Raspberry PI Open PLC

[kevilay]

Hello!

I have seen some stuff with people using a raspberry pi running some sort of open PLC software to run some test examples. Has anyone actually tried this in a real world example on an automation machine? I am curious if you were able to interface with EIP devices? What kind of experiences have you had?

Thanks,
Kevin

 

[JeffKiper]

I had 1 customer that wanted to use them. I wouldn't and walked away from the job. 6 months later I get the call to come rip them out and put in a real industrial hardened PLC. They were having issues with static causing issues with false triggers on the products.

Another integrator I know well said by the time he actually got the application working and talking to an HMI he could have don't 3 other jobs and made way more money.

 

[kevilay]

I had 1 customer that wanted to use them. I wouldn't and walked away from the job. 6 months later I get the call to come rip them out and put in a real industrial hardened PLC. They were having issues with static causing issues with false triggers on the products.

Another integrator I know well said by the time he actually got the application working and talking to an HMI he could have don't 3 other jobs and made way more money.

I do agree with these problems. But the 3 other job argument could be from the lack of experience with the device. I am a python program as well and very fimilar with linux. I do think there are some serious learning curves but PLCs are so expensive now. They are very reliable, but a raspberry PI running linux can be very robust as well. The static could be from not using pull down resistors.

I feel that some good integrations of a more standard roboust IO system could really change the game. I also feel it would be manditory to be able to comminucate via EIP (I don't really see this being an issue as I have written many programs interfacing PLC to Raspberry PI)

What HMI did your buddy use? I would think with a PI I would just use a pyqt5/6 or tkinter library to create an HMI with a standard monitor.

I am looking to use this thread as an open discussion to see what people think about the process.

 

[JeffKiper]

I'm a PLC guy so I can't even spell python. That was his problem also. I would like to learn python but the hours in the day to get things done and learn new things just aren't there.

The IO was the problem. I ASSuME the pull up or down resistors where needed as well. I just don't see these being industrial hardened yet.

I think he was trying to use a RedLion HMI. Probably with a Modbus TCP connection.

I dont't have a clue what pyqt5/6 is. I don't understand what libraries are either. Like I said I cant even spell python.

 

[kevilay]

I'm a PLC guy so I can't even spell python. That was his problem also. I would like to learn python but the hours in the day to get things done and learn new things just aren't there.

The IO was the problem. I ASSuME the pull up or down resistors where needed as well. I just don't see these being industrial hardened yet.

I think he was trying to use a RedLion HMI. Probably with a Modbus TCP connection.

I dont't have a clue what pyqt5/6 is. I don't understand what libraries are either. Like I said I cant even spell python.

Props to him for getting that working. Without that kind of knowledge I definitely think it would be a serious uphill battle.

I couldnt agree more, the IO is not hardened like what you see in the PLC world right now. But that doesn't mean its not possible

 

[JeffKiper]

I agree once the IO becomes hardened it will open the entire market up. Automation Direct has some Productivity Open Arduino hardware that makes may make things easier.

To be honest I don't know the difference between Arduino and a Rasberry PI.

 

[dmroeder]

To be honest I don't know the difference between Arduino and a Rasberry PI.

Arduino is a microcontroller that runs compiled code, with some built in I/O. Raspberry Pi is a full blown tiny computer with an operating system (Linux), also has some I/O.

 

[JeffKiper]

Arduino is a microcontroller that runs compiled code, with some built in I/O. Raspberry Pi is a full blown tiny computer with an operating system (Linux), also has some I/O.

I guess I need to spend some time learning when to use each of them. That's if I get the time to learn how to use them.

 

[kevilay]

I guess I need to spend some time learning when to use each of them. That's if I get the time to learn how to use them.

I would focus on using a Raspberry PI if you get into anything. An arduino would be very difficult to interface with a PLC and offers little in terms of display. A rasbperry PI is moreless a low end PC that runs linux. Python in my opinion is the ultimate language for automation and motion.

