Traffic Light With Walk Buttons

[hoodedrat]

Ok guys, I wrote a traffic light program, I do not have RS Logix at home so I cannot post the code, however it uses a sequencer with 2 counters, 1 counter controls the yellow lights for ns/ew and the other counter controls the red and green light, my problem is that I need to have a walk button put into it... I havent any clue where to even start, all this input has to do is add 10 seconds to the red light of the direction that the person is walking in, however the red and green are on the same counter... and even if they werent how would i make the button at 10 seconds to the counter and then when the 10 seconds is up make the counter go back to normal. Well I dont know what I can do... anybody got some help they can offer please?

 

[Steve Bailey]

If you can't figure out a clean way to add new features to your existing design, maybe it's time to reconsider the design. You may be looking for a way to electrify a candle when you really ought to be developing a light bulb.

Sometimes, the motto "If it aint broke, break it" is more appropriate than "If it aint broke, don't fix it.".

 

[elevmike]

I think you want to use the crosswalk button to LD - OUT a value in the counter accumulator, that would in effect reset the timer and jump the counter to a different position, thus starting the cycle for the green light at thte cross walk. With out being able to see the code it's diffucut to tell you exactly what you need to do.

When your at school, do a screen print and save it to a floppy, bring it home and post it here.

good luck..

 

[Bitmore]

Great Ideas going already!
I would suggest adding a timer bit in the step logic. It should disable the "next" step until the timer is done counting. You could use the same logic but add the timer NOT done bit into the step enable rung logic. For a walk indicator, anytime the pedestrian signal is active AND the step counter/timer is on, turn on an output to light the "WALK" sign, when the timer times out the "WALK" light goes off and the next step is activated. If nobody pushes the walk button the timer is NOT reset and already done!
I am certain there would be as many ideas to follow as there are stars, and we have allot of "stars" here.
Just a....
bitmore

 

[dpatto01]

rs logix 500

I have a copy also. whats wrong with posting the files I do all the time. I know u cant ditribute illegal copys of rs logix 500

 

[mordred]

If the counters are controlling the SQO instructions this probably means that the time on/off on the red light and the green light are the same lengths. You would probably find it easier if you replace the counters and SQO statements with straight timers. Without seeing the code this is only a guess though. For the SQO instruction if you right click on the instruction you should get display special to see what outputs are being set at what points in the program. Also traffic lights are one of the more frequently asked questions here. There is a good chance that the answers to your questions have already been posted. Do a search

 

[panic mode]

walk button...? those teachers are getting real good...

 

[harryting]

Extra Points: IR Green Light trigger for emergency vehicles.


-back to OP, do you HAVE to use a sequencer?

 

[Rod]

I would give an 'A' ONLY if the student had the inneciative to add the pedestrian walk/halt flashers along with the emergengy vehicle green light pass.

Of course, the way I grade, I'd be lucky to get a 'C' - then again 18 years in the business and never had someone sue me.

You want a traffic light challange?! Use MApquest to zoom on 7th St.@University here in my home town of Fort Worth Texas. Now THAT is PLC thesis material!

Rod (The CNC dude)

 

[bernie_carlton]

Now, some of our lights change their timing depending on the level of traffic in the turn lanes as seen by cameras (not the 'issue a ticket if going throug red light' type). Maybe include that. Also some go to flashing red in the less used direction and flashing yellow in the other starting at about 2:00 AM and ending at 5:00 AM, though this changes depending on daylight savings time. How about putting that into a question? (Of course then, there's always the zebras)

 

[CT782]

Opticon is the control method they use here for Emergency vehicles. Fire trucks, etc... have a strobe on top that flashes a unique pattern. Reciever at the light senses it and switches. Not sure if Opticon is a brand name or just nickname. Interesting concept though.