Door operator system

Abstract

A door operator system for an upward acting sectional or one piece (California-type) garage door includes a DC variable speed motor directly connected to a drive mechanism for moving the door between open and closed positions. A motor control circuit includes circuit components for reversing the direction of rotation of the motor and for delivering a pulse width modulated voltage signal to the motor to control motor speed. A current sensor including a split core transformer and a Hall effect sensor detects motor current and provides a signal to a microcontroller for stopping the motor or stopping and reversing the motor if the motor current reaches a preset limit which is user settable by potentiometers connected to the microcontroller. Magnetic position limit switches and an obstruction detector are operably connected to the microcontroller to provide input signals indicating the state of the door and the control circuit. A motor shaft mounted encoder provides a pulse-type signal to the microcontroller to provide a speed signal and a door position signal. The microcontroller is operable to control operation of the motor to move the door toward an open position at a speed at least twice the speed of movement of the door to a closed position. The encoder and microcontroller detect maximum door travel in the door opening mode and reduce motor speed in subsequent operating cycles if the operator is connected to a one piece door.