Strange problem with Transaction Group

I’ve been trying to figure out this problem for sometime now, without any luck!

Let me try to explain:
I’m using SQL Server Express(2014) as my database.

I have several Transaction Groups that record Tag Data into a database table. I have some on Timers and some on Schedules.

They all do as expected EXCEPT for (1) group, this group is set to record every 30 minutes.

But here’s what happens: Every few days it records a NULL value instead of the actual tag data for 1 row, them everything is good again for a few days and it will happen again.

My server is on a UPS so I don’t think it’s a power problem and all of the other groups work as they should.(Ignition and SQL Server on same computer)

Does anyone have any Ideas that I might start to look at?


Some thoughts:

  • If I recall, you’re on v7.9.x, is that still right?
  • Are you also recording the quality of the tag?
  • Is there anything in the status window of the group?
  • Are you using an Ignition tag reference or an OPC tag created within the group?
  • Is there anything in the gateway log concerning the connection to the PLC?

Yes, I’m still on 7.9.10.

I don’t record the quality of the tag. These are MQTT tags which are updated every 3 minutes from the MQTT publisher.

The status window of the group shows “Green Arrow” (I can’t find what that means)

These are MQTT Tags that are updated every 3 minutes from 7 different MQTT publishers and it effects the whole row (which is equal to 4 tags from each publisher)

Where is the log file I need to be looking at?

Meaning the status pane at the bottom if there’s any events listed in the group or in the diagnostic log at the gateway’s web page.

OK, Thanks. No events in the status pane, but I will have to get back to office to check Gateway Logs.

Will keep you updated.

1 Like

So I’m not sure if this is the same issue, but we see something similar with some of our groups. What we are seeing as that the triggered expression tag get executed but it seems that the SQL write happens before the expression has written to it’s final destination tag so we end up seeing NULL in the table even though the tag shows the correct value - albeit a second or so later.