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What can cause the InF fault in the Altivar 31 and Altivar 312 drives?

Issue:
InF fault on the Altivar 31 and ATV312 drives.

Product Line:
Altivar 31 and ATV312 drives

Environment:
All

Cause:
Internal fault

Resolution:
InF indicates an internal fault.
It can occur if there are loose connections inside the drive or if the drive is subjected to electromagnetic interference. Check the line voltage to the drive.
Also, check the voltages on the control terminals, +10 to COM and 24V to COM. It has been observed that improper wiring of the inputs or external potentiometer can overload the internal power supplies of the drive. This may result in InF fault.
Incorrect connections on the RJ45 ModBus/CANopen port can also cause this. Verify wiring, particularly to pin 7 (10VDC supply for external keypad).