The latching is used where the output must be activated even after the entry ceases. A simple example of such a situation is a motor, which is started by pressing a button switch. ... The latching used to stay the motor run until the push button is pressed again.

What is latching and unlatching in PLC?

When I push the OFF button the TV turns off. I don't have to keep pushing the ON button to keep the TV on. This would be the function of a latching instruction. The latch instruction is often called a SET or OTL(output latch). The unlatch instruction is often called a RES(reset), OTU(output unlatch) or RST(reset).

What is latching circuit?

A latch is an electronic logic circuit that has two inputs and one output. One of the inputs is called the SET input; the other is called the RESET input. Latch circuits can be either active-high or active-low.