I have a seemingly strange thing happening with a Transaction Group setup. I have a “Master Alarm” bit that, when set on by the PLC should store a list of “Alarm Reason” bits (only once), then when set off by the PLC should store the same list of “Alarm Reason” bits (again only once). I have set the trigger for the group up as shown in the image below. Note that the trigger bit is also stored to the database.
What seems to be happening is that several consecutive records show a trigger bit (the “Master Alarm”) as reset (“0”), as shown here (data table sorted by timestamp - see records starting at 06:32:33):
Surely this is an impossibility as the setup should only store a record when the trigger bit actually changes state?
The Transaction Group is the only thing running on the entire Ignition installation at this point. Data is coming via ethernet from a single ControlLogix PLC. The Transaction Group is running at a 1 second execution trigger, and all group items are OPC tags. There are a total of 58 boolean values being read and inserted into the table in this group.
Is there something I am missing in the configuration that could cause this? Perhaps there is a timing issue? When a trigger occurs, is the trigger bit re-read before its status is written to the data table?
Any thoughts/comments would be appreciated.