Transaction group and scan class

I have a transaction group that is in OPC >> DB mode.
The items are all SQL tags with a scan class of 1 second.
I am executing the Group with another SQL tag trigger at the same scan class.
Sometimes I am not reading what is in the PLC from these tags quickly enough for them to be accurate I’m guessing because my scan classes are too slow.
I believe the fix is to change my group items to OPC items which will forgo the scan classes are simply pull the data directly from the pLC when my trigger goes off…
Is this the correct idea?
I’m wondering about how accurate this data seems when it appears to be “waiting” to display a value for the full execution time which I have set to 15 seconds…

Try using OPC items in the group and setting the OPC Data Mode to ‘Read’ instead of ‘Subscribe’.

Kevin’s correct. If I understand your question about it “waiting”, you have to remember that the group only locks in values of the opc items when it actually runs. So if your group is set to 15 second rate, you might not see a change in the displayed value for that long.

(Side note: this reminds me of a very old feature request that I’d still like to do: introduce a separate “last scan” value column vs. “current/live” value column)

Regards,