Elevator Help

Hi,

could some one help me with ladder logic diagram for a 3 level elevator, im new to PLC, i havent used it before and i just dont know how to get started with this, im currently using Zelio soft but if the ladder is in another program and its understandable i will make similar on zelio soft.

please help thanks

Welcome to the Forum, Zack !

In general, it's PLCTalk tradition to not do student homework when they simply post the question and/or an appeal to have it done for them.

You can, however, get plenty of help if you show what sort of work and effort you've put into the project so far.

So describe the sensors that you think the elevator needs to have. Floor sensors ? Door sensors ? Button sensors ?

And describe the indicators the elevator needs to have. An indicator inside the cab to indicate direction ? An indicator at the entrance door to indicate direction ? Indicators to show which floor it's on ?

And describe in English how you think the elevator needs to operate. Generating "pseudocode" that simply states the sequence of operation is a crucial first step before translating your functions into PLC memory and instructions.

Ken Roach said:

Welcome to the Forum, Zack !

In general, it's PLCTalk tradition to not do student homework when they simply post the question and/or an appeal to have it done for them.

You can, however, get plenty of help if you show what sort of work and effort you've put into the project so far.

So describe the sensors that you think the elevator needs to have. Floor sensors ? Door sensors ? Button sensors ?

And describe the indicators the elevator needs to have. An indicator inside the cab to indicate direction ? An indicator at the entrance door to indicate direction ? Indicators to show which floor it's on ?

And describe in English how you think the elevator needs to operate. Generating "pseudocode" that simply states the sequence of operation is a crucial first step before translating your functions into PLC memory and instructions.

Click to expand...

Hi Ken,

thanks for your reply, its for a project im working on but i have never used PLC before and really wanted to use PLC as my degree didnt have any papers with PLC and i really wanted to do a project which involved PLC, so i can learn something new.

i was thinking of using capacitive sensors for turning on and off the motor. i dont need a door for this. and using push button switches to select floors.

in english, i want this to work like if 1 is pressed and the lift is on level 2 it comes down to level 1, if its on level 1 and level 2 is pressed it will go up to level to but what i want it to do after the object is of the elevator it to return to level one from level 2 and 3.

I remain skeptical that this is an actual project with actual machinery, since elevators and lifts, even ones that carry only cargo, are highly inspected and regulated in most jurisdictions. Perhaps you're describing a sort of storage/retrieval or dumbwaiter lift.

Why do you think a capacitive sensor is appropriate for sensing the load ?

If there is no door, how will you "idiot-proof" the loading of the lift platform to prevent it from attempting to raise or lower with a load protruding ? Remember that the persons requesting the elevator will not be able to see its loading condition.

Unless, of course, they just look down that open elevator shaft.

Will there be request buttons on the upper floors, or only command buttons on the bottom floor ?

Do you have an appropriate lift drive or soft-start, with an appropriate backup brake ? How many inputs does it require from your controller ?

Cast yourself in the role of the "Run UP" input on the hoist drive. What events would make you run ? And what conditions would make you stop ?

And consider that the system will always need a switch to detect the arrival of the lift at each floor. Simply running the lift for a given period of time has no chance of accurately stopping the hoist at the correct position.

hello,

this im making a prototype and im starting off with a lift hoping ones i have some knowledge about programming i can build it up to something that can move up down side to side, like a platform for storage, im planning to use stepper motors. im watching videos on youtube to try get a basic program done, im planning to make something like this i will post a link below i want to learn PLC and i have seen few youtube videos so i have started a simple program on zelio soft i have the plc on hand, gonna use leds to demonstrate until program is finished and i can build a prototype like the video link.

also i want to know before i get to deep into this will i be able to do this with PLC ? or is it too hard.

what im attaching is something i want to do but i wanted to learn some basics so i can do this project.

https://www.youtube.com/watch?v=3VUMHwz89nc

motor latching set n reset

i have just done a ladder program, which turns the motor on and as soon as it gets to level 2 it turns the motor off. im gonna try doing the same for level 3. pressing a button will turn the motor on and it will turn the motor off ones the sensor has been triggered.

Zack,

Your enthusiasm for the project is admirable. Ken gave very good advice "start with pen and paper". Learning to program is as much about how you think as it is about the learning the tools. It's always exiting to play with new toys and get some instant gratification but in this instance you will need to design the software before writing it.

Things to think about:

How will I know where the elevator is?
How will I know if it is OK to move the elevator?
How will I know where to send the elevator?
How will I handle multiple requests?

Nick

Hi Nick.

Thanks for your reply and advice.

