I have a APC (liebert type a/c),has 2 seperate direct drive / frequecy drive motors. One of the 2 drives is shot (GE Fuji drive).It has no local display on it and the main microprocessor has some access to its running parameters,my question is the drive controlled directly by the microprocessor via modbus or something proprietary.i'm trying to figure how the drive knows what parameters it needs to run at,perhaps its preconfigured from apc and has to be purchased thru apc in order for it to operate.Any help appreciated the books i read had limited info.