plz help me out ,,,,to implement this logic.

respected sir,i want ur help,,
i got 4 floor model of an elevator,,,with 4 cabinet-call push buttons on each floor,,the problem i m facing is,,,i can't make ladder(program),,,to give priority,,i.e. for example suppose the cabinet
is at 3rd floor an is now called from ground floor,,
when it is travelling towards ground floor it is again called by 3rd floor first and then 2nd floor,,,,,,
so the sequence occur like this---cabinet goes to ground floor it
stays there for 10 sec,,,,then it should move up to 3rd floor ,,,,,
stops there for 10 sec,,,,,and finally comes to 2nd floor and stops..

please help me by sending your ladder diagram which take all this conditions in mind b'coz i m just bugged off thinking about this ,
plzzz
send as soon as possible

You probably won't get a ladder diagram here but think about this. On floors other than the bottom and top there are typically two buttons, an 'up' and a 'down' button. Think about how these differ in their affect on the action of the elevator, especially considering the elevator's current direction of movement and current position.

Well, there are several way to do this.
One very common way to solve this is to
use FIFO stack:

Every time button is pressed, you put the
value associated with thelevel in your queue
and increment pointer. Every time level
is served, remove it from queue and process
next one until all are done.

For more help on your homework you should provide
additional information such as PLC type,
software version you use, I/O assignment etc.

Of course you should provide some sample code
as well. Just so we know that you are trying
to work on it yourself instead of waiting for
finished code.


panic mode

thank u panic and bernei..........

i m working with messung plc XMP820 mini plc,,,software i m using is doxmini.....basically has ladder programming....
i m totalling agreed with your thought of using FIFO,,but how??
b'coz FIFO function block in my plc has only one I/P,,,,and there are
4 push buttons to call,,,,by the way i must tell u that the model i m wotking with is fixed and can't be modified,,,,i mean in case by adding some more inputs if u suggest is impossible.....
so how to use FIFO???????

re: elevator

Ohhhh....Deja Vu, either that or I need better medication.

Most of the regulars here discourage giving completed homework to students on this forum - no matter how many time you ask. You don't learn anything and so it wastes our time and yours.

Post your first attempt at the program here, and you will get help.

Tom Jenkins said:

Most of the regulars here discourage giving completed homework to students on this forum - no matter how many time you ask.

Click to expand...

Or how many punctuation marks you put in your post....

xmp820 plc

Dear Swapnil,

I need ur help. I am using xmp820 plc in my factory, I have the software doxmini. I now require the circuit diagram of serial converter to communicate between a PC and PLC using this software. Will u help me?

Thanking You.

Regards,

M. Muthukumar.

Blind leading the blind....

logicmuthu,

Getting back to your first question, did I understand that correctly that your using 4 buttons (one for each floor) on each landing?

You should only have two buttons at each floor UP and DOWN.

On the other hand the Car Operating Panel (COP) will have buttons for all floors.

FIFO is not effecient in an elevator application. The calls should be taken in order of direction preference only. For example if the elevator is going in the up direction you should stop only at the floors that you have calls for in that direction. Lets say the elevator is on the 1st floor and you have a down call at the 2nd floor, and a car call at the 3nd floor. The elevator will bypass the 2nd floor down call and stop at the 3rd floor, then on the way down stop and pick up the 2nd floor down call.

Your direction preference will be set by two seperate rungs that will filter the calls by the position of the elevator. We commonly refer to these two rugs as "call above" and "call below".

"call above" and "call below" will interlock so that the elevator will set a direction preference and only pick up and drop off passengers traveling in the current direction preference. Once the elevator has answered the top call or reached the top landing, then it will reverse and pick up all the down calls.

If you have more than one elevator in a group then this starts to get a bit more complicated, and you will need to have logic along the same lines but decide which elevator will pick up the up and down hall calls on the fly.

Good luck with your project.

Mike.

What we have here is ........

What we have here is failure, to communicate! Sounds like a line from a famous movie! Where is ELEVMIKE when you need an elevator expert? He likes this kind of thread!
Wow, while I was typing this post, ELEVMIKE to the rescue, saints preserve us! Go get em Mike!

elevmike said:

logicmuthu,

Click to expand...

Sorry Mike, it was Swapnil who posted the original question.

elevmike said:

did I understand that correctly that your using 4 buttons (one for each floor) on each landing?

You should only have two buttons at each floor UP and DOWN.

On the other hand the Car Operating Panel (COP) will have buttons for all floors.

Click to expand...

You can assume that the person who set this homework question is NOT an expert in lifts (elevators to my American collegues).

Originally posted by Jay Anthony

Blind leading the blind....

Click to expand...

I can't argue with that!

Paul

You should only have two buttons at each floor UP and DOWN

Click to expand...

Actually the Fomula for the number of Buttons is...
B=N+(N-2)+N
Where N= Number of Floors
B= Number of Buttons

You need 10 Inputs for your lift.
6 For the Floors, and 4 Inside the Cab.
Then again there is still
Open Door
Close Door
Alarm
So maybe that's 7 Inside the Cab, 13 Total.
At least I think????

Good luck.

Jay Anthony said:

Blind leading the blind....

Click to expand...

No doubt!

Based on the home country he's indicated, this guy might be on the other end of the phone the next time you call tech support.