Tag Value Change Event Issue

Ignition
1

I've recently ran into an issue where a tag script (value changed) is triggering when I didn't expect. I have a simple script that stores the value of the tag, along with a couple other pieces of relevant info, into a database for a report. It seems that the script is running when the quality of the tag changes from 192 to 202 but the value has remained the same. I had assumed the quality changes would only activate under the quality change script and wouldn't effect the value change script. Or is there something else I'm missing?

I am trying to figure out why I'm getting the 202 value at all. I looked it up and it says it represents good data that is being sampled slower than requested due to a resource limitation. However I don't have access to the PLC another team handles that.

2

I think you should be able to check the tag's quality and exit the script if isGood is false.

3

The issue is that the value is 0 and I'm getting a tag event for quality when it changes to 202 then another when it changes back to 192. I don't want either of these events because the value still hasn't changed from 0. I know I can check the previousValue.value vs currentValue.value, but I'm more wondering if this is working as intended as the value isn't changing or if I'm missing something else.

4

In version 8.1.31 it explicitly states that the script triggers on value or quality. Seems like this is the intended behavior.

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5

I didn't notice that. I was going off Tag Event Scripts - Ignition User Manual 8.1 - Ignition Documentation where it states just the value. I'll update my scripts to include a check if the previous value doesn't equal the current. Thanks.

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