Design a programmable controller program to solve the control problem for the process described in given Example and given Figure.
Example
Construct a state variable description of the process shown in Figure. The timer output (TU) is initially low when its input (TM) is low. When TM is taken high the output stays low for five minutes and then goes high. It resets to low when TM is taken low. All level sensors become true when the level is reached. The process sequence is:
1. Fill the tank to level A (LA) from valve A (VA)
2. Fill the tank to level B (LB) from valve B (VB)
3. Start the timer (TM), stir (S), and heater (H)
4. When five minutes are up take stir (S) and heater (H) off.
