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common failures of traffic signal controller and appropriate solution

     With more than eight years profound accumulated industry experience in led traffic signal ,BBM will offer our customers a summary of the issues they may encounter during use and also the corresponding resolution. The summary can be helpful in forming an accurate judgment the first time when the led traffic signal fails to work ,and help to take immediate remedial measures to avoid disturbing the traffic order.

  1.If the traffic signal controller doesn’t work and without current, the fuse may blew out. Remove the protective tube and replace it.


  2.led traffic signal light bulbs group occasionally blink and the time of flashing is less than 0.5 seconds In this case the drive board may loosen and it should be plugged in tightly .


  3.led traffic signal light bulbs keep a flash of yellow light, not artificially set.

  1)Green Conflict may exists in phase setting. Or a certain phase do not contain any led traffic signal light bulbs group and a new phase scheme is needed.

  2)Red lights of led traffic signal light bulbs group in a phase may be all damaged. You’d better check the working conditions of each light in the led traffic signal light bulbs group.


  4. Traffic signal controller works well with the indicator light displaying properly ,but led traffic signal light bulbs fail to illuminate.

  Failure causes may be that protective tube on the output plate of traffic signal controller is damaged.if not,check the circuit of led traffic signal light bulbs to confirm if they are short-circuited or earthed.

  5. Command center cannot communicate with traffic signal controller at the intersection.

  Take a laptop computer to the intersection and connect it with communication interface to ensure the natural communication between computer and traffic signal controller.

  1)If the communication is correct, there maybe an fault with communication lines or communication device.

  2)If cannot communicate, there may be some failures in RS232 interface chip of communication board and you’d better change it.


  6.Traffic signal controller works well with the indicator light displaying properly ,while there are led traffic signal light bulbs group keep on being lit up.


  Firstly, observe the brightness of the led traffic signal light bulbs. If the led traffic signal light bulbs is in low level lighting compared to the normal and led traffic signal light bulbs adopts the approach of capacitor step-down, the solution is to putting 5W47K resistors in parallel between drive line and common line.


  If the led traffic signal light bulbs appear to be the same brightness as usual,possibly because SCR drive breaks down and you need change it.