I am trying to connect a new device using Modbus to a system that's been operational for 8 years and has been updated several times. I've used this device on other systems without issue. I have a UDT that I've used before that's connected and it's polling several data points. What's interesting is that if I change the tag group on one of the tags it will usually connect and stay connected. Sometimes I have to do it a few times. Once connected, it will stay connected for a long time. If I power cycle either the device or server, or if I disable the Modbus connection, then it won't reconnect. I have a wireshark file that might be useful, but I don't see a way to upload it. Any ideas? I have also set up Ignition on my laptop and if I connect it to the device, everything works fine. The modbus driver is 7.1.54. The system is running Ignition 8.1.50. Do I need to update the Modbus driver?
How big is the wireshark file? Try zipping and uploading here. If too big though, you'll have to host it elsewhere and send a link
AMMPS working.pcapng (86.8 KB) The file is not big, so I uploaded it. ip.addr == 172.21.43.210
Correction, it's Ignition 8.1.54, so I believe the modbus module is the correct version.
In the wireshark file, the first 15 seconds are where it's not connecting properly. After that, I changed the tag group and it started working.