EtherCAT basic project

[Sam Dexter]

We've just got an ABB EtherCAT communication module for ACS880 - FECA-01 and were absolutely sure we won't have any problems creating a LabVIEW control application for it. However, we got stuck from the very beginning. We found practically no examples or instructions on how to create an EtherCAT application from scratch. There are a few examples, mostly related to setting up a project with NI-9144 or similar, but nothing for a custom EtherCAT slave device.

I am curious if anyone could provide me with any pointers as to how to set up a project for FECA-01 or point me in the right direction.

Thank you in advance.

 

[Antoine Chalons]

i can't really answer your question but I suggest you watch this presentation : 

 

 

[Rolf Kalbermatter]

NI was quite invested in EtherCAT circa 2012 to 2016 but then lost its interest in anything not related to big turnkey testing systems. The Industrial Communication tools were part of that together with Motion, Vision and pretty much anything else except DAQ and PXI.

Basically EtherCAT after about LabVIEW 2017 is more of a "Take it as it is! If it works for you, great! If it doesn't, please don't bother us!" Even in LabVIEW 2017 it was still far from a Plug and Play experience. I worked on a project at that time, trying to interface a Industrial Controller IC-3173 to several different EtherCAT hardware. It was a long and tedious process and back then we could actually talk to support people who tried to help but often were stumped just as much as we, why something didn't work. There were many subtleties and it was not always NIs fault when something didn't work, but it was very difficult to get a deeper look into things as NI tends to hide a lot behind simple looking configurations.

At this point I have very strong doubts that anyone at NI even knows how any of these Industrial Communication Products work. They still sell a few things that can work if you are lucky, but if it doesn't work, they can't support it in any way, since there simply is nobody anymore who has worked on these products in many years.

The good news is that NI definitely has been getting a lot more proactive on a lot of subjects in the last year. Their efforts to get the community involved again, still need to be fully realized but the communicated intentions are strong and fairly consistent, so I dare to have hope. From some communications I had with them, it seems that they actually are planning to be more concentrated on certain core areas and actively look for 3rd parties in the market to provide alternative solutions for the products they don't consider a core technology. Industrial Communication interfaces seem one such area, where they would seem happy to promote an alternative rather than maintaining their own solution, but they might pick up on some of them, as they are not all as easy to support for 3rd party providers.

 

Edited January 25 by Rolf Kalbermatter

[Sam Dexter]

So, what I dug up so far:

1. Many compactRIO can be set up as an EtherCAT master. You don't need any special hardware for that. In fact, even your laptop Ethernet port can be turned into an EtherCAT master with the proper set of drivers (not covered in this post). Nevertheless, check if your chassis supports EtherCAT mode - go to https://www.ni.com/pdf/manuals/374786m.html and see if it listed under Supported EtherCAT Masters.

2. Download EtherCAT drivers here -  https://www.ni.com/en/support/downloads/drivers/download.ni-industrial-communications-for-ethercat.html#485587. First, check your LabVIEW compatibility with the EtherCAT drivers here - https://www.ni.com/en/support/documentation/compatibility/17/ni-industrial-communications-for-ethercat-and-labview-compatibil.html. Install the drivers to compactRIO under Custom Software Installation. Configure one of the Ethernet ports as EtherCAT master.

[Sam Dexter]

NI article:

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YHbbCAG&l=en-CA

 

[Sam Dexter]

Setting up the project:

 

[Sam Dexter]

A peculiar thing about the EtherCAT slaves is that you must have an ESI (EtherCAT Slave Information) file for your slave. This is an XML file that describes the EtherCAT specifics and application specific features of the device. Those are available form the device manufacturer's site, e.g. https://new.abb.com/drives/connectivity/fieldbus-connectivity/ethercat/ethercat-feca-01.

If you cannot get an OEM's XML file for your device, you can (theoretically, I've never done it myself) edit one of the existing files (or create a new one) either manually or with a help of special ESI Editors (cost money and, usually, manufacturer-specific). E.g. https://github.com/CopleyControlsOfficial/EtherCAT-ESI-File-Examples.

[Sam Dexter]

This is by no means a full EtherCAT tutorial but, rather, introductory notes. Please, feel free to add to this post, expend and/or correct any mistakes and information.

[Michael Aivaliotis]

I have worked extensively with several of my customers with Ethercat devices using the NI solution. I'm glad you figured it out. It seems like you're on your way. Finding the ESI file is the trick and making sure it's "installed" on the cRIO and the PC side. To echo what Rolf mentioned. You will get very little support from NI if things go wrong, or if you want to do something that is outside of the typical use-cases.

Note: you have zero control over the topology of the Ethercat network. NI hides this network discovery algorithm, and you cannot influence it. This comes up when you have more than one device on the network and/or you have Ethercat switches in the mix. For example, if you daisy chain another device it will be named device 1 (in your image, your first one is named "device"). If you swap the devices in the chain, they will also swap position and hence, names and you cannot control this behavior. In other words, the physical network cabling dictates the device list order and naming you see in your project. This might not affect you, in your case, but something to be aware of. Especially since your shared variables will be invalidated.

Personally, I don't use statically defined shared variables because I typically work with highly dynamic systems. But using your approach will work just fine and is the easiest way to get started. There is a way, to dynamically discover devices on the Ethercat bus. Here is an NI article describing this: Programmatically Discover and Access EtherCAT I/O Items - NI This might be useful and good to know in case you need this approach.

[Sam Dexter]

Thank you Michael. Good point.

Yes, I've noticed the dynamic approach here and there as well as using SoftMotion with EtherCAT but had no chance to dive in yet.

I will take a look at the other methods later this year when we start working with ELMO (Platinum) drives.

Edited February 2 by Sam Dexter