Traffic Lights

matty22 · Nov 3, 2002

Can anyone tell me the PLC program for a traffic light sequence. I am doing Plcs in in a collage course and I have been set the task to find this out if anyone know it would be very helpful.

Caveman · Nov 3, 2002

ladder

light is green_____________________GO!
---| |------------------------------------------( )

light is yellow____________________go really fast
---| |------------------------------------------( )

light is red_______________________you better stop
---| |------------------------------------------( )

/ladder

Steve Bailey · Nov 3, 2002

Search the archives here. This one's been done to death.

Please post a picture of your PLC collage when you're done.

Terry Woods · Nov 3, 2002

Refer to this thread for tips...

http://www.plctalk.net/qanda/showthread.php?s=&threadid=1432

But, use this chant instead...

"BE THE COMMUTER...BE THE COMMUTER...BE THE COMMUTER..."

PS, I'd like to see your collage too!

Tom Jenkins · Nov 3, 2002

If you just want an answer, go to the appendix in the Allen Bradley Micrologix manual. If you want an education, post your attempt here and we will help find the problems. If you want a collage buy a glue gun.

porky · Nov 3, 2002

traffic lights

Try this site
http://www.geocities.com/plc_guide/

Also try Amazon.com for an English dictionary...

Good Luck Mate

jdr · Nov 4, 2002

Funny enough that this should get mentioned. I just wrote two programs for my class that are the good 'ol traffic light control jobs. One is just one-way, and the other controls an intersection. Cyclic cascading timers at its finest, my friends. I was going to post a jpg of the code and ask for tips and tricks on it, mainly going over mistakes and taking suggestions on cleaning it up. It works in simulation, but you know how that goes. At any rate, I don't have access to free image hosting, and both jpgs are too large to be attached to the post, so if anyone would be kind enough to let me know they're willing to look over it, I'd be happy to email it to whomever is interested.

Thanks,
Josh

Terry Woods · Nov 4, 2002

jdr,

Can your code handle this? Just wondering.

Yes, I'd like to see your code.

What is the file format?

PLucas · Nov 4, 2002

Deja Vu

6 or so weeks into a new college (at least I can spell collage!) term and what do we get.....

The good old traffic light question.

And of course, Terry's pictorial example of every students nightmare

My thanks to Terry for posting that picture again!

Paul

jdr · Nov 5, 2002

Terry,

I hope and pray that I never have to program something like that. Thinking about it makes me want to stop messing with controls in general...

At any rate, the programs were written in LogixPro, as I'm far too cheap to buy RSLogix just to play with at the house. Both are saved, however, as jpg images for easy viewing in a web browser, program of choice, etc... Just lemme know and I'll get them on the way.

Oh well, gotta run. My copy of "Automating with Step 7 in STL and SCL" got here this afternoon while I was at work. I'll be the envy of all my friends after reading that book.

Josh

jvdcande · Nov 5, 2002

Matty22,

a simple search for "traffic light" should have given you plenty of info. One of the results should have been http://www.plctalk.net/qanda/showthread.php?s=&threadid=258 where you find a Grafcet (or Graphcet - whichever you prefer) design for a fairly simple traffic light control. Don't panic if you don't have a 72 inch monitor, the last contribution to the thread shows the design on a more conventional format

.

Of course, this is only a design. The programming you have to do yourself. And there's plenty of info about grafcet on the internet. Just don't be lazy, get studying!

Kind regards,

Jean Pierre Vandecandelaere

Sean Caldwell · Nov 5, 2002

i think i know exactly what your doing cuz i did the exact same thing last year.

is it a push button activating the timer for the lights to change
green ligh- red man
amber - red man
green - green man and buzzer
flashing amber - flashing green man
green - red man

if so i'll try and find my code for it. its stored somewhere.

its all ladder logic you need 2 cyclic timers (1 is possible though)
couple of ton and a lot of typing up

Sean Caldwell · Nov 5, 2002

here it is actually

Sean Caldwell · Nov 5, 2002

or not.

wont let me upload the word document.

ps. it was just the flow chart and boolean

Traffic Lights

matty22

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Caveman

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Steve Bailey

Lifetime Supporting Member + Moderator

Terry Woods

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Tom Jenkins

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porky

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jdr

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Terry Woods

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PLucas

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jdr

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jvdcande

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Sean Caldwell

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Sean Caldwell

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Sean Caldwell

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