Modbus TCP Socket Connection Closed, DriverState was Connected

General Discussion
1

I have an Ignition v8.1.1 system that has been running smoothly for the past few years. This morning, customer reported that none of the tags are connected to the PLC. Upon chceking, I found that the device appears to be connected. But after reviewing the logs, I noticed an error message from this morning stating: "Socket connection closed, DriverState was Connected".

PLC in use is a Schneider Electric M580, communicating with Ignition via Modbus TCP. Any insights or suggestions on resolving this issue would be greatly appreciated.

2

This means the TCP connection is being closed on us. You should be able to see and verify this in a Wireshark capture.

There's a lot of reasons this could happen... PLC not configured for Modbus any more, firewall configuration changed, too many other things connected to it, reading an address that no longer exists due to a configuration change, etc...

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3

The issue was resolved by deleting and recreating the device.