How to generate alert messages

Hello Everyone,

I want to generate some alert like(High Temperature Alert).
But I want to generate alert only once if data is coming continuously more then threshold.
And if data is coming only one time more then threshold. in this situation I don't want to generate alert.
Please suggest me any logic or any node so i can generate alert or print any msg on debug window.

The usual way to handle this is to use a Trigger node. Use a Switch node to only pass good messages (so temperature below threshold) and feed that to a Trigger node set to send Nothing then after an appropriate delay send the alert message. Also select Extend Delay on new message. Then provided good data keeps coming in then no alert is sent, but if the data stops coming in or only high values are seen for the specified time, then the alert is sent. That is not exactly what you asked for but is often an acceptable solution, and the fact that it also triggers if the sensor fails, for example, can be a good thing.