Serial Port Emulator

wvjason · Sep 12, 2016

Hi,

While this is not directly a PLC question, it would be helpful for me to get some suggestions. I am doing development in the office where I have a PLC (logix) and HMI. One part of the project is to read/write data to/from the PLC. I won't be able to test the link until commissioning and I'd like to get as far as I can in the mean-time.

Any suggestions on a good "serial emulator" I have used similar things for Modbus.

Thanks

harryting · Sep 12, 2016

Elaborate a bit. I'm not understanding the function of a serial emulator in your test environment. You already got the PLC and HMI so what do you need the serial port emulator for?

wvjason · Sep 12, 2016

I will have a very old dew-point meter that talks 232 to the PLC (constant data stream) and an even older RTU which passes data to the PLC. The RTU requires hand-shaking after it sends the data. I am looking for something to emulate/simulate these devices. I wanted to test my PLC logic. I haven't done any serial comms with AB Logix and would like to have some general confidence it'll work. Thanks

widelto · Sep 12, 2016

Do you mean a usb to serial converter ??

wvjason · Sep 12, 2016

Sort of....in my last project I had a laptop setup running a ModScan Modbus simulator where I put simulated data at Modbus addresses. The laptop sat on my network and showed up as a master or slave to the PLC allowing me to test my comms without having the actual Modbus master or slave available.

harryting · Sep 12, 2016

You can always get use any PC with serial port or USB-to-serial running a terminal program to simulate a serial device.

wvjason · Sep 12, 2016

Can you describe how to do that windows 10? Its been so long since I've had to use "grandmas" RS-232... I think the last time I used regular old RS-232 was to communicate with a SLC because the Ethernet port died.

Thanks... great idea.

anthr_plcnewbie · Sep 12, 2016

harryting said:
You can always get use any PC with serial port or USB-to-serial running a terminal program to simulate a serial device.

I am just curious, wouldn't he need to connect to a real device using the USB-to-serial adapter? If yes, how is this 'simulating' a device? If not, then I don't understand how it will simulate using an adapter? Thanks!

wvjason · Sep 12, 2016

I have a spare PC with a USB-Serial adapter I could use. There is virtual software which simulates the device and puts data out through the com port available, but I have not used it and was hoping someone could suggest something for any option. I've done the same thing with Modbus a bunch of times. Thanks

bjh · Sep 12, 2016

This software from Eltima called Virtual Serial Port Driver has a free 14 day trial and is worth every penny should you pay for it. I think it is exactly what you want. I use it to talk to RSEmulate 500 with AdvancedHMI.

It only emulates the port, you have to provide the serial data to the port that you want. It's very simple and easy to use too.

http://www.eltima.com/products/vspdxp/

Epy · Sep 12, 2016

wvjason said:
I have a spare PC with a USB-Serial adapter I could use. There is virtual software which simulates the device and puts data out through the com port available, but I have not used it and was hoping someone could suggest something for any option. I've done the same thing with Modbus a bunch of times. Thanks

Not sure I'm getting this right, you have a simulator program for your device but you don't want to use it?

If it were me, I'd make a Python script to respond to serial port requests. Python is a pretty simple and straightforward computer programming language if you're unfamiliar. I've used it in the past to sniff Modbus signals across a line, and to query flow rates from a Sierra thermal mass meter (has its own protocol).

Ken Roach · Sep 12, 2016

So the Logic device is real hardware, but you want to simulate serial devices in the field. Is that correct ?

A flexible and powerful tool you might look at is Realterm.

http://realterm.sourceforge.net

If you want to have a true hardware box that can emulate lots of serial protocols, buy a Red Lion DataStation Plus. Mine sees duty as a serial slave tester all the time.

wvjason · Sep 13, 2016

BJH and Ken ... Thank you... that's exactly what I was looking to find. Epy ... I'll take a look into python at some point. It's not something I'm familiar with.

Thanks all for the help!!!!

Serial Port Emulator

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