PLC glossary
Seal-in
A way to remember a brief Start request. The pump stays commanded on until Stop or another stopping condition breaks that memory.
- Also called
- seal in, holding circuit, self-hold
- On site
- A caretaker presses Start once and the water pump keeps running after the button is released.
- Siemens
- LAD parallel holding contact or SCL logic using the previous output.
- Rockwell
- Ladder parallel holding branch or ST logic using the previous output.