Version VisiLogic V9.7.9
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When configuring the COM port to MODBUS the break signal switches the com port to RS232 PCOM and then you are unable to communicate with the PLC.
There is a system bit that turns on when break signal occurs SB 330,331, and 332 for COM port 1, 2, and 3 respectively. You can use this system bit to change the com port setting to RS485 again (since the break signal changes it to RS232 by default).
As you can see in the attached application after the SB 331 for COM 2 rises, we wait 5 seconds and change the com port settings to RS485. The disadvantage of this workaround is that you will need to tr