The Negative Edge Trigger function block is used to trigger other logical events based on the falling transition of a logical signal. For example, you can use the Negative Edge Trigger block to trigger actions based on the shutdown of equipment.
The output of this block should not be used in a different module unless you are certain that the scan rates match and will not be changed in the future.
You can lengthen the pulse by using an Off-delay Timer function block, or you can use the pulse output to set a latch.
Application example: conveyor system
Assume a conveyor feeder gate must be closed when the conveyor shuts down, as shown in the following figure:
You configure the block to trigger an output that closes the gate when the input (conveyor motor) transitions to False (0). The following figure is the function block diagram for this example:
