Assignment $4($SFC$)$

$-$ The mixing process has a start pushbutton that is hardwired as normally open while the stop pushbutton is hardwired as normally closed.

$-$ Once the start pushbutton is pressed, pump $1$ and pump$2$ are operated for $10$ seconds to fill the tank.

$-$ Once the filling phase is over, the mixer is turned on and runs for $60$ seconds.

$-$ After the mixing time is over, pump $3$ is started immediately and $1$ second later the drain valve is opened to drain the tank. The tank$\text{'}$s discharge time is $14$ seconds. Once the discharge phase is over, a new mixing cycle is started.

$-$ If the stop pushbutton is pressed at anytime, the filling valves are closed, the mixer is stopped, and the tank is drained. The start push button must be pressed to start the mixing cycle again.

$-$ Implement an SFC program to control the process.