RSLogix5000 - Tag Actively being read by one or more clients

I'm working on a project using a pair of 1756-L62 processors using RSLogix5000 ver 18.02 and FTViewSE 6.00 standalone. The odd thing that is happening is that when I create a tag in the PLC and then later try to delete it, I get this message:

Failed to delete tag "Test".
Tag is actively being read by one or more clients.

The problem is, it shouldn't be. The tag was never used on an RSView screen. What "client" is actively reading it is a mystery. If I create a tag online, and then immediately delete it, it usually works. However, if I leave it for a few hours, it's very likely to be locked down.

Something I noticed while I have FTView Studio open on the same computer is every time I create a tag online, the status window in Studio gets notified. Hmm, makes you wonder.

The workaround I have used so far is to mark tags for deletion by changing their description to delete. Then periodically, I reboot my pc without running FTView and pull the network connection between the PLC and the plant network. (I use a different connection for my pc) After about 90 seconds, I can delete the tags.

Now, I do have a machine running FTTransaction Manager too. And it also reads tags in the PLC, but not the ones I'm trying to delete.

I would like to be able to trace this down to exactly what is "actively reading" my tags, and be able to identify what application is responsible. But I haven't found anyway to access this data. Factory Talk knows it, I just don't know how to get it to share that info with me.

I have this happen often happen to me too. I thingk it's RSLinx Enterprise. It grabs new tags when they're created.

That is such a common problem, it's almost like it FTView/RSLE was designed that way. Your workaround is about the only solution.

The really annoying thing about this is that RS Linx "locks" ALL the PLC tags, not just the tags clients are requesting. It's probably the most annoying thing about RS Linx I've encountered and one of the biggest reasons I push Kepware to my A-B customers.

Anyway, hopefully A-B will get smarter one of these days and change this to a warning with a "Do it anyway" button.

I'd say it's hopeless, but after 13 years of bugging them they are finally making it possible to store the program comments in the PLC with the program, so who knows....

OK so I think I found a solution to this problem. Well it worked for me so here it is. I had a PV1000+ and a Controllogix plc but couldnt access the PLC because of plant policies. Couldnt delete most tags because they were actively being read. (Not really but thats what rslogix 5000 said) I went online with the PLC. I downloaded my ftview .mer to the HMI. WHile the HMI was rebooting from the download, I closed ftview studio. Went to my windows task manager and ended the process rslinxNG.exe. Then went back to RSlogix and I was able to delete over 200 tags that were "actively being read" without stopping production or putting the PLC offline. Hope this helps.

Absolutely, if you shutdown all RSLinx OPC servers which are accessing the PLC, you can delete any unused tags as there's no supervisory system left to keep them locked. But this is a work-around, far from a solution. Getting some of my customers to run blind (with no HMIs) for even a few minutes would be a task itself. Getting others to shutdown their plant-wide data collection system would never happen.

The thing I may be able to do is unplug the PLC from the network and use a cross-over cable (okay, today's laptops don't actually need x-over cables) to connected and delete the tags. It still leaves them blind, but maybe for less time. And yet another work-around for an overly-restrictive software limitation.

This is the best on offer:

https://rockwellautomation.custhelp.com/app/answers/detail/a_id/51691 - How to change a tag data type online?

The Controller limits what can performed while editing online, so the following procedure can be used to accomplish this:
Example: Change a DINT tag to a REAL type tag.
1). Create a new similarly named tag with the data type of REAL.
2). Edit the logic to use the new REAL tag.
3). The DINT tag can then be deleted when it is no longer used by the code and is no longer being read by an external application.
4). Rename the REAL tag to that of what the DINT once was.

https://rockwellautomation.custhelp.com/app/answers/detail/a_id/471161 - Failed to modify properties for the tag. Tag is actively being used.

Question

When renaming tags in a ControlLogix processor the following message appears:Environment

• FactoryTalk View SE v6.1
• The tags in question are not being used as part of the project.
• Other tags in the same controller, same shortcut, are being scanned.

Answer

As a workaround:

1. Stop/start RSLinx Enterprise.
2. Make the edits offline and download to the controller.

Note: If the Logix application is using ControlNet, this will require rescheduling the ControlNet network.
Second possible workaround:

1. Export project to .l5k
2. Import it back to .acd file
3. Download the project to the controller.

As a workaround:

1. Stop/start RSLinx Enterprise.
2. Make the edits offline and download to the controller.

Still NOT a workaround for a plant that run 24/7 with multiple clients.

jkerekes said:

As a workaround:
Still NOT a workaround for a plant that run 24/7 with multiple clients.

Click to expand...

Agreed. It makes you wonder if A-B needs to send their cube-monkeys out to the field for a few years to get an understanding of the real world, or if they are just being overly-cautious by order of the legal department. Maybe what they need is to create a "super user" mode where you can get into all kinds of trouble if you are willing to accept the risks of doing so. Modicon use to have something like that built into Modsoft so the maintenance techs couldn't get into too much trouble, but the engineers could still get their work done.

If anyone else is still having this problem, I found a solution where I did not have to download, or go offline. In the tag database I changed the tags "External Access" from Read/Write to None. I was then able to delete the tags.

Good tip, but this is a new feature and only works with RSLinx Enterprise v5.9 and above (bundled with FTVS v9).

I still can't wrap my head around this thinking, the HMI is the boss?

Go to Monitor Tags.
Right click tag.
Set property from Read/Write to None.
Now you can delete the tag.

sandwich said:

Go to Monitor Tags.
Right click tag.
Set property from Read/Write to None.
Now you can delete the tag.

Click to expand...

Again, this is a newer "feature". If you have older Panelviews/RS Linx you are still unplugging the Ethernet cable.

sandwich said:

Go to Monitor Tags.
Right click tag.
Set property from Read/Write to None.
Now you can delete the tag.

Click to expand...

Thanks! This worked for me.

As a note, right clicking and going in to the properties dialog box to change the access seems to be important. When I just changed the access from the "Edit Tags" list it didn't seem to reset the existing connections. When I changed it through the properties dialog box and clicked "Apply" it seemed to reset the existing connections and let me delete the tag.

-Benaiah

You'll see the same behavior on Proface HMIs. So it's not just FT doing it.