Communication to Modbus/TCP elements drops down every 40-60 seconds

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1

Hello all
we are having approx. project of 15 (Phoenix contact) Modbus converters - behind them groups of 30 RTU elements each.
4 of the converters readings are not stable: every 40-60 seconds it drops down for 1-2 seconds/
We slowed down the timeout of the device gateway up to 10000 - no success.
Any ideas?

2

Do you know what the Phoenix Contact converters have as an idle timeout? If you don't have at least one subscription item guaranteed to read that fast (for each), the converter may be the piece that is timing out. This would be visible in Wireshark captures.

3

Thank you !
How would you suggest to filter with Wireshark.
and which result to expect.

4

We set the Phoenix Contact converter timeout from 100 up to20000ms.

5

You may also want to set the "Reconnect After Consecutive Timeouts" setting on the driver to false.

6

Problem solved!
I increased the Idle Force Timeout Characters to 100 (default = 10).

Thanks!!!

7

Eww! That kind of tweak should not be needed for Modbus TCP. Are you using Modbus RTU over TCP? That is quite different. What model converter is this?