In a running project I am making communication between FX-2n PLC and FRF-540J Inverter through FX2N RS485BD.There are 4 nos of drive. In our present program we can read the output frequency from the drives and can write the speed reference to the drive which has been tested successfully. I also need to give run command and stop command to the drives through RS communication. My program with frequency read & write is enclosed. Please help? Sudip 4_Drive_communication.zip