I have a large number of tags in a PLC that get updated
at one time in the PLC. Then I want to tell Ignition to come
get all of them using a BOOLEAN tag in the PLC set to True.
All tags are in the same tag group, at a rate of 1000ms
I have a gateway tag change event with the boolean tag in it.
When the event fires and I see that the tag is TRUE, I write
all those tags to a database. That is all working just fine.
SOMETIMES the values of a few of the tags have “stale” data in them from the previous
time they were refreshed in the PLC a few minutes ago.
The PLC only refreshes the data every few minutes.
How can I know that the tags have the most recent data in them from the PLC?
In the gateway tag change event script, I want to be able
to somehow tell Ignition to refresh these tags.
THEN I will write them to the database.
So I was thinking in my gateway tag change event
to use: system.tag.requestGroupExecution()
However I don’t know if it is synchronous or not?
If it is asynchronous then it will not help me.