Two serial devices in parallel

2020-02-27T17:44:31.782000Z

Hi,

you could remove this line, make no sense.
portnum := COM.SysCom.SYS_COMPORT1;

only:

[SysCom]Linux.Devicefile=/dev/ttyO
is needed.

BR
Edwin

Two serial devices in parallel

2020-02-27T17:44:28.701000Z

Hi,

It works like a charm now. I used udiPort 3 and 5 as you suggested!

Leaving the CODESYSControl.cfg unchanged as i wrote it in my last post, The mapping between tty and COM in codesys is of the type: ttyOx -> COM(x+1), isn't it ? Hence, why must the udiPort be equal to 1, if i use only one uart port (e.g. ttyO2) ? What is the meaning of ```

portnum := COM.SysCom.SYS_COMPORT1;

``` in CODESYSControl.cfg when two or more ports are used ?

Sorry to bother you with all these questions but i'd like to understand better how the serial mapping works. It may be also useful to others.

Thank you.

Two serial devices in parallel

2020-02-27T17:44:27.644000Z

hi,
have you tried
FirstSerialLine( slMode:= SL_READWRITE, udiPort:= 3, //ttyO2
and
FirstSerialLine( slMode:= SL_READWRITE, udiPort:= 5, //ttyO4

another one posibility is to set symbolic links for your ports... in Linux.

BR
Edwin

Two serial devices in parallel

2020-02-27T17:44:24.694000Z

Hello,

I'm struggling to figure out a way to communicate with two serial devices in codesys v3.5 SP9 + BBB rev C.

I use both uart2(ttyO2) and uart4(ttyO4) ports. I can successfully communicate using only one uart port by appending the following line in /etc/CODESYSControl.cfg:

[SysCom]
Linux.Devicefile=/dev/ttyO
portnum := COM.SysCom.SYS_COMPORT1;

I use the example project available in the store: SerialComWithVisu with the following call to the FB Serial_Line

FirstSerialLine(
      slMode:= SL_READWRITE, 
      udiPort:= 1, //tty02 ??? 
      udiBaudrate:= 115200,
      paParity:= COM.PARITY.NONE,
      sbStopBits:= COM.STOPBIT.ONESTOPBIT,
      udiByteSize := 8);

Everything works fine. I can write and read out of ttyO2.

Then i added the uart4 (ttyO4). I wired Tx4 -> Rx2 and Tx2 ->Rx4. I tested the communication with a python script and i was able to read and write from both serial devices.

Following the thread http://forum.codesys.com/viewtopic.php?f=21&t=5699&start=15, i left unchanged the CODESYSControl.cfg and i added a second call to the FB setting 2 as COM2

SecondSerialLine(
      slMode:= SL_READWRITE, 
      udiPort:= 2, 
      udiBaudrate:= 115200,
      paParity:= COM.PARITY.NONE,
      sbStopBits:= COM.STOPBIT.ONESTOPBIT,
      udiByteSize := 8);

Both ports udiPort 1 and 2 open with no errors and the write function returns successfully. The read function instead always returns empty string. Moreover if i execute ```

cat /dev/ttyO2 or 4

``` no output is returned as no one is actually writing in that file. I tried to change the udiPort value but ANY value i type gives the same result.
What is the right way to handle two serial devices in parallel in codesys ?? Should i edit the CODESYSControl.cfg file to declare the second port too ? if yes, how ?

Thank you.

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