Im planning to make a elevator for my automated parking system this is like a first step approach to what i plan to do, so it will have one plank, and im planning to use barriers so if one car is on the platform the barrier will be low and the other car cannot come through until the first car is parked. so the elevator will take the car to a certain spot and ones the car has reached the platform it will come back to its original position, than the next car can park im planning to use sensors so if the car is at a certain spot no matter what button you press another car cannot go there unless the first car has been retrieved. im planning to start of using push buttons so input switches to tell the elevator where to go. since i havent done PLC before i thought it would be best to get something going up down and med level. before i can move onto the other parts. but its just hard to do as im trying to learn off youtube right now. the reason im doing this is just so i can have some experience with PLC since we never learnt it in our degree.

zacksmithnz said:

Hi Nick.

Thanks for your reply and advice.

Im planning to make a elevator for my automated parking system this is like a first step approach to what i plan to do, so it will have one plank, and im planning to use barriers so if one car is on the platform the barrier will be low and the other car cannot come through until the first car is parked. so the elevator will take the car to a certain spot and ones the car has reached the platform it will come back to its original position, than the next car can park im planning to use sensors so if the car is at a certain spot no matter what button you press another car cannot go there unless the first car has been retrieved. im planning to start of using push buttons so input switches to tell the elevator where to go. since i havent done PLC before i thought it would be best to get something going up down and med level. before i can move onto the other parts. but its just hard to do as im trying to learn off youtube right now. the reason im doing this is just so i can have some experience with PLC since we never learnt it in our degree.

Click to expand...

As above, start with pen and paper, your first task should be to draw the system as it will be configured.

Show each component that interfaces to the PLC such as switches, sensors, actuators etc. and location of them on a drawing representing the system.

You can use this as a basis for defining the sequences you require, once you have defined all the required sequences you can move onto programming the system, its easier to do it this way rather than diving into code.

alright make a state diagram with possibilities etc.
3 levels is good for practice,
so your ladder can be divided into several parts, like inputs, steps, transitions and actions.
a steppermotor is not best in a PLC as it needs to go fast.

have a look at arduino.
zelio is possible however a little small.

hi there,

i been thinking the same thing if what i want to do is possible with PLC, cause i was told today by a mate of mine to use Arduino as well, but again i have not done that either . i have made a simple up down state diagram.

tragically1969 said:

As above, start with pen and paper, your first task should be to draw the system as it will be configured.

Show each component that interfaces to the PLC such as switches, sensors, actuators etc. and location of them on a drawing representing the system.

You can use this as a basis for defining the sequences you require, once you have defined all the required sequences you can move onto programming the system, its easier to do it this way rather than diving into code.

Click to expand...

hi,

i will try to get it down on paper, but i dont understand what you mean by draw it as it will be configured i have not delt with PLC i dont know the configurations. i can get a list of components and how they will work with the system and try putting it all on paper

zacksmithnz said:

hi,

i will try to get it down on paper, but i dont understand what you mean by draw it as it will be configured i have not delt with PLC i dont know the configurations. i can get a list of components and how they will work with the system and try putting it all on paper

Click to expand...

Forget about the PLC program for now, draw the lift system, 3 floors, buttons on each, sensors on each floor, over travel sensors, label them all and identify where they will be connected to the PLC etc, then use this to identify how many operations and scenarios you have, then transpose them into the PLC language of your choice.

A PLC is more than capable of handling a system like this, as to its validity for an actual lift system n the real world i cannot comment as there will be regulations around what you can and cant do.

Arduino would be great for this, your mate is right.

But don't you already have the PLC? Interfacing sensors and motors etc. is much easier with a PLC.

I would draw a state machine (pen/paper ). Basically you will have 3 states (one for each floor). To be accurate, you will need two more states to indicate between floors 1-2 and 2-3. Assuming there can't be any overshoot.

From the states draw lines and write down the conditions and/or actions to go from one state to the other.

boneless said:

Arduino would be great for this, your mate is right.

But don't you already have the PLC? Interfacing sensors and motors etc. is much easier with a PLC.

I would draw a state machine (pen/paper ). Basically you will have 3 states (one for each floor). To be accurate, you will need two more states to indicate between floors 1-2 and 2-3. Assuming there can't be any overshoot.

From the states draw lines and write down the conditions and/or actions to go from one state to the other.

Click to expand...

Hey I haven't bought the sensors motors yet cause I was unsure if I was using stepper motors or servo, and also I just been researching type of sensors I would need I have got the programming software as off now only which I had downloaded of the Internet.

im not too familiar with arduino as well, so I have no idea how will I code, with this I had watched few YouTube videos to help me get the basics done.

I have done a simple state diagram on the operation of this.