SignalTraffic Forums

by **RunsWithCrouse-Hinds** on Mon Nov 03, 2008 11:00 pm

I've been fiddling with the programming on my Econolite ASC-8000, and I set up some coordination patterns for different times of day (not so much to coordinate but just to adjust the timing at different times of day). I am having the hardest time though trying to figure out what exactly splits do. I have obviously entered some split values which are relatively random, but I still don't really know what is going on.

Here's an example. One of my cycles is 200 sec. long. In it, I have, say, in order from phase 1 to phase 8:
40%, 30%, 0%, 20%, 30%, 40%, 0%, 30%. Phase 3 and 7 are 0 because I have them set to be omitted from all sequences right now anyway.

Additionally, I have specified that phase 2 and 6 are to be the coordinated phases in this pattern. Phase 2 has a minimum green time of 30 sec, and I think phase 6 has 20 or something like that.

So, given that information, what effect does the split percentage for a given phase have on its timing? Also, what do the split values for the non-coordinated phases do? What I observe is that the coordinated phases get to be like 90 seconds longer than usual, while all other phases time normally (minimum green times only). I don't understand why the split percentages don't apply to all phases.

Can someone dig me out here?

Thanks,
Dan

by **SignalLab** on Tue Nov 04, 2008 9:58 am

Dan,
Sounds like you need the Econolite Help Desk :lol:

(not me ) but I do know a little about coord timing...at least that is what they pay me for! :lol:

Couple of things right off the bat. Your controller is seeking to get in a pattern, but it is not (at least from your example) in a pattern. That is why you are getting green times that don't sink with your %ages.

Rules for SPLITS: You are dealing with a dual ring controller where phases 1-4 (ring 1)must equal 100%, and phases 5-8 (ring 2)must equal 100%. Change your split percentages to be the same in both rings (1-30%, 2-40%, 3-0%, 4-30%, 5-30%, 6-40%, 7-0%, 8-30%.).
Now that will fix your ring balance, "but wait I want more time on split 1 than on 2". That is fine also know that the sum %ages of phases 1 and 2 must equal the sum of the split %ages for 5 and 6. This way when the light will leave the coord phase of 2 and 6 at the same point in time. You will need to make sure that splits 3+4 and 7+8 or in you case 4 and 8 add up to be the same %ages.
For example you could do:
1-30%, 2-45%, 3-0%, 4-25%, 5-20%, 6-55%, 7-0%, 8-25%. Or any combination thereof as long as you adhere to the above.
I would also lower your min times on all phases where your min times DONT exceed your split time. that will also knock you out or prevent you from going into coord!
Try this out and we will get thru this? I assume you are doing this by hand...If I lived closer we could oad it up via laptop and you'd have it...but this is a good way to lean
Good luck and let me know!
Dee

by **RunsWithCrouse-Hinds** on Tue Nov 04, 2008 10:31 pm

OK, here are my revised splits. Splits are in percentages. Also note that I set cycle 1 to have phase 1 as a lagging phase.

Cycle 1 (200 sec.), Split 1:
PHASES: 1 2 3 4 5 6 7 8
25 45 0 30 17 53 0 30

Cycle 1, Split 2:
PHASES: 1 2 3 4 5 6 7 8
33 33 0 34 33 33 0 34

Cycle 1, Split 3:
PHASES: 1 2 3 4 5 6 7 8
30 40 0 30 30 40 0 30

Cycle 2 (150 sec.), Split 1:
PHASES: 1 2 3 4 5 6 7 8
33 33 0 34 46 20 0 34

Cycle 3 (100 sec.), Split 1:
PHASES: 1 2 3 4 5 6 7 8
30 30 0 40 30 30 0 40

Should this be working? I can't really tell so far, but it doesn't seem too much different from before. If I recall, when I was running (I think) Cycle 3 split 1, phase 2 and 6 were still held for like 60% of a cycle or maybe more. Also, I noticed that the cycle percentage never really starts at any particular point, it's always random. I would think that it would start at the beginning of one of the coordinated phases, which are 2 and 6. Usually what happens instead is it CROSSES 0 while holding phase 2 and 6.

