MultiProtocolFrameParser.ConnectionEstablished is invoked after successfully connecting to the PMU. If it doesn’t show anything after that, it means the PMU is not sending any data. It sounds like your PMU is simply not working correctly, or maybe you are connecting to another device that isn’t a PMU.
This seems like an entirely different problem. PMU Connection Tester displays “Attempting to connect” before it establishes the connection to the PMU. If it’s stuck there, then I’d expect it should eventually time out within 30 seconds if you leave it alone.
It’s hard to pin down an exact cause, especially since you seem to be having two different problems between MultiProtocolFrameParser and PMU Connection Tester. We’d need more consistent information in order to point you in any particular direction. As for openHistorian, We don’t know anything about your setup so we can’t even begin to speculate about what data it’s receiving and from what device.