How do I control a Beckhoff EtherCAT Coupler with powershell? - powershell

We have a Beckhoff EtherCAT Coupler which is currently being controlled by some c# code, we call that c# code from a powershell script. We want to move the entire process of toggling slots on the coupler to the powershell script but I'm not sure how to do that. If you could provide me even with information on how to send/receive Modbus commands in powershell that would be hugely helpful.
Thank you!
EDIT:
Here is the code used in C# to toggle one slot of the IO coupler:
using System.Net.Sockets;
using Modbus.Device;
TcpClient tcp_connection = new TcpClient(ip, MODBUS_TCP_PORT);
ModbusIpMaster coupler = ModbusIpMaster.CreateIp(tcp_connection);
coupler.WriteSingleRegister(0x1120, 0);
coupler.WriteSingleCoil(slot, state);


Acontis offers an EtherCAT Master for Windows library and a C# example application you could leverage to include into your own application: https://acontis.com/en/ecsta.html


Working with machine automation controllers is highly manufacturer specific. I've got working knowledge only about Omron PLC & MACs, so I cannot provide exact details.
Anyway, one way would be to create a C# DLL and call it from Powershell. As how to program the coupler, start by finding out which model, exactly, you are working with and searching Beckhoff's documentation. Maybe there are suitable samples available.
Consider also contacting manufacturer's support. They might be able to provide advice with very reasonable pricing, unless the task grows into a consulting gig.
Programming PLCs and MACs is often done via manufacturer specific solutions. Those are much simpler to use than general-purpose language such as C#.

Related

Use python instead of Structured Text

I have a Codesys Project which becomes more and more complex.
Now I’m wondering if there is a python library that lets me do the programming part, I’m usually doing with Structured Text via Python?
Thank you
A

If you were using the Beckhoff platform which is very similar to Codesys I would have advised you to look into the ADS interface which helps interface PLC's with user space programs.
For Codesys there is also a proprietary interface called the PLC-Handler but it's not free of cost.
Since you have to pay one way or the other the approach I suggest is to buy the MQTT-Client for Codesys and write a Python-Client with one of the freely available libraries like the one of the eclipse foundatation: https://www.eclipse.org/paho/index.php?page=clients/python/index.php
The advantage of this approach is that once you've written the user space client you can interface with all PLC brands, since every major PLC brand offers an MQTT-Client library which you can use to write a small command and control PLC-Library for your PLC's.

Is it required to use an OPC Server to Communicate with Controllogix?

I'm wondering if for simply communicating with a PLC, like reading and writing tags, do I need all of the other heavy lifting that comes with an OPC-UA server?
I've tried writing a simple server in Python that talks to the PLC, but I get denied when requesting information from the PLC.
The Controllogix PLC I'm attempting to communicate with uses Ethernet/IP to communicate, so why doesn't a simple server/client script work? What is required exactly to communicate with an Allen Bradley PLC or PLC's in general?

There is quite a bit required to communicate with a PLC.
Each vendor has a driver, there are firmware compatibility considerations. Different protocols to think about.
OPC-UA makes it a bit more generic, but OPC-UA still has a set of things to work around when setting up communications.
Most of the OPC products I've worked with, needs to have their security adjusted to allow anonymous communication. It's generally bad practice to do this. (A network intrusion would be able to read/write to your automation layer) There is certificate signing and some encryption business that needs to be turned off if you're looking for simple communication. (Again, not a good practice but ok for learning)
After all that you have to have a notion of how your PLC is set up on your OPC server, there are channels, devices, namespaces etc. You'll point the OPC client to some opc.tcp://:
If you got this far you're almost done, I'm assuming your OPC server is running and has tags configured at this point. You can use your OPC-UA API to do a read. It can return just the value, or you can get an object back with tag health, timestamp, and a bunch of other data. Depends on the implementation. After that you can do subscriptions, writes...whatever else you need.
TLDR: OPC server not required, but may be the easiest method. Turn off security. (But turn it back on before exposing your control layer to the net)

I am also a little late to this conversation. If you are interested in coding your own solutions and don't want to use any of the commercially available standards, AdvancedHMI is a "mostly" open source solution written in VB.NET which is 100% free and provides communications to many different PLCs including the ControlLogix platform. Since I see you are programming in Python you may also be interested to know that the project does work under Mono on the Linux OS. I have used it to write gateways between EthernetIP and ModbusTCP and to pull data serially from OEM devices and push this data to a CLX PLC.
The forum is full of many helpful hints and is very active and supported.
Just trying to give you another option. DDE, NetDDE, FastDDE, OPC, DCOM, Suitelink.... These are all good, but mostly a pay to play adventure. As a programmer, it seems ridiculous to have to pay such an excessive amount of money just to talk to my hardware, IMHO. Sorry for the rant. Have Fun!
Update - Just wanted to also suggest the following open source project written in python:
https://github.com/dmroeder/pylogix
I have used this to write small programs for communicating with CompactLogix and ControlLogix. (Even to/from a RaspberryPi!)

