Pause and resume a sequence

Hi, I am doing a mini project which requires me to pause(freeze) a sequence using stop button and pressing start button will resume the sequence.

My question is how to acheive above condition using the ladder diagram?

Chew mj said:

Hi, I am doing a mini project which requires me to pause(freeze) a sequence using stop button and pressing start button will resume the sequence.

My question is how to acheive above condition using the ladder diagram?

Click to expand...

Implement a state machine in ladder. Use the state of a start/stop to switch from one step to the next.

Let us assume you know how to program a state machine.

Now you have two options for stoping and starting:
1. Pausing the sequence simply stops it transitioning to the next state.
2. Pausing enters a new state, where you program what needs to happen when paused, for example stopping movement, leaving a pneumatic cylinder on, turning a cylinder off, whatever. You have to program the transitions into and out of the Pause states. Sometimes easier to have one pause state per normal state. Sometimes easier to have one single pause state and just store the previous state.