Is it possible to ignore Modbus fault when Altivar 71 drive is controlling via Modbus.

Yes, it is possible.

Programming detail of drive:--

FR1=>Modbus

SLL=>[Ignore] (nO): Fault ignored

Working:--

(1) If Command and reference (example 42 hz) come from Modbus channel.

The communication loss will be inhibited, Means that If the motor is in Run (42 Hz), then we disconnect the Modbus cable, the motor will continue to run at 42 Hz (the drive will not trip on modbus fault -  SLF1).

(2) If we connect the Modbus cable (means communication resume) then drive will continue to run at 42Hz (no need to give command & reference)

(3) If you want to change the reference, then you can change the reference only i.e. 35 Hz via controller & no need to give command. =>ATV71 drive will take the new reference from the controller.