Modbus not working correctly, device name related?

Ok, I for some reason was getting bad quality on the first 100 words of the project. I figured this was a timing issue since I’m polling through a VPN tunnel right now, so I increased the timeout, and lowered the request size from 125 registers to 10. This seemed to work, but I was still getting bad quality for the first 20 words. This was weird because the quick client in the gateway showed bad quality for the tag, but clicking the [r] next to the tag for read would return the value and a good quality. Frustrated, I fired up a PLC simulator on my local machine to test what needed to be tested and I saw the same results. Deleting the device and recreating it with the same name got the same results. Creating a new device with a new name seemed to make things work correctly.

Any idea what happened for future reference?

Absolutely no idea… the name should have no bearing at all. If you manage to reproduce it give us a call and we can poke around / get some logs to see what’s going on.

Hi Kevin,

Had this issue ever been recorded more than this one post? we are seeing this currently connecting to a Delta PLC via Modbus