Cause : FBA A communication comes when cyclical communication between drive and fieldbus adapter module A or between PLC and fieldbus adapter module A is lost.

The A7C1 warning in your ABB ACS560 drive indicates a communication error with the fieldbus adapter module. The fieldbus adapter module is an optional add-on that allows the drive to communicate with other devices using industrial communication protocols like Profibus, DeviceNet, or Modbus.

1. Check status of fieldbus communication.
2. Check settings of parameter groups 50 Fieldbus adapter (FBA), 51 FBA A settings, 52 FBA A data in and 53 FBA A data out.
3. Check cable connections.
4. Check if communication master is able to communicate.