The pump motor control relay is controlled by the following sensors:
A: Position sensor to sense if the train car is in position. This sensor is a normally closed optical sensor.
B: Limit switch in the holding tank to sense whether there is enough fuel
to fill a tanker car. This switch is a normally open sensor.
C: Limit switch on the filler tube nozzle to sense whether the fuel level in the tanker is at the proper level (tanker is filled). This switch is a normally open sensor
CR: The pump motor control relay (CR), which functions as normally open.
An emergency stop button (neglect this is your design for simplicity).
The pump motor should turn on when the tanker is in position and there is a proper amount of fuel in the holding tank. The pump motor should turn off when the proper fuel level is reached in the tanker or the emergency stop is pushed (neglect the e-stop for this example).
1. Construct the truth table to evaluate the effect of each set of input conditions on the output (pump motor control relay).
2. Convert the truth table into a Boolean expression. Simplify the expression.
3. Draw the ladder logic rung to control the control relay for the pump motor.