# Do the skills of traffic signal repair apply to industrial controls?



## wildleg (Apr 12, 2009)

yes .


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## frenchelectrican (Mar 15, 2007)

Yes indeed iit simuair so.. It will be eaiser when you get in the  industrrail side...


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## chicken steve (Mar 22, 2011)

In my humble experience, there's nothing quite like being the center of attention up in a bucket fixin' lights ,with everyone yellin' '*TURN IT GREEN*'

:no::no:
~CS~


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## JRaef (Mar 23, 2009)

I have a friend in that business, we compare notes about our workday sometimes. He thinks what I do is way more complicated, yet I have no clue as to how a traffic controller works (never seen one on the inside). He jokes that 90% of what he does is "righty tighty, lefty loosey" because most of the time he is just replacing lamps. And now that they are going LED, he's doing that even less. But his description of the controllers sounds a lot like a PLC to me.


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## joebanana (Dec 21, 2010)

"Power distribution"? Not even. PLC maybe, can't hurt.


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## micromind (Aug 11, 2007)

Having done quite a bit of both, yes, they are somewhat similar.

Traffic signal work would be what I consider the very easiest of control work. Compared to a good part of my industrial control work, hooking up a signal is a lot like hooking up switches and outlets. 

Basically, a signal has 2 parts; detection and lights. 

The detection is usually either loops embedded in the road or cameras. Both go to a simple terminal board, but you need to hook the correct phases (traffic lanes) up to the correct terminals. This includes the pedestrian pushbuttons. 

The lights land on another terminal board, usually at the bottom of the cabinet. It's pretty easy to get the correct phases to the correct terminals. 

As an employee of a contractor, I never deal with the controllers or the conflict monitors. When I'm done with the cabinet, it's in flashing red. The city installs the controller and conflict monitor and does the programming, testing, etc. 

Traffic control work is basically digital inputs and digital outputs. Industrial controls often have these plus analog in/out, various temperature detection, pulse detection and so on. 

Interesting note; just about every traffic signal has more than a few code violations, the most obvious are;

1) #14 on a 40, 50 or 60 amp single pole breaker. Short circuit protection is provided by blowing up load switches (basically electronic relays). 

2) Very few poles are grounded. 

3) Often #16 is used from the bottom of the pole to the signal head (120AC).


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## theForce (Mar 21, 2013)

thanks micromind. i am so surprised that the big bad traffic signal certifications I have to get are really just as basic as a theater light & sound application--just something basic, compared to the control system at an automotive factory. One guy mentioned those signal controls come no where near the contols of a power system--now I know why. Say, that's why they made us write traffic light programs for the PLCs used in trade school.


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## emtnut (Mar 1, 2015)

Chances are if your working for a contractor on traffic lights, you'll be just pulling 27conductor cable ... standing poles and installing and/or changing lights.
If you do get IMSA certified, there are not many municipalities that will let you near the controller unit.
The controller unit is similar to a PLC, but it's hardware is specifically designed around the conflict monitor. Any u/g conductors short out will cause the lights to go in flash. As will any 'miss programming'.
u/g loops are the preferred inputs, but many areas are using video detection along with laser vehicle counters. These are all on a RS485 BUS connected to the controller.
There are 2 standards.. Nema 170 controllers, and CalTrans.
If you become certified with either controllers, you have job security nation wide.. US and Canada ... except California, where you need CalTrans cert.
It can be good experience, and if you get good at it... traffic jobs pay HUGE!


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## splatz (May 23, 2015)

What does it look like inside the controls housing, is it similar to industrial controls? Slotted duct, terminal blocks, rows of relays, labelling, bundling, etc.?


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## theForce (Mar 21, 2013)

emtnut; Just so you know I'm interested in your post, I located info on the specifications. The US Government provides a detailed overview in the article "Traffic Signal Controllers and APS Technologies". Econlite publishes this document "NEMA TS2 Fully-Actuated Advanced Traffic Controller". The TS1 is from the 1970s and the TS2 the late 1990s. The newer standard is the 2070. Nice to know there is a way to get certified in a specification. That would be essential to repairs to the software and hardware of the signal controller and conflict resolving sub-system. However, I wonder if the IMSA cetified technician can look over the signal controller program to identify malfunctions. If the rules are not to let an IMSA guy touch the controller; is'nt that like not letting the motors and controls (electrical/electronics) tech. touch a PLC? This person can not look through ladder logic when necessary--to home in on a malfunction? Is it that unusual to use the ladder logic program to locate a fault in a long list of inputs/outputs?


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## emtnut (Mar 1, 2015)

Bigger municipalities have their own staff. The engineer who does the timing, and a technician installs the timer unit and tests it. If they don't have the field crews, they farm that part out. MTO in Ontario does it that way.

Around here IMSA certification is required, but it wasn't that long ago that it was a tech that was company trained. The Signals crew weren't electricians either, and as Micromind said, the code violations were wild :blink:

ESA is starting to crack down on them a bit, and the service feed needs to be installed by an electrician. If you work on the service feed, or power feed be careful... Most of the older installs have parallel grounds 

Smaller municipalities farm the whole thing out to an Engineering company. The field staff all require IMSA cert.

The controller is not ladder logic, it is proprietary software that does the proper phasing, coordination, timing plans, and communication.
But any electrician or tech can wire up the 120V inputs and outputs to the terminal blocks on the controller.


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## Ninjazx916r (Apr 1, 2011)

It's just inputs & outputs. Inputs as a call/demand from a vehicle or a pedestrian. output as in red, amber or green lights.


