Cause : Watchdog timer has initiated a reset (active in all operating states) An internal microprocessor hardware counter monitors whether the program for calculating the firing pulses runs at least once every 14 ms (program is executed on average every 2.7 to 3.3 ms). If this is not the case, the counter initiates a reset, F064 is then displayed.

Possible fault causes

♦ A7001 electronics board is defective

♦ Excessive EMC-related interference is present (e.g. due to unprotected contactors, unscreened cables, loose shield connections)