Expression tags not updating

General Discussion
1

Hi All,

I'm currently having trouble with Expression tags. These are the settings that I currently have:

1
1551×506 6.71 KB

The tag in the expression updates pretty fast, however the expression tag itself updates very slowly. I've also tried changing the Execution Mode to 'Event Driven' but the rate at which it updates is still slow.

Any help would be appreciated!

2

Can you get a thread dump from the Gateway and upload it here?

https://docs.inductiveautomation.com/display/DOC81/Diagnostics+-+Threads#DiagnosticsThreads-IndividualThreads

3

Thanks Kevin,

Here's the downloaded thread dump
Ignition_thread_dump20231006-163336.json (632.9 KB)

4

Expressions execute in a limited size thread pool, and it looks like all of your expressions are busy executing Python scripting that you've invoked via runScript. These need to be used sparingly and execute quickly so they don't affect other parts of the system like this.

5

Thanks for the feedback Kevin.
Is there a way to increased the size of the thread pool? I have another project that uses the exact same scripts, but don't run into this issue.

I disabled the UDTs that used runScript in the expression, however the updates were still slow.

6

There's no need for an expression in the example you've posted.
Expression: -1 * {[.]34_5 kVAR raw}
You're just multiplying by -1.

Use the scaling feature instead.

Value Source:     OPC
etc.
Scale mode:       Linear
Raw Low:          0.0
Raw High:         100.0
Scaled Low:       0.0
Scaled High:      -100.0