I am working on a large system and I noticed some OPC tags freezing. The tags in question are integers that do not change a lot, I am using them to inform summary of status and mode of operation, like:
Normal mode = 0
Locked out = 1
Maintenance mode = 3
So, it is not exactly a tag that changes that much.
We already tried multiple troubleshooting procedures here, the observed behaviour when the tags freezes are:
a. The tag keeps its quality as “Good” and the time stamp from the last change that was captured by the system.
b. Using the OPC quick client we see the variable with the right value.
c. If I change anything in the tag, or even copy and paste it, it starts to respond and works well for a few days.
OPC quick client