COURSE:
SUBJECT:
Lecturer:
Mechanical Engineering
Automation and Control Systems - AMEM 326
Dr. Sotiris Omirou
Car Park - PLC Ladder Logic Diagram
The figure below shows the layout of a simple car park. It has an entry barrier and an exit barrier.
The car park itself has six spaces and a series of displays to indicate whether it is full, has spaces
or is empty.
Ladder code needs to be written that will allow cars into the car park when it is empty or has spaces
and to exit the car park through the correct barrier. Ladder code must also be written to control the
display lights in the centre of the screen.
Develop a PLC ladder logic diagram which will incorporate the following sequence of operations:
1.
If a car is at the entry barrier and the car park is not full, latch open the entry gate.
2.
While the entry gate is open, run a timer.
3.
When the gate is open, increment the car count.
4.
When the timer is done, close the entry gate.
5.
When a car is at the exit barrier, latch open the exit gate.
6.
While the exit gate is open, run a timer.
7.
When the exit gate is open, decrement the car count.
8.
When the timer is done, close the gate.
9.
When the counter is at maximum, light Full.
10. Set the lit state of Spaces to the opposite of Full.