Patent ID: 7358480

Claim:
An operator to move an access barrier comprising: a motor drive; a counterbalance system selectively engageable with said motor drive, said counterbalance system adapted to move the access barrier between limit positions when engaged by said motor drive or when moved manually; an encoder wheel associated with one of said motor drive and said counterbalance system, said encoder wheel rotating whenever the access barrier is moved; a counting encoder associated with said encoder wheel and generating a count signal when said encoder wheel is rotated; a controller which receives said count signal and which maintains a primary count and a secondary count to determine a position of the access barrier regardless of whether the access barrier is moved by said motor drive or manually; and a profile table maintained by said controller which correlates operational parameters with barrier position, wherein said controller compares data stored in said profile table with actual data generated by said counting encoder to determine which of said primary count and said secondary count to use in determining the position of the access barrier.