Issue with leased scan class?

I am using the MicroLogix 100/1400 driver with v7.1.5 and I am seeing something strange with the scan classes. I have a scan class set up as leased mode with the slow rate at 0 and fast rate of 100ms. When I create a new tag with this scan class it shows up outlined in red and as the data is null. Even if I assign that tag to an object on a screen and launch the app the object has the overlay with the tag symbol and the wrench. If I change the scan class on the tag to one that is direct everything immediately starts working. I can then change the class back to the original leased one and it works.

Yes, it appears that there may be a few issues with leased scan classes. The “leased” state doesn’t seem to be maintained after editing the rate, and the whole mechanism that controls when they’re leased or not seems to be off. That is why you’re ending up with a situation where the scan class should be leased, but isn’t.

Fixes for these issues will be in the next dev release.

Also, I would guess that your problems in the other thread with the slow write feedback is related to this. When the leasing is out of sync with the OPC server, the server might fall back to a 1 second publish rate- which corresponds to what you were seeing. The “ant tracks” on a write go away once the write value is received as an update.