I have an expression tag that needs to be recalculated once per second. The expression is very simple (adds the value of another memory tag).
I am using a fixed rate 1000ms. But recalculation occurs every 15-20 seconds.
Why might this be happening? What else affects the recalculation period?
Memory and CPU are used by 20%
Thanks in advance/
Possibly other tags in the scan class/tag group are stalling the rest. (What version of Ignition?) Tags use a thread pool to manage multiple tasks, so it is possible to stall, especially with tag events that execute long-running code.
Consider making a tag group just for this item. Also consider using a gateway timer script to do this instead of an expression.
Expression tag value execution with big delay consider less tag group period