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Ladder Diagram Example

LD Gate Example​


The LDF falling edge (one-shot) contact orientation creates an execution condition based on the ON status of the assigned BOOL data register, S, for only 1 scan.

Ladder Diagram Example​


When the falling edge (one-shot) contact, M24.5, is powered OFF, the coil, Y3.3, is deenergized.



When the falling edge (one-shot) contact, M24.5, is powered ON, the coil, Y3.3, is energized for only 1 scan.



The falling edge (one-shot) contact, M24.5, will remain OFF (unless otherwise specified) after being powered, but the coil, Y3.3, is deenergized after 1 scan.

Scan Execution Time

Since scan programs execute in less than a second, it might not appear that the coil, Y3.3, was energized.