There is a excellent course by Ardit (Python mega Course) on udemy if you are ever interested.

 

[dmroeder]

For clarity Jeff, you don't need a Raspberry Pi to learn python, you can learn on any operating system. If you do end up getting more curious about python, PM me.

 

[Old Man]

Just giving my 2 cents worth.

I use the Raspberry Pi along with "Python" and my Allen Bradley Micro 800 series plc's for everything I need.

The Raspberry Pi and Node Red have a great MQTT Sparkplug B "Node" that I use to get all my "TAGS" back to our Ignition Server.

I love this combination.

 

[Peter Nachtwey]

I have python running on my Mac Book Pro, Dell XPS computer, My R-PI and a Intel NUC. It runs every where but it isn't fast like compiled code unless you use the pre-compiled librarys that were compiled using C. Then there is a little difference except for the time the Python interpreter is executing byte-codes.


Also, VS-Code runs on all those computers.


The problem with the R-PI is that many libraries/programs are not yet available because the CPU is an arm chip.


On the TI website there is a page that tells how to make instrument quality I/O for PLCs. This could be modified for a R-PI too.


https://www.ti.com/lit/ug/tidu392/t...06120&ref_url=https%3A%2F%2Fduckduckgo.com%2F


I saw this years ago but did nothing because of the parts shortage.

 

[AlfredoQuintero]

I'm a PLC guy so I can't even spell python. That was his problem also. I would like to learn python but the hours in the day to get things done and learn new things just aren't there.

Jeff, I feel very much the same way. For that reason I would also not quote any job in Python to any customer. I would offer more off-the-shelf solutions.

The CODESYS runtime license is in the neighborhood of US$ 100. If you use an industrial grade RaspberryPI, of which there are some I believe, which work on 24 VDC as opposed to 5 VDC as consumer-grade RasPi do, then I think much of the noise issues are gone. I am not a machine builder. We develop firmware for field devices. Many of my customers who want to add EtherNet/IP functionality do not have a PLC and I recommend them RevolutionPi for their develoment and their quality control equipment for their own final product.
There are other devices such as Exor's touch panel devices that run the CODESYS PLC engine and give you in addition the graphic user interface, which is very good for small machines.
EtherNet/IP scanner functionality is very well supported by CODESYS, the GUI is excellent and the diagnostics is superb. If you configure something incorrectly you get the connection manager extended status from the device in the Engineering tool. The license for the engineering tool is free of charge. It also supports EtherCAT, Profinet and Motdbus TCP.
For an additional US$ 40 or so it can be an adapter and thus you can communicate the CODESYS with a Rockwell PLC by IO messaging. or you can write some code to access Rockwell PLC tags by CIP client messaging.

Finally, end users may be OK with open source. But at least here OEMs do not like the terms of open source licensing, so this is another thing to look into if you are considering open source solutions.

I think these solutions for the "PLC-kind-of-guy" I think myself of are so easy to use and reliable, at least for small machines. Fancy stuff such as QuickConnect is not supported. You would need Python and dmroeder's library for that kind of functionality. Anyways, just my two cents here.

 

[Old Man]

I think we should be prepared for what the future holds.

https://www.onlogic.com/computers/i...ccwFMPtcM9cZ6Zd-QU7NOJxx-QrP1o8xoCFPsQAvD_BwE

 

[theColonel26]

I think we should be prepared for what the future holds.

https://www.onlogic.com/computers/i...ccwFMPtcM9cZ6Zd-QU7NOJxx-QrP1o8xoCFPsQAvD_BwE

The price for the 1 with IO is Nuts. Almost $900? Wago CC100 is the same price, and more reputable brand.

Might as well go with a RPi Based Panel PC, and use a Click PLC for IO over Ethernet.

That is what I am planing to do for some low end standardized machines.

(With Codesys off course)