Start-stop-seal Ladder Diagram

For PLC systems without latch and unlatch instructions, a circuit is needed that will allow a process to start, continue to run after a start button is released, and stop under control of another button.

A circuit that implements this functionality is commonly referred to as a start-stop-seal circuit.

A feedback path (i.e. a contact) that references the output is normally used to seal around the start contact

Start-stop-seal Ladder Logic

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