Change COM port settings dynamically

2022-03-15T10:35:09.799000Z

Hi. It works for me.
See my video snippet:
https://ftp.owen.ru/CoDeSys3/99_ForumFiles/ModbusChangeBaudrate.mp4

At first, both in the CODESYS and on the PC, the baudrate is set to 9600 - and the communication works. Then I change the baudrate to 19200 in the codesis from IEC-code - the communication stops (because the PC is still 9600). Then I set on PC 19200 - and the communication works again.

Change COM port settings dynamically

2022-03-11T10:12:01.523000Z

Unfortunately it doesn't work.

I want to read the current COM settings so I found the SysComGetSettings function in the SysCom library.
But do I set the hComPort RTS_IEC_HANDLE to the serial port COM1?

rtsResult            : RTS_IEC_RESULT;
stComPortSettings    : SysCom.ComSettings;
hComPort             : RTS_IEC_HANDLE;

**hComPort := ????**
rtsResult := SysComGetSettings(hCom:= hComPort, pSettings:= ADR(stComPortSettings), pSettingsEx:= 0);

Change COM port settings dynamically

2022-02-14T13:18:04.813000Z

I think you should use it this way:

eSmart07_RTU.xStop := TRUE;
eSmart07_RTU.Enable := FALSE; // maybe not necessary
eSmart07_RTU.UpdateComParameters(...);
eSmart07_RTU.Enable := TRUE; // maybe not necessary
eSmart07_RTU.xStop := FALSE;

Before using Enable property you should: Device - Plc Settings - Activate diagnostics for devices

Perhaps, Enable is not necessary, and xStop will be enough...

Фnd thanks for the compliment, it's very encouraging.

Change COM port settings dynamically

2022-02-14T12:15:50.143000Z

Hi E.Kislov,

I had already tried this method, which is called during every PLC cycle but it doesn't seem to affect/change the COM port settings.
Maybe there is something else that needs to be done first.

eSmart07_RTU.UpdateComParameters(
udiBaudrate:= BaudRate,
usiMedium:= 1,
usiParity:= 2,
usiDataBits:= 8,
usiStopBits:= 1,
xPolarization:= FALSE,
COMPORT:= 1);

BTW you make great Codesys videos on YT.

Change COM port settings dynamically

2022-02-08T10:27:52.305000Z

Hi.
You can use method of Modbus Master: UpdateComParameters.

Keep in mind that you will need to call this method every time the controller is loaded, because when the runtime starts, the values will be overwritten by those set in the project tree.

Change COM port settings dynamically

2022-02-07T15:20:02.716000Z

Hi,

I want to be able to change the baud rate of the COM port dynamically in runtime.
Anyone know how to achieve it?

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