Car parking system is one of the examples in PLC program using RSLOGIX 500.
Car Parking System
There are two garages for parking four wheelers in the building. Each garage occupies maximum of 5 cars at a time. Each time cars enters PLC automatically counts it to a total sum of cars found in the garage.
If Limit exceeds, garage filled lamp should turn ON and directs other drivers to Gate 2 garage parking.
If Limit exceeds in both Gate 1 & 2, parking closed signal will turn on that a garage is full and notifying other drivers not to enter because there is no space available.
List of Inputs and Outputs
PLC Car Parking System
PLC Car Parking Logic Description
Latching rung to operate the system through Master Start and Stop PB.
Gate 1 entry to allow vehicles to enter using entry sensor.
RUNG0002 & RUNG 0003
To count the number of cars(maximum 5 cars in each garage) entry using counter, If limit exceeds, Garage Gate 1 filled lamp will turn ON.
RUNG 0004 & RUNG 0005
When exit sensor turns ON, Exit gate should on to make a count using counters.
Rung 0006, 0007, 0008, 0009, 0010
When Garage 1 is completely filled; Gate 2 garage follows the same procedure as above mentioned logic.
- Up counters are used to accumulate car entry, Down counters are used to reduce one in the accumulator valve.
- One shot is used to give single pulse to counter.
The above explained Car Parking process is for example only. It may vary from real time. We can use this example program to understand the working of Counters and interlocking concept function in AB PLC.