Abstract: A discrete position encoder having a plurality of spaced apart pairs of optical sources and detectors, thereby providing a plurality of interruptible light beams, mounted on one member, cooperating with a light-occluding vane which is mounted on another member movable relative to the first member, there being at least two of the detectors which are not occluded while at least two other detectors are occluded when the two members are relatively centrally aligned with each other, the vane having a notch therein centrally disposed along the vane in the direction of relative motion, the notch being relatively adjustable in size by means of adding additional membranes, such as self-sticking plastic sheet or the like, to the vane to alter the light-occluding capacity of the notch, thereby to tailor the response of the detectors to the effective notch caused by the altering.

Abstract: An elevator employing a microprocessor-based cab controller, for controlling, among other things, the opening and closing of the elevator car door, provides a pair of dictated door velocity profile signals and selects the one having the lesser value, to dictate motor current in accordance with the selected desired door motion profile. A first one of the profiles includes acceleration up to a desired maximum velocity, and a second one of the door motion profiles consists of a deceleration profile generated as a function of the distance from the door to a desired target position. An exemplary elevator system and cab controller, along with an exemplary door control program for the cab controller, establishing an environment in which the invention may suitably be practiced, and detailed program steps for effecting the present invention in such an environment are disclosed.