While commissioning GST beam detector, all the lights (red,yellow,green) are flashing in sequence. Can anyone tell me what is the reason. How can i rectify this?

1.detector failed to adjust automatically

2.cannot enter normal monitoring.

Rectify the steps.

      Remove the detector’s top cover, and power up the detector withVDC.

      And check the green light flashing or illuminate continuously.

 If green light continuously illuminate ,the detector is strong.