Hi ,
In Transaction group Latch Value is not coming same as Source value.
Quality is Good, not sure why Latch value is not showing same as Source.
Please advise.
thanks
Has your transaction triggered?
yes I have a componentId tag in same transaction group, everytime it changes, i have set it to trigger.
Are your items pointing at Ignition tags or directly at OPC items?
If the former, you might be getting your trigger change before the other items are updated, yielding stale data. You cannot control the order of update of OPC tags in subscriptions.
If the latter, have you set the mode to OPC Read instead of subscribe? If in read mode, the transaction will perform a direct OPC read of the items after the trigger fires, ensuring that your data is captured without races. At least, as long as the PLC changes the trigger last.
so I have a UDT in Ignition tags that it referencing to MQTT Tags.
These UDTs are what I have linked in Transaciton Groups. OPC mode is subscribe. and trigger is set like this..
One weird thing also i noticed is, I used a sql query in script to record data and that also shows 0 for all tag values. I am thinking now if it has to do anything with tags or SQL Bridge. I even restarted SQL bridge module.
Used system.util.logger in my script and i got the values. but during sql transaction its recording as 0.
everything was working fine 2 days ago. nothing changed.
That suggests that it is some aspect of MQTT tags. But key will be the order of arrival of tag updates. I suspect a race.
(You probably should only monitor one tag as your trigger.)
I trigger only one tag. but others are part of the group so they get executed. I had log of 200 of these which worked completely fine 2 days ago.
is this correct?
That's for direction. And MQTT tags aren't OPC tags, so the OPC mode isn't relevant.
You may need a fancier algorithm that briefly waits after a trigger for other tags to settle, then snapshot them all for storage. (Scripted, some combination of tag change and timer events, with a memory tag for state.)
whats weird is.. my other transaction group is just running fine.
