Option for no DB connection and/or no table name

There are times when I’d like to use FactorySQL to monitor a tag or tags in a PLC and then take an action when certain criteria are met. I’m not going from OPC to DB or DB to OPC. Couldn’t there be an option for “No DB connection”?

I’m monitoring the set points on a process machine. If any one of the set points changes, a SQL query action item writes a 1 to a field in a table. In this situation I do need the DB connection, but there’s no need for a table name on the Action tab because the table is in the SQL query in the action item. In fact, someone here told me to use “unused” as the table name when answering a question about this about a month ago. Doesn’t it seem a little strange that you’d have to type in “unused”? Why not just have a check box for “No table”?

Just yesterday I set up a group to monitor the length of a string tag. I had an action item set to clear the string if the length of the string equaled 14. In this case the database connection didn’t matter because the group was actually going from OPC to OPC. And again, the table name wasn’t used. This is just the latest example of doing this, even though I ended up re-doing this in the PLC ladder code today. The feature would still be nice.

We’ve been toying with the idea of OPC->OPC groups. Consider the feature requested.

There's nothing magical about the word "unused". It just means the group will try to use a table called "unused". I think what that poster was suggesting was to just have all groups with this situation point to a single meaningless "dummy" table.

Anyhow, in general, absolutely. There should be group types that just let you execute expressions and write to opc without any database reference at all. This will definitely work its way into the next major version, though the time frame is a tad foggy right now.


I know it's not magical :slight_smile: I understand what the poster meant and what its purpose is.

I'm glad you've already thought about this and you're planning on putting it in the next major revision.