How can I reset the error code A0503 on siemens micromaster inverter M440?

Question

The inverters are networked on profibus which is linked to the PLC.

Answer 1

generally best solution is to power off inverter to give it a restart, i'm not familliar with the specific model but thats a general issue with inverters.

have you got the original documentation in your O&M's describing what the fault codes mean?
normally it'll be a overcurrent or Undervoltage fault that trips them out.