dear sir,
we have 4 instrument air compressor operating in MCC, No 1 compressor is master control for 3 compressors.we have one problem in atlas copco instrument air compressor no 3 this is not communicating with instrurment air compressor 1 and not sending to DCS also it means all process parameters like lube oil pressure,air in/outlet temp and omore analog out puts not showing in DCS but locally everthing is ok
question is how to check communication for lan to Field bus to modbus?

normally connection is Lan to field bus to modbus but reamaining compressors that is 1 2 4 are communicating good but no 3 is not communicating to no 1 compressor and DCS also how to trouble shoot?
Note: Master compressir is recieving all communications from each compressors and finally sending to DCS through MOD bus
please give me ur advise to trouble sohoot by us

Atlas copco
model no :ZT 200
Electronikon PLC
type : screw copressor
stages : 2stage