Pleas help!

Hello all im realy in a pinch and need some help quick! I am a student and I have a project due today at 5pm in my PLC's class and I have honestly tried everything I could think of and I can not get it to function properly. first of all I am using the allan bradley logix pro 500 simulator.I completed the first part of my project which was to complete a four way stop light ladder logic using I/O simulator and tod's, but I am completely stuck on stupid for the 2nd half. I am supose to have the n/s and e/w red lights both on for a period of 2 seconds using 2 more tod or tod timers. I just cant figure this one out im stuck on stupid, and it is due today at 5pm an counts for 25% OF MY FINAL GRADE! pleas help.

lostcheif,

first off what is n/s and e/w?

secondly,
post what you have done and we will look at it and give you pointers on how to finish your work.

regards,
james

Now that you've turned off your Caps Lock key I'm more inclined to help.

If your original sequence was:
1. N/S Green, E/W Red
2. N/S Yellow, E/W Red
3. N/S Red, E/W Green
4. N/S Red, E/W Yellow
5. Back to step 1

Then add a new step 2a (N/S Red, E/W Red) and a new step 4a (N/S Red, E/W Red).

first off what is n/s and e/w?

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From many years experience with the student traffic light problem, I can answer that. It is the basice facing directions or travel directions for each set of lights, North/South and East/West. I always try to write out the full words for my light output symbols, such as "North-South Red", "North-South Green" and so on, although the LogixPro Simulator software has a very limited symbol desciption- one line of 22 characters at the "regular" font setting.

The old traffic light is a real challenge for most students because there are NO inputs to fiddle around with! As we know from many old thereads, students get intimately involved with PLC Inputs and ignore the Outputs. In this case there are only Outputs and timers, a complete student befuddlement!

For this specific exercise, called "Chapter 5: Exercise #3 - Traffic Light with Delayed Green" in the official LogixPro Student Exercises, the recommended method is to use 6 Light Outputs:
O:2/0 = EAST-WEST RED LIGHT
O:2/1 = EAST-WEST AMBER LIGHT
O:2/2 = EAST-WEST GREEN LIGHT
O:2/3 = NORTH-SOUTH RED LIGHT
O:2/4 = NORTH-SOUTH AMBER LIGHT
O:2/5 = NORTH-SOUTH GREEN LIGHT

and use 6 timers for a 28-second cycle:
T4:0 = EAST-WEST GREEN TIMER, "80"
T4:1 = EAST-WEST AMBER TIMER, "40"
T4:2 = NORTH-SOUTH DELAYED GREEN TIMER, "20"
T4:3 = NORTH-SOUTH GREEN TIMER, "80"
T4:4 = NORTH-SOUTH AMBER TIMER, "40"
T4:5 = EAST-WEST DELAYED GREEN TIMER, "20"

Later in Chapter 7, there are other more advanced methods using only 1 timer.

I cant figure out how to send my screen shot to this msg box.

im not sure what to do here,yes steve that is pretty much what I have so far im just lost on which inputs outputs or timers I should be controling with my 2 additional timers my instructor wants us to use to keep both red lights on for 2 seconds

If there are two new steps (2a and 4a), and your instructor says to use two additional timers...

I'm just lost on which inputs outputs or timers I should be controling with my 2 additional timers.

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Lostcheif,
If you set up the timers as shown in my Post #4, you only need to trigger each timer using the previous timer. The "East-West Delayed Green Timer Done" XIO is used along with a series T4:1/DN XIC, on the rung for the East-West Red Light. The "North-South Delayed Green Timer Done" XIO is used along with a XIC paralleled contact from T4:4/DN, on the rung for the North-South Red Light. The Amber and Green lights should be controlled with only TT contacts, not DN contacts.

"Delayed green" means that the next green light is delayed long enough for both red lights to be on at the same time for 2 seconds. This helps prevent cars from running the yellow lights.

You can experiment with the scan speed to see how your light system runs at different speeds. If if will run 5 minutes at 100% speed with no crashes, then you probably have a good solution.

Lancie, Steve thank you both very much I appriciate it mor than you can imagine I am a new comer to the world of plc's and I do enjoy it I guess I just have to stop over thinking an just realize what Im asking the program to do. again gentlemen thank you both very much Im sure I will be back soon nI dont have the greatest instructor he never even went over the basic do's or dont's of programming with us.

I dont have the greatest instructor

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For every student who complains about the quality of his instructor, rest assured there's an instructor complaining about the quality of his students.

I can't figure out how to send my screen shot to this msg box.

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1. Click "quick reply";
2. Click "Go Advanced";
3. Write Message;
4. Click "Attach Files";
5. Browse to your file location and select a file;
6. Click "Upload" and wait for messsage showing "Current Attachments". (Your file must be of the allowed types and sizes);
7. Close the "Attach Files" window;
8. Click "Submit Reply"

Just like a beginner, I forgot the most important step!

0. Log in to this site with your user name and password. If you are not signed in, you will not be able to post a message.
1. Click "quick reply" to reply to any previous message;
2. Click "Go Advanced";
3. Write Message (at least 2 characters long);
4. Click "Attach Files"; (Your file must be of the allowed types and sizes);
5. Browse to your computer file location and select a file;
6. Click "Upload" and wait for messsage showing "Current Attachments";
7. Close the "Attach Files" window;
8. Click "Submit Reply".

Steve Bailey said:

For every student who complains about the quality of his instructor, rest assured there's an instructor complaining about the quality of his students.

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And because there are multiple students sharing one instructor, guess who is complaining the hardest .

i suppose there is a lesson here.
your final day, final few hours and you're desperate.
You need urgent help - it is worth 25% of your mark.
Ok
You might not have known about this site - BUT
leaving things to the last minute is a big mistake!
You need to query what you are doing a lot earlier

Apart from a small nudge in the right direction, students should not be helped AT ALL !
The act of solving a problem is in itself something that has to be learned.
I am not being sadistic, just the best advice to a student is to tackle the problem by one self.
"test finishes today" "bad instructor" are not good arguments.