You have a $3-$phase motor, M$1,$ which drives a conveyor belt. The conveyor belt is operated with switches S$1($Start$-$forward$),$ S$2($Start$-$back$)$ and S$0($Stop$).$ S$1$ and S$2$ are pressure switches with work contact $($NO$),$ S$0$ is pressure switch with rest contact $($NC$).$ All switches have automatic return. The operator must operate the switches with one push to start the conveyor belt, it should not be necessary to hold the switches in for the conveyor belt to start. In order to change direction, the operator must first press stop, it will then take $5$ seconds before it is possible to start the belt again.

a$.$

Draw the main flow diagram. Remember that the motor must have a direction of rotation reverser

b$.$

Draw control flow diagram