Thanks for helping me out! I should probably actually talk to you more, as I'm interested in going into transportation engineering, and I'd like to learn more about the work.

-Dan

by **SignalLab** on Tue Nov 04, 2008 10:44 pm

Dan
check your min green times and wind all of them down to say
Ph1=5 sec
Ph 2=12 sec
Ph 4= 8 sec
Ph5=5 sec
Ph 6=12 sec
Ph 8= 8 sec
If you want to run the full split time, max recall that phase.
Also if there are any...check your ped times 5 sec walk 15 sec ped clearance and zero out you density times.
Make sure your time clock is set.
Your cycle timer should be consistent and should cross-if the offset is referenced to the BEGINING Of Green- zero at the begining of the coord greens 2 and 6.
Also give the controller as many as 4-5 cycles to simmer down and make its adjustments to your setting after you have initially fired it up.
I don't see anything wrong with your split %ages.
Let me know how this goes
Dee

by **RunsWithCrouse-Hinds** on Tue Nov 04, 2008 10:55 pm

Thanks, I'll try that. If I were to max recall, say, phase 2, 6, 4, and 8, should I adjust the max time to some value that would suit the percent splits? Even better, is there maybe some document I could read that would educate me on this subject? I did download and print all 300 something pages of the Traffic Signal Timing Manual, but I have yet to read it.

-Dan

by **SignalLab** on Wed Nov 05, 2008 7:54 am

Dan
regarding max recall....you can go ahead and max recall all of your phases.
regarding the max times....there is a setting in the controller under the coord settings where you can essentially override the max numbers called "MAX INHIBIT". Make sure that is turned on...in some controllers it is default which is why I failed to mention it. :thumbsup:

The Traffic Signal Timing Manual will help you in developing some actual timings but not necessarily implementing them into your controller. You need an Econolite ASC manual for that. I will look around and see if we still have any....make take a few days but I will run you a copy if we have one or an original if we have more than one...We used to have these on the street but with the advent of 170s (in Ga) and then 2070s our were shelved. :this:

Dee

by **RunsWithCrouse-Hinds** on Wed Nov 05, 2008 8:02 am

Thanks, I will look for something along the lines of max inhibit.

I do already have the manual, actually. I ordered it from OMJC signal. I just don't know much about the reasoning behind split timing.

-Dan

by **RunsWithCrouse-Hinds** on Wed Nov 05, 2008 8:36 pm

I enabled max recall on all phases and found the inhibit max under the Coordination options menu, and voila, it coordinates! Thanks!

Here's another question (I'm full of them). Suppose I didn't use the inhibit max for some reason, but I still wanted coordination. First of all, why would I want this? Second of all, how would I achieve this? Would I have to do calculations so that I had max values and/or min green values that were "just right" for the split? I did notice that this controller actually has two available max extension categories, called MAX1 and MAX2. In the coordination options menu, you can opt to use MAX2 for coordinated functions.

-Dan

by **SignalLab** on Wed Nov 05, 2008 10:11 pm

"Here's another question (I'm full of them). Suppose I didn't use the inhibit max for some reason, but I still wanted coordination. First of all, why would I want this?"
Inhibit max tells the controller to use the split %age and not the max (1 or 2) time. Here is the only reason(that I have used) I would utilize Max 1 or 2 instead of inhibit max-if I had a really long walk plus ped clearance time. Say you have a wide road that occasionally gets a a ped call. You will have to use a big A.. split to cover your walk plus ped clear plus yellow plus red to keep from dropping coord every time a ped is actuated. Lets also say you don't want to give up all that time to that split every cycle for every random arriving vehicle. So you set your controller to Max 1 or 2 and set your max time for LESS than your split time. Your light will only extend the green to satisfy the max time IF no ped has been actuated. If the ped is actuated the true split is run and you remain in coord.
If you run free late at night and you want to keep the green time for a particular approach lower (and not cover the ped time) then select max 2 to run with your coord plan.
have fun
Dee

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