Cyborg (Customer) asked a question.
Communicating with an RS-485 Device
I have an RS-485 sensor that we normally use with our in-house manufactured control box. I need to connect it to a BRX controller for a test that we're setting up for it. I've attached its Byte structure and CheckSum calculation. Can someone with superior skills, knowledge, and experience than I have provide some guidance on how to get this thing going on my BRX controller? I know the wiring is correct, the baud rate matches the sensor baud rate, and the rest of the Serial Port settings are correct. Its the CheckSum calculation that I'm wrestling with.
Hi @Cyborg (Customer)
I do not have an exact example for your application, but I have successfully implemented RS-485 communication using Modbus ASCII with a temperature controller. This has been published here:
https://accautomation.ca/brx-do-more-plc-modbus-ascii-protocol/
Here is the video:
https://www.youtube.com/watch?v=X_lzKSIwzrk
I hope this will help you out.
Regards,
Garry
ACC Automation
Thanks Gary! I referenced this video when attempting to solve this problem. The problem with our sensor is the bidirectional nature of its communication. It only does something when its told to. I've sent one of our sensors to Doug and Nick Bell with Interconnecting Automation to see if they can make some sense of it (which I'm fully confident that they can). This being a home grown sensor by us makes it tricky, but having it connect to our BRX controllers will allow us to finish our testing and integrate it with our other products.
Thanks again for taking the time to respond!