[FEATURE REQUEST] support tag enumeration

[spike0xff]

I'm not very familiar with Ethernet/IP, CIP, etc. but I know that some Rockwell/AB PLCs can enumerate - send a list of - all the tags that are available, along with some information about each tag. I know rslinx can do this. I'd like my stand-alone applications to be able to do it too.

Current Behavior

Expected Behavior

Seems like this would be a new Controller method that actively enumerates tags (maybe with some filtering options) and returns an array or object representing a tag collection.
In the simplest case, after connecting to a PLC, you'd call getTagList or getSymbolList(options) - it would return an object similar to a TagGroup but with more info per tag.

Possible Solution (Optional)

Would be very happy to contribute code, if I can figure out the code and how to integrate it.

Context

My company uses relatively lightweight edge devices running either Windows or Linux, and we distribute these to multiple customers. We encounter a variety of PLCs running a wide variety of programs, some well documented, some not at all. We prefer not to go on-site if we don't have to, and we don't want a complex or labor intensive setup process. I'd prefer not to rely on (or install) bulky or platform-dependent tools (not naming names but rslinx and CCW).
I want the ability to 'browse' a PLC in the field with platform-independent node code, automatically, given only its IP address.

Your Environment

• Operating System and version: Windows 7 and 10, Linux (stripped down Ubuntu).
• Controller Type (eg 1756-L83E/B): multiple, but often 1769's

[jhenson29]

cmseaton42 was working on this as of around 3 weeks ago, but I don’t know what the status is. It’s also going to require finishing some additional items like UDT read/write (I’m currently working on, or was before I went on vacation this week) and fragmented read/writes. There’s a “manuals” folder in the project with info (specifically the two data access PDFs).

[cmseaton42]

I am working on this now! Sorry for the delay :). More to follow as progress is made!

[spike0xff]

Hey that is awesome news, I hope to be in a position to work on ethernet-ip later in October! I can help with testing at least ;-)

[JollyWizard]

libplctag has an example in c that looks like it covers most of the details.

https://github.com/kyle-github/libplctag/blob/master/src/examples/list_tags.c.

[SerafinTech]

Over a year since last update on this feature. I added support for this in my fork.

https://github.com/SerafinTech/node-ethernet-ip

Enjoy!

[kyle-github]

If you are using my code for examples, I recently added support for listing program tags too. For other examples, please look at D.M Roeder's pylogix. That's where I learned how to do it!

[klmurphy72]

@SerafinTech ,

I am using your addition to the library successfully! It is awesome. I'm using it to pull all the tag data structure out and then search for instances of AOI's. I then set internal tags of the AOI's. This is a "name" tag that is the name of the enclosing tag. This provides an Id that is provided externally instead of writing ladder logic to fill in the field. A MAJOR time-saver!!

I see that you have added the ability to read / write string tags. It does work, but not with user defined strings. Is this to be expected?

Ken

[SerafinTech]

@klmurphy72 ,

Here is a link to the first youtube video that I made to show how to use the library. It shows how to read strings. To write a string just set the tag.value = 'string' and then PLC.writeTag(tag). I still need to update the README.

Jason

[mataherry]

Over a year since last update on this feature. I added support for this in my fork.

https://github.com/SerafinTech/node-ethernet-ip

Enjoy!

@SerafinTech is it possible to publish your palette to node-red repo :)?