Question

A baking oven conveyor system (to bring raw dough through an oven to bake bread) needs the ladder logic to be built for proper function.

Here is the sequence of events:

a. A Conveyor Motor relay output will start (and will be latched/set on) when a normally open pushbutton (Start Conveyor) or a normally open sensor (Package Sensor) energizes. A normally closed E-Stop (Emergency Stop) push button that is not energized is in series with the aforementioned circuit components.

b. A normally open internal relay called Conveyor Motor will energize a heater coil relay output

c. The Package Sensor (normally open) and an internal relay (normally open) called Heater Coil Relay output will energize an indicator lamp called ‘Baking Started’

d. On the rear end of the oven, a proximity sensor will sense when the bread dough is coming out of the oven on the conveyor. This normally open proximity sensor (Finish Bread) will unlatch the Conveyor Motor relay output. (Hint: Each letter step above represents one rung of logic)

Question 1: Please put together the ladder logic necessary for the proper operation of this oven. Please put the correct labels on each PLC symbol that is used. (11 pts) Question 2: Only for the first rung of logic used for the program above, please generate a truth table with the 3 input variables and 1 output variable (4 pts)

Answer 1

Question 1: Please put together the ladder logic necessary for the proper operation of this oven. Please put the correct labels on each PLC symbol that is used.