Edge Modes

There are three distinct modes for a trigger - it can be called on the rising edge, the falling edge or both edges.

In this case 'edge' means when the trigger condition (for example, that the temperature is higher than 70 degrees) changes.

A rising edge is a movement from a low value (False/0) to a true value (True/1).

A falling edge is a movement from a high value (True/1) to a false value (False/0).

If responding to both edges, the function will be called both when the value changes, regardless of direction.

Note that you can check the Condition property of the trigger to check if the condition that caused the function to be called was True or False.