PLC glossary
Latch
A remembered ON value that stays on after the original request ends. Another instruction must deliberately turn it off.
- Also called
- latched command
- On site
- A high-level alarm stays displayed until the water falls and the operator resets it.
- Siemens
- S/R coils or explicit SCL assignments can store and clear a BOOL.
- Rockwell
- OTL/OTU instructions or explicit ST assignments can store and clear a BOOL.