A discrete event controller $($DEC$)$ controls a machine so that it starts operation when a start

pushbutton switch is pressed and there is no fault. The status of the machine and start pushbutton

switch are denoted by M and PB $1,$ respectively, and the status of the fault is denoted by F $,$ where

F$=0$ means no fault and F$=1$ means there is a fault. The controller turns off the machine when the

stop pushbutton switch is pressed or if there is a fault. The status of the stop pushbutton switch is

denoted by PB$2.$ It is assumed that a fault is detected by a sensor$.$

a$.$ Develop the software ladder logic diagram $($SLLD$).$

b$.$ Develop the PLC diagram $($define ports for inputs and ports for outputs and state variables$).$

Question $2[10]$:

To the above question, the pushbutton switch has the problem of the momentary effect. This

effect means that after the start pushbutton switch is pressed, the power will be delivered to the

machine but shortly the power will be cut off because the start pushbutton gets back to its off

status. To solve this problem, the controller needs to provide the latching function, which

suggests including a control relay $($CR$)$ in the controller. Please do the following:

a$.$ Define inputs and outputs of the controller, and state variables of the plant.

b$.$ Develop the state diagram of the controller.

c$.$ Develop the Boolean logic equation of the controller.

d$.$ Develop the software ladder logic diagram $($SLLD$)$ for the controller.

e$.$ Develop the PLC diagram of the controller.