Problem with Modbus RTU Master, stops after 11 tries

Development Tools PLC IDE
1

First: the problem is on Opta + Portenta Machine control the same
I created Generic_Modbus_1 -> Modbus FC-03-1, inserted the remote start register and count. Modbus starts reading with the polling time entered and writes the remote register content to a shared variable. All works fine. When I disconnect the the remote slave and monitor the RS485 line I see that the driver send the request 11 times and stops sending forever. We cannot accept this in our production line. Some devices are temporary offline (over night, line errors, power off condition for maintenance ...). We cannot press the reset button each time the remote device is offline. Where can I disable the stop function?

BR

2

Yes I faced same problem with ST programming using Arduino PLC IDE. However, using normal Arduino IDE and sketch (using C/C++ code), this is not happening, that means when we take out the MODBUS RTU slave (in our case a third party temperature and humidity sensor) and after some time (may be one hour) add it again then things are restoring to normal without doing Opta reset.

3

This can be done with following Structured Text code in Opta -

IF sysMbMRtuNetList[0].pres = FALSE THEN
    LED_G := FALSE;
    LED_R := TRUE;
ELSE 
    LED_G := TRUE;
    LED_R := FALSE;
END_IF;
IF sysMbMRtuNetList[0].slaveNoResponseCount >= 10 THEN
    sysMbMRtuNetList[0].slaveNoResponseCount := 0;
END_IF;
4

Thank you!
This looks like to be the solution to my problem as well!