Posted 15 Jun 2020 (edited) Hello, I'm trying to execute the loopback test on the RS-422 built-in port of GX3GE-40M. I connected the TxD pins to RxD pins (+ to +, - to - ). I'm trying to use the function rs2 (later the plc should communicate with a bar code reader). I have tryed all possible connections, to see if the PLC can read the signal as well as transmit it. It manages to transmit the signal, but I cannot get it to read it. Could someone help me troubleshoot if the problem is in the program portion? I'm working in GX Works2 Thanks for any and all help test_plk.gxw Edited 15 Jun 2020 by Becky Share this post Link to post Share on other sites
