摘要 |
The invention relates to a monitoring system for monitoring a door (10) of a lift installation, said door being either a shaft door, which closes the entrance to the lift shaft, or a cabin door of a lift cabin. The shaft or cabin door comprises sensor elements (12, 14) for monitoring the state of said door, i.e. its position. An evaluation system (20), which is connected to the sensor element (12, 14), evaluates the signals that are provided by the sensor elements (12, 14). The evaluation system (20) evaluates the signals of the sensor elements (12, 14) in short time intervals, in order to record the state of the monitored shaft or cabin door and temporal changes in the signal characteristics of the signals of the sensor elements (12, 14). |