Platform gate door device

A platform gate door device comprising:

• a platform gate door installed on a platform at a position where passengers get on and off a vehicle;
• a door control device for opening and closing the platform gate door;
• at least three photoelectric obstacle detectors disposed between the platform gate door and the vehicle for detecting a presence of an obstacle, wherein each obstacle detector has a light emitter and a light receiver disposed on either side of an opening of the platform gate door;
• a switching means for activating one of the at least three obstacle detectors;
• and
• an obstacle detector failure determination unit configured to operate in such a manner That when the obstacle detection process for determining failure is started, at first, the obstacle detection process is performed using the two obstacle detectors, next, the obstacle detection process is performed using the further obstacle detector, and if the detection results from the at least three obstacle detectors are all the same, it is determined that the at least three obstacle detectors are normal, and if the detection results vary, then the majority results is determined, and the obstacle detectors outputting the majority results are determined to be normal, while the obstacle detector outputting the minority result is determined to be at fault.