"Simple" 3 Floor Elevator "Relay" Diagram

NT01221

Joined Oct 10, 2012
5
I am looking to build a 3 floor working model elevator using relays and limit switches. Not worried about doors opening and closing or variable speed, just a simple 3 floor up/down operation. A 2 floor diagram is quite easy, however adding a 3rd floor makes it that much more challenging using relays. Does anyone have a simple relay diagram they could share? I'd like to have an "up" call button on the 1st floor, an "up" and "down" call button on the 2nd floor, and a "down" call button on the 3rd floor. There would be an external panel of three buttons to represent the panel inside the elevator car for floors 1, 2 & 3. Put your thinking caps on, and please.... keep it simple!!

MrCarlos

Joined Jan 2, 2010
400
Hello NT01221

You can start by analyzing the circuit in the attached image.
then:
Could change the switches shown in the image attached by magnetic sensors that activate the relays.

After:
Increase call buttons on the other floors

I hope this information will help you make your project

regards

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NT01221

Joined Oct 10, 2012
5
Thanks for your reply. I was hoping to get an actual relay diagram if someone could help me with that?

Joined Apr 30, 2011
1,581
This seems like a PLC programming assignment for school.

NT01221

Joined Oct 10, 2012
5
A good friend has an Autistic child who is fascinated with elevators. I wanted to build a working model for him, however I never worked with PLCs, so I wanted to keep with the technology I know. Would love a relay diagram if someone could help!

JDT

Joined Feb 12, 2009
657
Not simple - but interesting! I'm sure it can be done with relays - they must have done it that way back in the day. You will need latching relays to be able to "remember" things. Complicated! Get it wrong, you will have to re-wire.

I would start this project by first: Consider what input and output devices you need. Example: at each floor you need a position switch to tell that the lift is there. A call button at each floor. An acknowledgement light at each floor to signal that the lift is coming. Motor forward (going up). Motor reverse (going down). I make that 6 inputs, 5 outputs. Might be more!

Then the important bit. Draw a "state diagram". Each state is a box. Each state has a fixed output condition which is shown inside the box.

How many states? 3 for the lift stationary at each floor. Probably another 6 for the lift travelling between floors - up and down. Draw arrows showing how the system moves between states. Note that, unlike the lift, the "states" move instantly.

Work out which inputs have to switch to cause the state to change to the next state. Mark these on the arrows. For example, when the lift is stationary at the middle floor (at-2 state), it could either go up (going-up-to-3 state) or go down (going-down-to-1 state). What inputs have to change for this to happen? Not all inputs have to be acted on in every state. Example: if it's at floor 1 then the call button at that floor has no effect.

Once you have got this right - and it might take some time! Then you can plan your control system. This is called a "systematic" method. I would draw your diagram on the computer in Visio or LibreOffice Draw so that you can change things until it's right.

The beauty of a PLC over relays is that these states can be created in a "state machine" (Google that!). Directly simulating your diagram. Could also be done with CMOS logic or a micro-controller.

Last edited:

williamj

Joined Sep 3, 2009
180
NTO1221,

Search this site for elevator and/or dumb waiter, there are several here already made out.

williamj

NT01221

Joined Oct 10, 2012
5
Well I guess by adding that third floor, things get complicated very quickly! I think I may go with just 2 floors and add a few extras like opening and closing doors, lights and a bell maybe. I never worked with a PLC before, but it sure sounds like the way to go. Looks like there are allot of used PLCs on EBay at great prices. Can anyone recommend a good type for me to look for as something to play around with? Maybe an Allen Bradley SLC100 or an Omron Sysmac Mini? Keep in mind, I need something simple to program. I assume you use some kind of ladder diagram software on a PCM and then load it into the PLC???

JDT

Joined Feb 12, 2009
657
Yes, plenty of PLCs on Ebay. The problem is programming. Make sure you can get the programming software before you buy. Some PLC not only need expensive software but also need a programming device or dongle to connect the PC to the PLC.

Some more enlightened PLC manufacturers give away their programming software free, only charging for the actual PLC device (Omron and Matsushita - if I remember correctly).

Another way to do this is to use a PC as your control system. using Serial to I/O or USB to I/O modules. This is known as a "soft PLC".

Have a look at: http://www.audon.co.uk/cubloc_cpu/cb220.html

NT01221

Joined Oct 10, 2012
5
Thanks again! I had a look at the Cubloc and have one ordered along with the training board so I can play around with it!

gerty

Joined Aug 30, 2007
1,305
Here's one we bought for school, you can choose how many inputs and outputs you'll need.
You can download the software for free, write your program, try it on the free simulator, then buy the apprpriate Super Relay.
http://www.classicautomation.com/micro-PLC.aspx

Saqib Mughal

Joined Nov 17, 2015
1
Please I need 3 floor elevator relay circuit diagram.simple and clear please send me at yahoo id s_saqi72@yahoo.com