What is latching in PLC?

Latching is like a seal in contact.

Let me explain,

If you are using push button as input device means, Whenever you push it will make a contact and give output as you see in below image,

Whenever you release it, it will make disconnect the contact like below image,

But our aim is to make a contact in single push,because we cannot hold the button all over the time,for that we are using latching circuit,

For that we are using output bit to store the status,

Even though we took hands from push-button,output remains in On state,

You may ask,then how to turn OFF the lamp,

Use stop push Button,

This parallel circuit we adding under input is called latching circuit.

Hope,It will help you !

Author - Hema