two-storey lift problem

[natur3_07]

Hi to all,
I¡¦m a student who's given a lift project to do and I need help.
This project is concerned with a simple goods lift operating between two floors in a manufacturing plant. The lift is powered by a motor and can be called to or dispatched from any floor using the pushbuttons located on each floor. There are also status lights on each floor to indicate where the lift is parked.



Specifications:
- There is a call button on each floor
- A status indicator lights up if the lift is in that floor
- Inside the lift there are open and close buttons for the lift door to open and close and select the respective floors
- There are LEDs to indicate direction of movement(UP or DOWN)
- the lift user has to select the respective floor by pressing the appropriate button in the lift and the UP and DOWN contactor must be activated accordingly.
- If the lift is already in the same floor where the call button is pressed, the lift door will have to open for 10 secs then close. If the lift door has to be opened for a longer time the person has to HOLD the button manually.
- If the lift is I another floor the lift will move UP or DOWN based on the current floor. 5 secs is taken to move from one floor to another. After the lift reaches the floor from where it is called, the lift door will open for 10 secs and close.
- Once the lift is in motion, it cannot change direction till it finishes the current task and will go back to serve where the button is pressed earlier after the current task is completed.
The PLC specified is NAIS PLC FP0-14RS, which comes with 8 input ports(X0-X7) AND 6 outputs(Y0-Y5). Whereby X6 and X7 are pushbuttons.

Can anyone tell whether I have started right by putting:

Inputs:
Outside lift:
X6-UP push button(LEVEL 1)
X7-DOWN push button(LEVEL2)

Inside lift:
X1-OPEN button
X2-CLOSE button
X3-LEVEL 1 button
X4-LEVEL 2 button

Outputs:
Y1- Indictor light 1
Y2- Indictor light 2
Y3-Door open/close
Y4-LEDs up
Y5-LEDs down And also please tell me how many relays should I be having and should they consist of. Please do tell me where can I find sample ladder diagrams similar to this question to this project too.. Help will be greatly appreciated..

 

[STL???]

Hi,
How do you know when the Elevator is in position at the desired floor?

How do you know whether your Doors are Open + Closed?

Just 2 things i quickly see, that need to be thought about.

If you search the Forum threads or Downloads section you will find example elevator programs, But more likely in Allen Bradley Code, Its still Ladder after all!!

Good luck

 

[bernie_carlton]

What output actually causes the lift to go up/down?

 

[rsdoran]

Inputs:
Outside lift:
X6-UP push button(LEVEL 1)
X7-DOWN push button(LEVEL2)

Inside lift:
X1-OPEN button
X2-CLOSE button
X3-LEVEL 1 button
X4-LEVEL 2 button

Outputs:
Y1- Indictor light 1
Y2- Indictor light 2
Y3-Door open/close
Y4-LEDs up
Y5-LEDs down

Be aware that this is a student exercise and not a real elevator, you basically do not have enough I/O for a real one.

Technically you could use just one input for Call Elevator, the action would depend on what floor it is on.

I would not worry about getting too fancy but if you can add sensors to show what floor it is on that would help. If you have to do it as assigned then forget it.

On the outputs I would use one for door open and one for close, you will need to time the door open part.

The up motor/LED and down motor/LED can use the same output so do not worry about that part.

 

[Lancie1]

In addition to your Inputs and Outputs, I would add the following internal relays. If you want to design it so that it can be expanded to more than 2 floors, consider using relays to call these subroutines:

RELAYS for Subroutine calls:
DO NEXT MOVE OR WAIT
CLOSE DOOR & GO
CAR IS MOVING
STOP & OPEN DOOR

RELAYS for internal decisions:
GOING UP
GOING DOWN
CAR REQUEST-1ST FLOOR
CAR REQUEST-2ND FLOOR
FLOOR REQUEST-1ST FLOOR
FLOOR REQUEST-2ND FLOOR
OPEN DOOR
CLOSE DOOR

Additional Output needed to respond to Emergency Stop condition and to apply brake when stopping:
STOP CAR