Depends on several factors, if you want something simple to program you can opt for Modbus/TCP I think some AB PLC supports it without extra hardware.
However if you want something with more security for example for industrial use then OPC UA would be better choice but the programming has a complexity far higher than Modbus, even using the libraries of OPC Foundation or others. There is the option of using a commercial or free (if any) OPC UA server to save work, then you will need to program the client side only.
With Ethernet/IP it should also be possible, but the problem is that there is no clear specification and even different AB models talk different Ethernet/IP dialect ! , it is also far more complex to program than Modbus.

I am a little late to this discussion, but there are a couple commercial tools that make this a bit easier. The one that comes to mind for me when you say you are using python is Cogent's data hub. It is certainly not the cheapest tool out there, but they have already done all of the heavy lifting for PLC/PC communications & security.

If trying to read CLX data using Python, there are several open source implementations that will save you a lot of work. Such as this:
https://github.com/dmroeder/pylogix
If you use .NET and Visual Studio, you can use AdvancedHMI

to be able to read and write OPC Tags to ControlLogix platform is done via its communication Driver RSLinx. RSLinx acts as an OPC Server, it will need to be configured to communicate with the PLC and run on a networked PC on the same LAN. Several flavours of RSLinx are available (for WAN/VLAN also) but essentially this is the communications driver you need to talk to AB PLC's

Process/ Work Flow Engine

I am working on a solution for which I need a work flow/process flow engine. My work flow contains some Java based processes(classes) and some Linux Shell scripts. The flow would not be static and the execution of each process depends on the state/outcome of the previous process, and there would be multiple paths and the path would be determined the state of the previous processes.
I tried looking at jBPM, but I do not find a suitable support for invoking shell scripts. Please suggest me a suitable alternative for my requirement.
Many thanks.

well you can use jBPM5, it's extremely simple to add support for running shell scripts, we can help you with that.
Can you elaborate a little bit more on the requirements that you have?
Cheers

Interprocess communication in windows xp

I have least knowledge on network domain.Please bare with my question if it is basic
I would like to know how to communicate between two applications using TCP/ip protocol in
windows XP say for example
Using Perl and TK I am building a GUI with entry widget and i have an other external application which is installed in the system say APPLICATION.exe
Now i need to establish the connection using TCP between my perl program and external application APPLICATION.exe
for testing purpose what ever I type in the GUI Entry this external application has to receive (hope it receives as bytes)and external application will send some data and i need to process that data in my perl program..
I am totally unaware whether this is simple task or complicated.
If there are any modules existing in perl for similar programming please suggest me.
I highly appreciate if anyone can provide me the answer with an example.
Thanks to all

It is simple if you have done network programming before. If not, it is intermediately difficult because you need to get a grip on the underlying concepts and terminology first - read a book about the topic if necessary.
I recommend to use IO::Socket::IP. If you have Perl 5.14 or later, you can also use IO::Socket::INET that is distributed with Perl. See https://stackoverflow.com/a/8582550/46395 for a code example and links to further documentation.

Any good library or software for queue networks simulation?

I have been trying to make work EZSIM with no luck, which is a software to build discrete event simulators in a graphical DOS environment. In this software, my simulator and many others (of the other people in the course I'm taking) don't work, but teacher's simulator (and examples of the downloaded files) does work.
So, I began to distrust of the software.
Do you know any software that resolves the same kind of problems but really works? It will be good if it is free, or I can download an evaluation copy or something like that.
If you don't know any software, do you know any library which might work? Preferably in C#, Ansi C, Java or Delphi.

This may be more than what you're looking for, but check out NS2. It's the standard for open source network simulations, and will allow you to simulate all kinds of network layer behavior.
I've also used JUNG in the past. It's very flexible, although it also doesn't offer much out of the box.

I used Möbius in my computer systems analysis class. It is free for educational use (which sounds like what you're doing). It's a Java GUI which generates C++ code.

The R package queuecomputer. queuecomputer is a computationally efficient method for simulating queues with arbitrary arrival and service times. There is a submitted paper on arXiv describing the algorithm used in the package. Examples can be found within the arXiv paper and the vignette. A web app based on the package is available at https://ace-ebert.shinyapps.io/queue_simulator_mmk/ .