Traffic Lights Again

D.DUCK · Jun 4, 2002

PLEASE ANSER THIS QUESTION........HOW DO YOU PRODUCE A FUNCTIONAL LADDER LOGIC PROGRAME WHICH WILL PRODUCE THE REQUIRED MODE OF OPERATION FOR A TRAFFIC LIGHT SYSTEM.....MANY THANKS TO ANY ONE WHO ANSERS WITH OUT MOANING.......

Allen Nelson · Jun 4, 2002

Tom Jenkins said:
I have several ideas.

First, do a search on this site. Traffic light problems abound, as they appear to be the most common application for PLCs, far exceeding slicing pickles, for example.

Second, you need to make a list of all of the inputs and outputs for the system - that is, a detailed list of everything that the PLC is turning on (outputs like Green North, Amber South, etc.) and signals it is receiving (penguin at south east crosswalk, for example.)

Then, you need to go to your text, and find out what makes a timer time, and an output turn on, and a contact close.

Then you need to write a detailed description of each step in the cycle.

Then you need to read the tutorial on this site.

Then you need to replace each event in your description with the corresponding ladder logic command (on = contact closed, for example).

This was the first reply to the first of three traffic light requests. Perhaps you can be the first, IN THE HISTORY OF PLCs.NET!!! to follow these instructions. Someone says something like this at every student post. Students are the ones who moan, not us.

93lt1 · Jun 4, 2002

Goody said:
I hear M Mouse is an expert at such things, maybe he can help

hehe

babybylar · Jun 4, 2002

i divided my lights up into four counters;
red yellow yellow green
counter1 *
counter2 *
counter3 *
counter4 *

babybylar · Jun 4, 2002

I dont know why my graph didnt post
I took counter 1 to control the green light on road "A" and red on road "B".
I took counter 2 to control the vice-versa of counter 1
then I took counter 3$4 to control the yellow while leaving
the red light on the opposite street still on; til yellow goes out

Eric Nelson · Jun 4, 2002

babybylar said:
I dont know why my graph didnt post

If you are including an attachment, make sure that after you've selected the file you click "Submit Reply" and not "Preview Reply"... Previewing will clear the "Attach File" location, and you'll have to re-specify the attachment...

jvdcande · Jun 5, 2002

Try to make a Grafcet or something on which you could easly reason. I included one I use to teach my students to THINK! Once you have reasoned it out, then - AND ONLY THEN - start to build your program.

Scooter · Jun 5, 2002

I wish I had a 72 inch monitor to see that.

Eric Nelson · Jun 5, 2002

Scooter said:
I wish I had a 72 inch monitor to see that

Good one Scooter! I'm guessing their motto is...

"BELGIUM... We're a Small Country, but we have BIG Monitors!"....

-Eric

Rick Densing · Jun 5, 2002

It looks fine on my 64

jvdcande · Jun 6, 2002

Sorry Scooter and Eric, but her in Belgium we also don't have 72 inch monitors. I guess it was the combination of a shortage of time and that **** Murphy's law. I hope this is somewhat better, I seem to be unable to preview a reply with the attached file, I only get a look at the reply without the image.

rodney1972 · Apr 18, 2005

ladder logic

hello all i am doing a final project for school can anyone give me some tips on getting the ladder logic for street lights. i would greatly appricate it.

davidg68124 · Apr 18, 2005

Rodney, Did you even read the PREVIOUS POSTS?!!?David

Steve Bailey · Apr 18, 2005

So this guy walks up to a cop in Manhattan. The guy asks the cop "How do you get to Carnegie Hall"? For the cop's answer, scroll down.

Practice!

The same advice applies to ladder logic for the traffic light.

Rod · Apr 18, 2005

Scooter,

You don't have a rear projection screen system?

Traffic Lights Again

D.DUCK

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Allen Nelson

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93lt1

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babybylar

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babybylar

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Eric Nelson

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jvdcande

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Scooter

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Eric Nelson

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Rick Densing

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jvdcande

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rodney1972

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davidg68124

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Steve Bailey

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Rod

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