Hi I am working with an LS Master-K120 PLC. I have managed to write a simple program and download it to the PLC. This was done using RS-232 and COM1. Now I am trying to connect using an OPC server. I happen to be using KepServer. Following the PLC manual's instructions, I modified my serial cable and configured my parameters. Then I added the device using KepServer, but could not connect. I found a small application at the PLC manufacturer website called the Cnet frame editor. I also failed to connect with this application. Only timeout errors. I've checked and double checked my basic parameters (station number, baud rate, parity, data/stop bits). I've sent my question multiple times here (http://eng.lsis.biz/), but LS has not responded. If I can figure out how to connect to the PLC using Cnet Frame Editor, I can move on. Until then I'm stuck. I'm really banging my head. I hope someone here has worked with this PLC.