V7.5 - Transaction Scheduling

I am attempting to setup a transaction group using the new scheduling feature.

While it seems to work properly in writing to the DB on the schedule, unfortunately, the OPC values I am collecting are never updated and show only N/A in the value column. The values sent to the database are therefore

Also, when the transaction group is initially created or changed, the group shows a ? and only changes to the green running arrow once the transaction has been run.

Am I missing something?

Are there any error messages under the ‘events’ tab in the transaction group view?

Just the standard Group State Messages, the last being ‘Group State Changed To Running’

As I mentioned, the writes to the DB are being performed, but the OPC values are listed as N/A, as if the transaction group isn’t updating the OPC values… even after it runs at the specified time.

Try making a sqltag that has the same item path as one of your group items. I’m curious if your experiencing issues with the sqlbridge module, or something in the Ignition platform.

sqltags start out marked as ‘stale’, rather than N/A. Once the group is triggered off the schedule, the sqltags are shown with values. The values were stored int he DB.

I decided to delete the group and start from scratch. This time, OPC tags worked for me.

Not sure what that was all about…

Thanks for the help…

What is your update rate on the group? And how many times did that group execute and write null values to the DB?

the update rate was whatever the default rate was. It executed ~10 times and wrote null values each time. The sqltags wrote fine and after that, I deleted the group and entered it all again using the original OPC tags, no problem since then…

Glad to hear you got it working. I will have the developers look into the issue of null values for OPC items.

FYI,

I converted 3 other transaction groups over to scheduled transactions this morning. 1 of the 3 worked with no problem. 1 threw nulls into the database as I described yesterday, the other is sitting there with a ? for the status rather than a running green arrow and will until it is triggered for the 1st time based on what I am seeing.

There is definitely something flaky going on with the scheduled transactions and OPC items on the initial setup but I can’t seem to isolate it to anything specific. Seems just hit or miss…

Having these groups sitting with an unknown status after setting them up or making a change to them, before they trigger is rather misleading.

Can you attach an export of your project and tags so we can take a look?

I can…
SF_Batch_Data_Collection_2012-06-21_1228.proj (583 KB)

Now that I have your project open, of those 3 groups you mentioned, which one had no problem, which one wrote nulls, and which one sat there with a ? status?

Hi,

First off, the “unknown status” situation is a known issue. The group only sets its state when it executes, so it will sit like that until the first exec. We’ll try to get this fixed for 7.5.1.

Now, as for the null… since you say that they don’t update in the UI either, I suspect something is going on with the subscription. The opc subscription is a bit tricky with scheduling, because if you don’t have a range in your schedule, the rate box isn’t editable. In this case, the group is supposed to manually read- although now that I take another look, this appears to not quite be true right now.

At any rate, try this:

  1. Go to Status>OPC Connections in the gateway. Do you see the items that aren’t working displayed anywhere in the subscriptions list? What rate are they listed at?
  2. Try overriding the OPC subscription rate on the Options tab.
  3. Optionally, instead of #2, try setting the OPC Data Mode to “Read” on the option tab.

By doing 2 or 3, the group should get values. The first exec or two might have nulls, as it sometimes takes time for values to come in, but then they should arrive.

Let me know how it goes,

I should have defined that one for you…

Formulation Totals - no problem
Soap Finishing Majors Totals - nulls
Soap Finishing Minors Totals - unknown Status

[quote=“Colby.Clegg”]Hi,

First off, the “unknown status” situation is a known issue. The group only sets its state when it executes, so it will sit like that until the first exec. We’ll try to get this fixed for 7.5.1.

Now, as for the null… since you say that they don’t update in the UI either, I suspect something is going on with the subscription. The opc subscription is a bit tricky with scheduling, because if you don’t have a range in your schedule, the rate box isn’t editable. In this case, the group is supposed to manually read- although now that I take another look, this appears to not quite be true right now.
…[/quote]

I can deal with an unknown status… thanks for letting me know…

FYI,

What I was doing before is an always run expression item looking for the time to trigger in a Historical Group. This always worked fine.

To use the built in scheduling, I made a standard group and copied the tags from the historical group into it and set the scheduled times. These tags, which were properly displaying values in the historical group, are what gave me the problems in the standard group with scheduling turned on…

I tried reproducing the issue regarding copying tags from a historical group to a (scheduled) standard group, but it worked fine. It appears that the solutions Colby mentioned about OPC subscription rate and setting the OPC data mode may be the way to go.