Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

23.5.1 Latches and Seal-in

 

· Latches are one function built into PLCs, but there are variations.

 

· Basically, latches allow one or more values to be frozen in time.

 

 

· This circuit is a seal-in because the output locks the inputs on. After power is removed the logic will default to off.