Logic in lifts

Abstract

The purpose of this work was to build a sequential logic circuit for a lift controller, and to examine whether digital transistor logic could be used effectively to build the required logic system, The control sequence of a lift system starts when a floor call is registered or when the ‘carcall' push button is pressed within the car, The logic control equipment then determines what command is going to be given to the lift motor field regulator, The command is based on calls already registered and in general the call selector obeys fixed rules of logic, The lift car moves up and down the shaft answering calls according to the pulses received from the controller, Starting should be jerk free, and the lift should then travel between floors as fast as possible but consistent with passenger comfort. At the approach to the floor at which a call is registered a ‘correct zone’ signal starts a controlled deceleration of the car, which brings it to the required level, and the lift steps, The doors then open, and after a short delay the doors should automatically close again, The lift will then proceed to answer the next call.[...]