I am having a strange problem where OPC tags are not being updated. I can check the “last change” property of the tag and the value will often say anywhere between 5 minutes ago to a day and a half ago. All of the tags are driven by the default scan rate, one second.
Oddly enough if I delete one of the tags in question and then recreate it it functions properly - I can watch the “last change” property change like the tick of a clock. If this were a few tags it would be no big deal, however with about 1,500 OPC tags I can’t afford the time to manually replace every one.
Solutions?
Can you call in and let us take a look at the system while it’s running?
As long as you don’t mind an international call and very slow internet.
We have had similar instances of similar symptoms, and it ended up being the deadband was keeping it from updating. In a few cases we had added scaling and didn’t change the deadband. Other instances we weren’t sure how it changed, but figured someone changed it. Not sure if this is it but it’s something quick to check/double check anyway.
Thank you for the input - I think that is probably it.
Could this problem be caused by creating an OPC tag as datatype int and then switching it later to float? This morning I’ll fix all the tags via Excel and see if the problem persists.
Update:
The problem is in fact the deadband property. However when I export the tags and modify the deadband column with Open Office, the changes don’t register. In fact, all of the deadband values are set to 1.0.
What are you trying to set the deadband to? Can you mail in your modified sqltags.csv file and I’ll see if I can replicate the problem here?
The default deadband when you export is 1.00E-004, so maybe something funny with formatting is happening.
I have sent the sqltags.cvs export file to support@inductiveautomation.com. I am trying to set the deadband to anything more accurate than 1.0. 1E-4 is a bit overkill - 1E-2 would be ideal.
OK, there’s a bug in the CSV import when dealing with scientific notation. The workaround for anybody in the meantime is to either set all the values to non-scientific notation in the CSV file (.001, etc…) or to use the Tag Search dialog to do a mass select/edit and change the deadband there.