Sorry, it’s me again with another problem.
I have an random problem with a transaction group missing triggers. Unfortunately i have not been able to reliable reproduce the issue, so i try to describe what happens:
The transaction has a ‘active on value change’ trigger. The same opc tag that is used for the trigger is used a second time in the group to log a converted value.
When the driver updates the subscription, the trigger value is sometimes one execution cycle behind the other values.
Here is a log that shows what happens:
At this point, the transaction group has executed the first time with ‘null’ as teh trigger value. The driver has been updating the subscription twice before.
In the DB, the logged trigger value is also null, but the second value that uses the same tag logged the correct value.
Here the transaction group executed the second time. This time the trigger tag has the correct value, but the group was not triggered. I would have expected an execution here, because the trigger changed from null to 1365013573276. It looks like the value stored after the first execution for the ‘on change’ comparison is not the value that actually triggered the first execution.
If the subscribed values had changed between the first and the second execution, i would have lost the record completely. To prevent this, i have the execution rate of the group set to 3 times the minimal data change rate.