I'm trying to implement communication between cRIO-9035 and Kinco FD422S servo controller. I tested communication from PC using NI OPC server with USB - RS485 converter and everything works OK. The problem is in implementing communication from real-time target cRIO-9035.
I tried using LabView Modbus API from Real-Time Module as well as Modbus I/O Server and also unofficial MODBUS Library for LabVIEW. In all cases I wasn't succesfull. I hooked up an oscilloscope and find out strange distorted frames. Please advise me what could be the reason for that?
I wired RxD- with TxD- togehter as well as RxD+ with TxD+ on both ends of cable. I tried connecting and disconnecting grounds.