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## micromind (Aug 11, 2007)

Ninjazx916r said:


> It's just inputs & outputs. Inputs as a call/demand from a vehicle or a pedestrian. output as in red, amber or green lights.


Yeah, I forgot.....another code violation is that a lot of older signals around here use red for the red lights, yellow for the yellow lights and green for the green lights. 

These days, it's brown for the green lights.


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## theForce (Mar 21, 2013)

a substantial savings $$


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## ce2two (Oct 4, 2008)

The easiest part of signals is the hardware,206 p.s,204 is the flashers,50 amp one pole bkr.,430 relays ,iso relay,logic relay,170 or 2070 controller,conflict monitor ,diode board ,police panel,input and out put files for loops.The software you cannot buy ,they teach it at caltrans, it takes two weeks, when you get out of class you are still scratching your head, you need hands on or you will never understand it , been there done that.To work for caltrans you do not need to be state certified .Caltrans is always looking for electricians ,good signal patrolmen are hard to find or even train.The 2070 is user friendly,the 170 lol.


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## ce2two (Oct 4, 2008)

micromind said:


> Yeah, I forgot.....another code violation is that a lot of older signals around here use red for the red lights, yellow for the yellow lights and green for the green lights.
> 
> These days, it's brown for the green lights.


You mean brown wire is the green light .You are correct:thumbsup:


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## ce2two (Oct 4, 2008)

micromind said:


> Having done quite a bit of both, yes, they are somewhat similar.
> 
> Traffic signal work would be what I consider the very easiest of control work. Compared to a good part of my industrial control work, hooking up a signal is a lot like hooking up switches and outlets.
> 
> ...


When the signal goes from hardware flash to normal operation the fazes that go green are always 2 and 6 these are the main line fazes .


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## micromind (Aug 11, 2007)

ce2two said:


> When the signal goes from hardware flash to normal operation the fazes that go green are always 2 and 6 these are the main line fazes .


It's different here, 2 and 6 are always north and south, 4 and 8 are east and west. 

When the signal is in flash, the controller continues to run as normal and the pilot lines on the load switches are lit as they would be if the signal was in normal operation, but the signal lites are all flashing red.

When it's taken out of flash, whatever phases are green on the load switches will be green at the signal lites. If you need certain phases to be green when it's switched to normal, wait for those to appear on the load switches then hit the 'stop time' switch. The controller will stay the way it is until the 'stop time' switch is placed back to normal. 

Provided of course, that the conflict monitor doesn't send it back to flash again......lol.

Interesting how different areas use different schemes.


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## emtnut (Mar 1, 2015)

ce2two said:


> When the signal goes from hardware flash to normal operation the fazes that go green are always 2 and 6 these are the main line fazes .





micromind said:


> It's different here, 2 and 6 are always north and south, 4 and 8 are east and west.
> 
> When the signal is in flash, the controller continues to run as normal and the pilot lines on the load switches are lit as they would be if the signal was in normal operation, but the signal lites are all flashing red.
> 
> ...


Around here, the timer keeps timing as well, but when it comes out of flash, it goes amber on side street (4 and 8)... helps alert traffic that the lights are out of flash.


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## glen1971 (Oct 10, 2012)

In my neck of the woods, specializing in traffic light controls would make for some pretty skinny days, or a lot of travelling.. We've got one in town and a total of 3 in less than an hour drive in any direction from town... lol...


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## emtnut (Mar 1, 2015)

glen1971 said:


> In my neck of the woods, specializing in traffic light controls would make for some pretty skinny days, or a lot of travelling.. We've got one in town and a total of 3 in less than an hour drive in any direction from town... lol...


My town is soooo small .... "How small is it ?"

It's soooo small, we dont even have a flashing beacon :lol: :laughing:


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## Ninjazx916r (Apr 1, 2011)

It all depends on the person programming the controller. It can also be programmed in the software flash to however they want the intersection to start. When you take it out of software flash, it will go whatever it is programmed. Some places starts with amber on side streets, some go on solid red for 5 seconds on all four direction, some just serves the turn lane green. It's up to the programer programing it.


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## oliquir (Jan 13, 2011)

In my little city i do the traffic light controls (maybe 15 units total!) , they are just basic plc with one for controlling lights and another for monitoring. They had specific traffic light controller before but they were too complicated to modify cycles. And now since they all have led lights they are all fused under 5A so we don't really car anymore about wire gage.


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## Ninjazx916r (Apr 1, 2011)

I dont know if i consider this 100% plc. I see it more like hvac devices. PLC logic stuff has more play. These devices in the signals are similar to hvac units. Mostly plug and play. PLC on the other hand, i think can do a lot more.


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## ce2two (Oct 4, 2008)

Ninjazx916r said:


> It all depends on the person programming the controller. It can also be programmed in the software flash to however they want the intersection to start. When you take it out of software flash, it will go whatever it is programmed. Some places starts with amber on side streets, some go on solid red for 5 seconds on all four direction, some just serves the turn lane green. It's up to the programer programing it.


Only a traffic engineer decides what the signal does or does not do..


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## ce2two (Oct 4, 2008)

Traffic signals go on flash because of a low volt DC power supply problem below 18 on a 24 vdc p.s,also wires grounded in conduits,open noodles,bad load switchs ,bad 170 or 2070 controllers,bad eproms,conflict monitor problems,primary and secondary greens on same phase are out or burn out.Conflict monitor does not monitor the yellows or the reds only the greens.The number one thing people forget about checking when troubleshooting a signal is the police panel.:laughing:


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## Ninjazx916r (Apr 1, 2011)

Should send this thread to w.e.c.a. Lots of good info here fir signal class lol


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