PLC Program for Parking Garage/ Door System (Studio 5000)

Question

Design a garage system to operate as follows:

1. The door is opened or closed either using a keypad or a remote key FOB.

a. Using either of these will open the door if it is closed or close it if it is already open.

b. There should be the capability of reversing the direction of the door at any time during the

opening or closing process by pressing either the keypad or the key FOB.

i. When this occurs, for example, when the garage is closing, the opening motor

should run for the same duration as the closing motor. The same is true for the

inverse.

ii. For the sake of simplicity, if the door is interrupted by another input while closing or

opening the first time, it will fully complete the reversal before the key fob or keypad can

be used again.

c. One DC motor should simulate the door opening and another should simulate it closing.

d. A light should indicate if the door is fully opened and another light if it is fully closed.

e. Two status lights should turn ON while operating and stay ON for 8 seconds after each closing

or opening of the door.

i. You may still operate the garage while this light is activated.

f. When a sensor is obstructed while the door is closing, the door should reverse and fully open.

i. A red warning light should flash for 8 seconds after this.

ii. The direction of the door cannot be toggled while the garage is opening in the warning

state and cannot be closed again while the warning light is flashing.

iii. When this occurs when the garage is closing, the opening motor should run for the

same duration as the closing motor.

2. Keep track of the number of times the door is cycled, one cycle is any command that opens the door and

any command that closes the door. (OPEN > CLOSE, CLOSE > OPEN = 1 CYCLE, NOT JUST

OPEN > CLOSE)

a. If the garage is interrupted, for example, if the garage is closing, then midway through closing, it

opens fully again, it is not counted toward a cycle.

b. After the door has been cycled two times AND the door is fully open, the system should disable.

i. An amber indicator light should turn on indicating a need for maintenance.

ii. Once the maintenance has been done, the amber light will turn off and the system can

then be used again.

3. There are three floors to the parking garage, each floor has a capacity of 5 cars.

a. Cars can only enter or leave the parking garage when it is fully open.

i. There is no restriction on how many cars can enter or leave while the door is open.

ii. Cars cannot enter or leave when the door is opening or closing.

iii. Cars cannot enter a floor if it is full.

iv. If the garage is completely full, cars cannot enter, they may only leave.

v. If the average number of cars per floor is greater than three, turn on an occupancy yellow

light.

b. Indicate a floor is full by turning on a red light, if a floor has capacity, turn on a green light

c. Use at least one array.

Answer 1

I can provide you with simplified example to get you started. For more I will need more information

PROGRAM MainProgram

VAR

DoorState: BOOL;

OpeningMotor: BOOL;

ClosingMotor: BOOL;

WarningLight: BOOL;

StatusLightsOn: BOOL;

CycleCounter: INT;

MaintenanceNeeded: BOOL;

FloorOccupancy: ARRAY[1..3] OF INT;

AverageOccupancy: INT;

METHOD OpenDoor

DoorState := True;

StatusLightsOn := True;

OpeningMotor := True;

ClosingMotor := False;

SetTimer(Timer_OpeningLight, 8000);

END_METHOD

METHOD CloseDoor

DoorState := False;

StatusLightsOn := True;

ClosingMotor := True;

OpeningMotor := False;

SetTimer(Timer_ClosingLight, 8000);

END_METHOD

METHOD ToggleDirection

IF OpeningMotor THEN

ClosingMotor := True;

SetTimer(Timer_OpeningLight, GetTimer(Timer_ClosingLight));

ELSE

OpeningMotor := True;

SetTimer(Timer_ClosingLight, GetTimer(Timer_OpeningLight));

END_IF

END_METHOD

METHOD ObstructionDetected

WarningLight := True;

ToggleDirection();

SetTimer(Timer_WarningLight, 8000);

END_METHOD

METHOD MaintenanceDone

MaintenanceNeeded := False;

AmberLight := False;

END_METHOD

METHOD CheckOccupancy

FOR i := 1 TO 3 DO

IF FloorOccupancy[i] >= 5 THEN

FloorFull[i] := True;

ELSE

FloorFull[i] := False;

END_IF

END_FOR

AverageOccupancy := (FloorOccupancy[1] + FloorOccupancy[2] + FloorOccupancy[3]) / 3;

IF AverageOccupancy > 3 THEN

OccupancyYellowLight := True;

ELSE

OccupancyYellowLight := False;

END_IF

END_METHOD

METHOD MainLogic

IF OpeningMotor = False AND ClosingMotor = False AND GetTimerDone(Timer_OpeningLight) THEN

StatusLightsOn := False;

END_IF

IF GetTimerDone(Timer_WarningLight) THEN

WarningLight := False;

END_IF

IF CycleCounter >= 2 AND DoorState = True THEN

MaintenanceNeeded := True;

AmberLight := True;

END_IF

END_METHOD

END_PROGRAM