Experimental Physics and
Industrial Control System

Mark Rivers via Tech-talk <tech-talk at aps.anl.gov> · Tue, 6 Apr 2021 13:51:05 +0000

Hi Jakub,

> I know there is external software I could use to create a virtual serial device from an ethernet connection, but is there a way to do this from within EPICS?

I don't know of a way to do that inside EPICS.

Moxa provides a "Real TTY" Linux driver that allows creating ports like /dev/ttyr00 to the Moxa device.  These provide all of the serial port controls (baud, parity, etc.).

https://www.moxa.com.cn/getmedia/6fbafa79-1113-4953-a6cc-bef28dae1180/moxa-real-tty-driver-for-nport-tech-note-v1.0.pdf

Mark

________________________________
From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Wlodek, Jakub via Tech-talk <tech-talk at aps.anl.gov>
Sent: Tuesday, April 6, 2021 8:34 AM
To: tech-talk at aps.anl.gov
Subject: Handling Ethernet-to-Serial Connection when vendor SDK expects tty device

Good morning EPICS community,

I had the following question regarding one of the devices that I am currently working on supporting. Essentially, I am using an asynPortDriver
based driver integrated with the device vendor SDK. The vendor SDK has a connection function that expects a string representing either identification
for the USB device to communicate over the USB bus (this I have working fine), or a TTY serial device for communicating over serial (ex. /dev/ttyS0, COM1 on Windows).
When connected directly to the serial port of the target machine, the device connects and this works OK.

However, ideally, we would prefer to use a MOXA ethernet-to-serial adapter to talk to the device, and I am not sure what the best approach for this is. Traditionally,
for say a StreamDevice IOC I would use drvAsynIPPortConfigure(), and then configure the MOXA to communicate via serial on the other end, but given that
the device needs a serial device to connect, I wasn't sure how to handle that. I know there is external software I could use to create a virtual serial device from
an ethernet connection, but is there a way to do this from within EPICS?

Thanks,
Jakub

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System