Trafficlights PLC Alpha

[KgOlve]

Ok, so im kinda curious how i can add a .. Hmms, what's it called? .. The button pedistrians press to the cars get a red light and they can cross .. That thing ..
Yea, i wanna add that. I've tried several times, but i can't seem to get it to work properly. I can get the function, but somehow, always, it doesn't work properly. As in other lights are lit too ..

(This is made with Mitsubishi Alpha Programming, and that's needed to open the file)
Also, since i wrote the short comments in Norwegian, i'll write the simple translations
Grønn = Green
Gul = Yellow
Rød = Red
Oppe = Up (Top)
Nede = Down (Lower)

 

[RussB]

I always thought that those buttons were there just to give the pedestrians something to do while waiting, do they REALLY work?
Rumor has it that pressing this code shortens the time more:
<short> <long> <long> <short> <short> <short> <long> <long> <short>
Could you add this too?

If there is a vehicle sensor parallel with it and have your button look at the time left on the signal change timer and divide it by 2?

 

[KgOlve]

Yes, im quite sure they work.
What i was thinking of doing was that when i pressed the "pedistrianbutton", the trafficlight would still go like normal, but the next time it hit Red up - Red down, it would halt there for a longer period than it normally would, signalizing "Pedistrians: Now's your chance to cross if you don't wanna get run over"
I don't have enough exits to put in pedistrian lights, so two red lights over a longer period will have to be signal enough.
(Im not putting this out on the street xD)

And as for the "code" .. That can't be added. There is only ON and OFF here. No "On for a littlebit" or "On for a littlebit longer than a littlebit" .. There are no functions like that.
What could be done however is put in a counter which would count to a certain amount of ON-signals, and then activate some shortcut. But that would take alot of work and thinking having it do that. Because you'd also need something to clear that counter again after it's counted. Coming up with how to clear blocks is always a pain.

If there was a veichle sensor there, then the traffic light program would be turned on the head, upside down. Then Red-red would be dominant, when nothing else is on. (Meaning it's always clear for pedistrians when there are no cars there). Then the contact in the sensor which closes when it detects a car would have to work as the normal on-button starting the cycle to a green light for that car, and back to the red light.
Making it in that way would be easier then what im using in my program, namely Green up - Red down as the dominant, because than i could just cut the ON-signals to every light except the red ones, making them light up, rather than what i have to do now.

 

[leitmotif]

I think the button is commonly called a walk button.

To the question do they really work?
well a common trick in building maintenance for chronic complainers (too hot too cold) is to put a thermostat on the wall. You do not have to wire it to anything. It does nothing but it sure does seem to make some (NOT ALL) complainers happy probably because it gives them something to tinker with. Medicine calls it the placebo effect.

Maybe that is the case with the walk button - I like everyone else wonder at times. My guess is it extends the light to give pedestrian time to make it across the street.

I am not sure what you are doing but when I did a traffic light with PLC I used timers which is what they do in the real world.

Dan Bentler

 

[KgOlve]

Yea, walk button - That sounds about right ..

I know of the placebo effect, and im quite sure we install all our thermostats properly too ..

I know of a few intersections where the light will not turn red for cars unless someone presses the button, and an intersection where the light won't turn green for cars unless a sensor detects them.
So in my opinion they work ..

As for the PLC program, i did build mine with timers too. It works the way it should, lightsequencewise, i just don't remember it all, so i have to remake the whole thing, and while having it all in mind, figure out where to put what to get the walk button working.
I also do have a semi-working one with the walk button working, which is not mine. Somewhat working. It works now and then, and can only be pressed every 15 seconds or so, or it won't work ... Therefore i didn't want to be influenced badly, and didn't look at it.

Making program in Alpha is awesome, but - You have to make it all at once, otherwise you'll be puzzled beyond puzzleness next time you open it and look at it x)

 

[Oceansoul]

There is a crossing near my street and the lights are always green. Until a person wants to cross, so they press the button, then BAM the lights go instantly red. Epic bad programming there!

 

[KgOlve]

Haha. Yea, trying to avoid doing that in my program x)