SENSING THE POSITION OF A DOOR

摘要

A sensor assembly for a door operator having a motor (501), a drive train, and a controller (130). The sensor assembly comprises ah input shaft (226) connectable to the drive train to be rotated therewith as the door is opened and closed even when the drive train is released from the motor. A magnet (215) is coupled to rotate with the input shaft (226) and its orientation is determined by a fixed sensor (218) to accurately sense the position of the door. The magnet (215) has less than 360 degree relative rotation over the full range travel of the door. Thus, when the drive train is disconnected by a manually operable clutch, the magnet (215) rotates with the door movement so that when the drive is reconnected, the controller (130) will be able to immediately determine the absolute position of the door.