Serial Console

PLCnext Technology & PLCnext Controls
1

Hi,

If we are adding AXL F RS UNI 1H card to AXC F 2152, ttyS (serial console) option will be available or not?

  1. If it is available then which serial console it will take, how to find out?
    Since the PLC /dev is having too many tty’s by default
    #attached

  2. should we need to map external hardware with any of the serial console for avail this option?
    Then what is the procedure for that?

If the ttyS (serial console) option is not available then how to change the parameter of AXL F RS UNI card using python script?

2

Hi Sarath,

If we are adding AXL F RS UNI 1H card to AXC F 2152, ttyS (serial console) option will be available or not?

Unfortunately, no. Axioline modules exchange I/O (or “process data”) with the Axioline controller, but the serial port does not get mapped to a tty device in the OS. In future it may be possible to use the USB port on the CPU as a tty device, but we don’t have a timeline for this yet. But even then, it may not be possible to configure Axioline modules directly through the USB port.

If the ttyS (serial console) option is not available then how to change the parameter of AXL F RS UNI card using python script?

Your python script would need to use the Acyclic Communication RSC service to set the serial port parameters. To do this, it must be possible for python to use a C++ shared-object library … which I think might be possible using a binding generator? I can check with our python expert here if we have any examples of how to do this. One question from me - after configuration, what type of application on the PLCnext Control is sending and/or receiving serial data through the Axioline serial module? Is it a PLCnext Engineer application, or some other type of application? It may be easier to update the Serial port configuration from inside that application, and then just pass the serial port parameters into that application from your python script. ~ Martin.

3

Hi Martin,

Our application is to communicate with RS485 devices.

Currently we are using pyModbus library in PLC next for the communication of Modbus TCP and its working fine. In the same library there is an option to map the ttys for the RS485 communication. In our application we need to change the Function Codes, No. of devices and registers directly from the python because the remaining logic is based on that.

4

Ok, I think I understand. It seems that what is needed in this case is a Linux device driver for the AXC serial module. This does not exist yet (as far as I am aware) but it would be an interesting exercise to create this. I guess that most applications on a PLCnext Control would access the Serial port using Axioline process data, but of course this is a proprietary interface that a general-purpose library like pyModbus would know nothing about.