Hello to all,
I have the Raspian PI4 and I have the problem of modbus communication with CH341 via USB.
The port between Putty and the Hercules software you need to test modbus communication works because I can send a string so the problem is some CODESYS setting.
Reading on the forums I found to add on

CODESYSControl_User.cfg
[SysCom]
Linux.Devicefile = / dev / ttyUSB

But as in the attached picture it doesn't start,
Can anyone answer me?
Edwin, do you have any information for me?
Thanks

Hi,

without these spaces it might work ( and it should be 3.5SP15 at least ->version)
[SysCom]Linux.Devicefile=/dev/ttyUSB

BR
Edwin

Hello and thanks for the reply,
I tried without spaces but still nothing, I tried to modify sudo nano /etc/CODESYSControl_User.cfg as in the attached file putting ttyUSB instead of ttyS and adding
portname: = COM.SysCom.SYS_COMPORT1
but still nothing, I have to maybe sudo nano /etc/CODESYSControl.cfg?
I also set the speed to 115200 by default.
I have to put ttyUSB in sudo nano /CODESYSControl_User.cfg
so without etc?
If someone kindly helps me or maybe Edwin can help me?
Thanks

Hi,
setting is ok,
and from first screenshot I would say comports works.
I would suggest to add the name of the serial modbus device to a watch window to have more information what happens...
(add Modbus_Slave_Com_port to the watch window and undfold it to see more infommation/diag there)
BR
Edwin

Hi Edwin, I thank you for your kindness in answering me,
I have attached to you what happens in the WATCH table, but I ask you, these lines:

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

I have to add them up
sudo nano /etc/CODESYSControl.cfg
or
sudo nano /etc/CODESYSControl_User.cfg
I have to put it
portnum: = COM.SysCom.SYS_COMPORT1;
on CODESYSControl_User.cfg and not on CODESYSControl.cfg
and the speed that I find on etc / CODESYSControl_User.cfg I have to leave to 115200 even if in the forum they speak of 9600?
I ask you all these questions because I have now moved them but the communication does not start.
I state that sending a string from Hercules with Putty the string is received so it must be a problem in the settings.
Thanks for your kindness.

Hi,
you just need:
in /etc/CODESYSControl_User.cfg

[SysCom]
Linux.Devicefile=/dev/ttyUSB

nothing else... if this section is in /etc/CODESYSControl.cfg this will be lost on every runtime update... so the correct place to have is /etc/CODESYSControl_User.cfg.

According the watch window.
"Undefined" means there is no real or proper response from the slave..!

BR
Edwin

Hi Edwin and thanks for the help,
in the attached file I see that the baudrate is set to 115200, on all the examples the tests are with 9600, do I have to change the speed on the file?
Do you think the screen I have attached to you is correct and do I have to set the slaves to 115200?
I ask because I made a thousand changes on the slave and also on the software to try communication from the PC but does not want to leave and honestly I do not know what else to try.

Hi,
you need to change the baudrate here:

remove the ';' infront of: Linux.Devicefile=/dev/ttyUSB
BR
Edwin

Hello,
Without ; as you see in the attachment, it remains with the red triangle, it connects only if I put it and it becomes a green triangle

Hi and thanks Edwin for the kindness in answering me,
now without the symbol; I managed to do what you see in the attached image, but values that are indecipherable appear, if I change a value, something happens in the registers but the indecipherable values change.
Thank you for your kindness

Hi, I've changed the simulator and this works
Thanks for the answers.