Posted 31 Mar 2019 (edited) I have an older Omrom PLC with some input cards and a solid state output card. ID211 and OD203. I have another PC controlled device (microcontroller with 24v I/Os) and I want to send and receive simple commands ( a number between 0 and 255). I have three input lines and three output lines. Both talkers could act as a master. To send a number to the PLC, I plan to use the following format. Raise pin1(attention). Toggle pin2 (CLK) at ~20 HZ for eight toggles. Pin3 will be the data and change on the rising clock edge. After the word is transferred, (attention goes to zero) the PLC will act accordingly. This protocol is just a thought. My intent is to transfer data to and from the PLC. The rate as described will be about 2-3 bytes per second or faster if there is a minimal baud rate for a particular instruction). What "instructions" would be best for this type of command transfer? I have it working with a page of KEEPs, MOVs, and COUNTs. I would like something cleaner. Thanks Edited 1 Apr 2019 by graemeian Share this post Link to post Share on other sites
Posted 2 Apr 2019 I only need about 20 different modes so I used a two digit counter method. It gives me plenty of different combinations. For example, the flag pin is raised. One pin toggles 6 times and the other toggled 7, I now have 67 when the flag pin is lowered. Share this post Link to post Share on other sites
Posted 3 Apr 2019 Do you mean RS232C communications or just pulsing digital I/O? What's the model of your Omron PLC? Share this post Link to post Share on other sites
