Consider a process that consists of a liquid chemical tank with two level indicators, a heater inlet and outlet pumps, and two valves. Assume that we want to perform the following sequence of operations:

(a) Start the sequence by pressing button S.

(b) Fill the tank with liquid by opening valve V1 and turning on pump P1 until the upper level L1 is reached.

(c) Heat the liquid until the temperature is greater than TH. The heating can start as soon as the liquid is above level L0.

(d) Empty the liquid by opening the valve V2 and turning on pump P2 until the lower level L0 is reached.

(e) Close the valves and go to step (a) and wait for a new sequence 16 start. Thaw an information flow diagram, sequence function chart, and ladder logic diagram.