Prepare a ladder diagram for the process described in given Example and given Figure. Assume a logic off-delay 5-minute timer (i.e., goes true when enabled and stays true for 5 min). Assume a NO start push button and an NC stop push button
Example
Construct a state variable description of the process shown in given 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.
