How To Choose The Correct Traffic Countdown Timer
1. Why need countdown timer
Countdown timer is used to show the amount of time left before the signal light changes, let people focus on the traffic signal, and improve the efficiency of intersection crossing traffic–the red color timer shows the time remaining before the signal light turns green, so people will have a faster response; while the green timer shows the time left before the signal light turns red, so people can decide if wait or keep crossing the road.
2. Some problems for countdown timer
Countdown timer is not a new product, but as a manufacturer, we have met many clients complaining that their timer did not work, after talking with them, we found they choose the wrong timer thus leading to the problems. Most clients just think all timers are working in the same way, so they often got problems after installation. Some frequently asked questions are:
– why timer does not display at the beginning?
– why timer does not work when pressing push button?
– why timer does not work in an adaptive control system?
– when changing signal sequence, why the timer has to take several cycles then will display?
……
3. Types of countdown timer
- From the view of the digits, countdown timer can be divided into fixed digits (include one digit, two digits, two and half digits, three digits, etc.) and non-fixed digits.
fixed digits countdown timer
Non-fixed digits traffic countdown timer
- From the view of size, it can be divided into 200mm (8inch), 300mm (12inch), 400mm (16inch), 800×600mm, 900×600mm, 1200×600mm, etc.
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- From the view of working type, it can be divided into learning type, trigger type and communication type.
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Learing type
The characteristic is the time display will start from the 3rd signal cycle–first signal cycle countdown timer will record the signal timing, second signal cycle countdown timer will check if record is correct, third signal cycle will display time if record is correct.
So this type timer can’t be used at Puffin or Pelican crossings. Besides, it can not be used for adaptive traffic control systems (meaning the time remaining is not known – the network sensors and algorithm decide). Also, it can not be used for intersections with multi-signal cycles. (time will not be displayed for two cycles of beginning when signal cycle changed)
Trigger type
This type timer no need to learn from signal cycle, it works when receiving the trigger signal from controller, so it can be used for puffin or pelican crossing and adaptive traffic control system.
Communication type
Communication type is similar with trigger type, the difference is it needs to communicate with controller by 485 terminal, so installation will be more complex, and need to know the communication protocol of controller.
4. How to choose the right type
To avoid the problem that countdown timer does not work, we need to choose the right type according to the working type: if countdown timer is just used for small intersections, and only one signal cycle, the learning type is best, because it’s easy and reliable.
If the intersection is complex, or need to work with push-button, or used for adaptive traffic system, then need to consider trigger type or communication type.
5. Wire connection
Learning type and trigger type countdown timer wire connection are the same, the communication type has an additional 485 communication cable.
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6. Some popular types in differenet countries
As a traffic light manufacturer, we have supplied many types of countdown timer for different countries, and found different countries has it’s a popular type.
- Vietnam popular types
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D200 450×500mm D300
- Myanmar popular types
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1200×600mm
- Malaysia popular types
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800×600mm
- Bangladesh popular types
D300mm