I'd like to check my intuition about a heartbeat tag I'm using to monitor an OPC DA interface. I'm seeing a strange behavior where sometimes the heartbeat seems to pause for a second before continuing to periodically increment. An example is shown in the image below:
Looking through PI Square and the documentation for the OPC DA and the UniInt interfaces, I can see that the heartbeat would be interrupted if the interface shuts off. But I'm trying to figure out the possible reasons for a heartbeat pausing like this? I also have PI Performance Monitor tags on the interface machine and it never seems to be using more than about 20% of its RAM or CPU, so the interface machine itself doesn't seem to be overloaded. In a case like this, I'm suspecting loading of the OPC server is likely the culprit. (There are an awful lot of polling tags.) Does that sound reasonable or is there something else I should be considering here?