Author Topic: Handling "missing tag name" error  (Read 2958 times)

abouhaa

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Handling "missing tag name" error
« on: November 09, 2018, 09:55:26 AM »
Hi,

What is the best way to handle an error of a missing tag name? Assuming I have 5 analogvaluedisplay components each has a different PLC tag name, what happens if somebody deletes the tag on the controllogix PLC side? Right now the whole form freezes until that tag is added back to the tags on the PLC.

I am looking for a way to deal with this error...

Not sure if there are current solutions within the advancedHMI controls/drivers projects but I tried few things and couldn't get it.

Thanks for the help.

Archie

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Re: Handling "missing tag name" error
« Reply #1 on: November 09, 2018, 10:24:56 AM »
I tried this using an AnalogValue display and setting PLCAddressValue to an existing tag. After starting the application, I deleted the tag using RSLogix. Immediately the AnalogValueDisplay changed to "Path Destination Unknown" and the application did not lock up.

Are you using any code in your application, such as a Read method, that could be locking up your application?

abouhaa

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Re: Handling "missing tag name" error
« Reply #2 on: November 09, 2018, 11:08:55 AM »
No I had a complicated program with tons of code but just to test this I created a simple one screen project with 5 analogdisplays and then tried deleting the tag and still getting the same thing.
Do I need to add any data subscribers? I have been looking on the forum and see many uses on the data subscriber; I have never used it and don't know if that is what it is made for...

abouhaa

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Re: Handling "missing tag name" error
« Reply #3 on: November 09, 2018, 11:26:15 AM »
I attached some screenshots... 3 analogdisplays, and 3 tags "DUMMY_PART_COUNT", "DUMMY_PART_COUNT1", "DUMMY_PART_COUNT2".
When I delete "DUMMY_PART_COUNT2" only one of the analogdisplays should display an error and a message invalid path or tag name or no response from PLC...

However in my case all three of them go into error display mode... see screenshot 1.

Thanks.

Archie

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Re: Handling "missing tag name" error
« Reply #4 on: November 09, 2018, 11:35:41 AM »
I just tried the same test, but get a different result.

The No Response error will show in all controls because it means no packet came back from the PLC which is different than a tag that does not exist. Something in your system us causing the communication to get interrupted.

You can run a Wireshark capture and see what is actually happening.

Archie

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Re: Handling "missing tag name" error
« Reply #5 on: November 09, 2018, 11:38:35 AM »
Do I need to add any data subscribers? I have been looking on the forum and see many uses on the data subscriber; I have never used it and don't know if that is what it is made for...
The DataSubcriber is essentially a BasicLabel without a visual part. The data is returned back to an event and code is required to process the values returned. It is designed to make using driver subscriptions easier.

abouhaa

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Re: Handling "missing tag name" error
« Reply #6 on: November 09, 2018, 12:04:39 PM »
Okay so I just found something... Do not stop your advancedhmi application, delete tag then start application again.

What my issue is deleting the tag while the application is running... So start the advancedHMI with 2 or 3 tags, then while it is running, delete one of the tags...

Let me know please.

Archie

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Re: Handling "missing tag name" error
« Reply #7 on: November 09, 2018, 12:20:36 PM »
That is the procedure I used. I did not stop AdvancedHMI. I let it run, changed values of the tags to verify it was showing current values. I then deleted a tag in RSLogix while AdvancedHMI continued to run. As soon as I deleted the tag, AdvancedHMI immediately showed the error Path Destination Unknown only on the AnalogValueDisplay for the tag I deleted.

abouhaa

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Re: Handling "missing tag name" error
« Reply #8 on: November 09, 2018, 01:14:50 PM »
I attached a link to a video of what I am doing..
Please take a peek.

https://www.dropbox.com/s/spale4mn90jq0kx/2018-11-09%2013-07-03.mp4?dl=0

Archie

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Re: Handling "missing tag name" error
« Reply #9 on: November 09, 2018, 02:44:30 PM »
I wonder if this is related to the firmware and controller. I am doing the exact same thing, but using V28 with a CompactLogix.

Can you do a Wireshark capture and post the file?

bachphi

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Re: Handling "missing tag name" error
« Reply #10 on: November 10, 2018, 08:06:09 AM »
What is the best way to handle an error of a missing tag name?
I would create a dummy routine/rung with the all AAHMI tagnames being used, so others cant delete it.

As for comparison, apple to apple, You should try v399y like Archie and I am not clear on whether both used the same BasicLabels or  AnalogValueDisplays.
What version of Studio 5000 being used?
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abouhaa

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Re: Handling "missing tag name" error
« Reply #11 on: November 13, 2018, 08:15:19 AM »
Archie, wire shark capture is attached...

abouhaa

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Re: Handling "missing tag name" error
« Reply #12 on: November 13, 2018, 08:18:41 AM »
bachphi,

I am using Studio 5000 v30.01.
Even if I create a routine with the tags like you suggested, somebody can mistakenly delete the routine and probably the tags later on after noticing these tags are not being used...
Funny things happen all the time.

abouhaa

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Re: Handling "missing tag name" error
« Reply #13 on: November 13, 2018, 09:16:16 AM »
What is the best way to migrate my current 3.99x based forms to 3.99y to try resolving this issue?

Archie

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Re: Handling "missing tag name" error
« Reply #14 on: November 13, 2018, 09:25:27 AM »
Archie, wire shark capture is attached...
Did you delete one of the variables while running the packet capture? From what I see the 3 variables are still reading successfully at the end of the capture file.