Dennis Stickles

Creating a tag group

5 posts in this topic

When creating a tag group, what is (Me.AreaName, 250) defining in the code snippet below?

If rpOneTagGroup Is Nothing Then
        Set rpOneTagGroup = Application.CreateTagGroup(Me.AreaName, 250)
        Call LoadSiloTagGroup(xSilos)
    End If


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Under "Me" as a controller tag should be a sub-group called "AreaName" with 250 bytes in it.


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Here's the reply I got from another forum:

" It's been a little while, but I believe that 250 is referring to the poll rate (in milliseconds) of the tag group (how often it checks to see if they've changed)."

There has to be documentation somewhere on this. Does anyone know where? I've Googled it and I've downloaded a bunch of manuals from AB's website and can't find anything. :shrug:

Edited by Dennis Stickles

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To be honest, I've never seen ANY documentation on command line. Its almost as if they are FORCING you to take their course on command line logic. Pain in the butt and wallet.

I don't understand why anything would try to modify its poll rate.

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Well, that makes sense why I can't find anything...

Here's another answer I received to my question that's very informative and I think is what I'm going to go with for now. I may try a test program and see if I can prove out the poll rate.


CreateTagGroup method
Example code

Creates a new instance of the TagGroup collection and passes it back to the caller.


Application.CreateTagGroup ([HomeAreaName], [UpdateRate])


Application – is the name of a FactoryTalk View SE Client Application object or an expression that evaluates to a FactoryTalk View SE Client Application object.

HomeAreaName – is the name of the home area of the display in which the TagGroup is to be created.

UpdateRate – is an optional parameter that specifies the update rate in milliseconds at which the change events for Value, Timestamp, or Quality are returned. Updates for the group will be no faster than this value but may be slower if the server cannot provide the data at the requested rate. The default update rate is 1000.


If the tag group cannot be created, the method returns Nothing, and the error tagErrorUnabletoCreateGroup is raised. The Description property of the Error object might contain additional information about the cause of the failure.
The minimum value of the UpdateRate property is 250. If an attempt is made to write a value less than this to the property, a run-time error is raised and this message is displayed: Unable to set UpdateRate. Value is invalid.
If a negative value is written to the UpdateRate property, the error tagErrorUpdateRate is raised.



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