OPC servers need to be refreshed after a while

My problem is that I can’t browse for items after adding a few tags to a group without refreshing OPC servers. Here is what I do to create the problem, it works every time, and on several different PCs:

  1. Browse to a folder on the OPC server
  2. Add some items into a group from that folder
  3. Try to browse to another folder on the OPC server.

On step 3 FSQL acts like every folder is empty, and I have to refresh OPC servers, then I can browse normally until I add more items to a group. I am using RSLinx.


Yes, RSLinx does this…

This has been a known problem with RSLinx for a while, but we haven’t yet been successful in fixing it. Essentially FactorySQL puts OPC server connections into a pool, and then disconnects them if they haven’t been used for a while. In browsing, after reconnecting (after disconnecting due to the timeout), FactorySQL tries to browse from where it was at. Most servers have no problem with this, but RSLinx starts returning empty responses.

Probably the easiest/best thing we could do is make the disconnection time an option, so that you could just set it to like 30 minutes and not have to worry about it.


I see. I don’t suppose the OPC Browse Timeout setting has anything to do with it?

No, generally not, unless you’re browsing a branch with a lot of takes that might take a while to retrieve. In that case, the timeout could be interrupting it and causing the results to be empty, but I’m pretty sure you’re running into the disconnection issue.