Balance control system for a movable barrier operator

A balance control system for a garage door operator, comprising:

• a motor;
• a transmission system providing connection between said motor and said door, and adapted to move the door between a closed position and an open position above the closed position;
• a counterbalance system to reduce power required of the motor to lift the door;
• an apparatus to generate first signal representing a force required to move the door from said closed position to said open position, and to generate a second signal representing a force required to move the door from the open position to the closed position;
• and
• a controller responsive to said first signal and said second signal to indicate an imbalance of said garage door when a difference between the first signal and the second signal exceeds said predetermined threshold.

A method for balance control of a garage door operator, comprising steps of:

• generating a first signal having a value proportional to an opening force used for movement of the garage door from a closed position to an open position;
• generating a second signal having a value proportional to a closing force used for movement of the garage door from said open position to said closed position;
• comparing values of said first signal and said second signal to detect a difference between said opening force and said closing force;
• and
• indicating that the door is out of balance when said difference exceeds a predetermined threshold.