Posted 29 Jun 2018 i am using a VSD Altivar71 and controlling it through serial MODBUS communication, the probllem is sometimes after stoping the motor the drives gives the "nst" fault which means according to the programming catalouge "freewheel stop" it doesn't do that all the time but it happens a lot and after uploading the code again to plc the problem is gone for a while before it happens again. i am sure that the fault is happening because if communication because when i controll the drive from hmi it never gives that fault, i checked the setting and tried different cables but it still gives "nst" and motor never moves, i found that in catalouge but i am not sure how to address the problem. Share this post Link to post Share on other sites