Installation and wiring
Operation while the 24 V external power is supplied
● Faults history and parameters can be read and parameters can be written (when the parameter
write from the operation panel is enabled) using the operation panel keys.
● The safety stop function is invalid during the 24 V external power supply operation.
● During the 24 V external power supply operation, monitored items and signals related to inputs
to main circuit power supply, such as output current, converter output voltage, and IPF signal, are
● The faults, which have occurred when the main circuit power supply is ON, continue to be output
after the power supply is changed to the 24 V external power supply. Perform the inverter reset
or turn OFF then ON the power to reset the faults.
● The retry function is invalid for all faults during the 24 V external power supply.
● If the power supply changes from the main circuit power supply to the 24 V external power supply
while measuring the main circuit capacitor's life, the measurement completes after the power
supply changes back to the main circuit power supply (Pr. 259 = "3").
● The output data is retained when "1 or 11" is set in Pr. 495 "Remote output selection".
Inrush current equal to or higher than the 24 V external power supply specification may flow at
power-ON. Confirm that the power supply and other devices are not affected by the inrush cur-
rent and the voltage drop caused by it. Depending on the power supply, the inrush current pro-
tection may be activated to disable the power supply. Select the power supply and capacity
When the wiring length between the external power supply and the inverter is long, the voltage
often drops. Select the appropriate wiring size and length to keep the voltage in the rated input
In a serial connection of several inverters, the current increases when it flows through the inverter
wiring near the power supply. The increase of the current causes voltage to drop further. When
connecting different inverters to different power supplies, use the inverters after confirming that
the input voltage of each inverter is within the rated input voltage range. Depending on the
power supply, the inrush current protection may be activated to disable the power supply. Select
the power supply and capacity carefully.
"E.SAF or E.P24" may appear when the start-up time of the 24 V power supply is too long (less than
1.5 V/s) in the 24 V external power supply operation.
"E.P24" may appear when the 24 V external power supply input voltage is low. Check the external
power supply input.
Do not touch the control circuit terminal block (circuit board) during the 24 V power supply oper-
ation (when conducted). Otherwise you may get an electric shock or burn.
2 - 53