PC terminal is shorted, this function shuts off the power output.
At this time, all external contact inputs switch OFF. The inverter cannot be reset by entering the RES signal.
To reset it, use the operation panel, or switch power OFF, then ON again.
Check point
• Check for a short circuit in the PC terminal output.
• Check that the 24 V external power supply voltage is correct.
Corrective action
• Repair the short-circuited portion.
• Supply the power at 24 V. (If the power with insufficient voltage is supplied to the 24 V input circuit for a long
time, the inverter internal circuit may heats up. Although it will not damage the inverter, supply power at the
correct voltage.)
Operation panel
indication
E.IOH
Name
Inrush current limit circuit fault
Description
The inverter output is shut off when the resistor of the inrush current limit circuit is overheated. The inrush current
limit circuit is faulty.
Check point
• Check that frequent power ON/OFF is not repeated.
• Check if the input side fuse (5A) in the power supply circuit of the inrush current limit circuit contactor is blown.
• Check that the power supply circuit of inrush current limit circuit contactor is not damaged.
Corrective action
Configure a circuit where frequent power ON/OFF is not repeated.
If the problem still persists after taking the above measure, contact your sales representative.
Operation panel
indication
E.SER
Name
Communication fault (inverter)
Description
The inverter output is shut off when communication error occurs consecutively for the permissible number of
retries or more when
Pr.335 RS-485 communication retry count
≠
"9999" during RS-485 communication
through the RS-485 terminals. The inverter output is also shut off if communication is broken for the period of
time set in
Pr.336 RS-485 communication check time interval
.
Check point
Check the RS-485 terminal wiring.
Corrective action
Perform wiring of the RS-485 terminals properly.
