Design of Control Circuit of an Automated Elevator Employing Mathematical Logic

Abstract

The control circuit necessary for the operation of an automatic elevator which starts and stops at specified places and at specified time is presented. At present the elevator operations are generally controlled by electromechanical relays with a large number of contacts and limit switches. Here it has been tried to dispense with relays and their contacts, limit switches etc., by the introduction of semiconductor logical and switching devices. Electronic counting technique has also been suitably used. Different logical and switching schemes to be used have been developed by writing all the logical and sequential operations in the form of constraint equations, then solving them with the help of Boolean algebra. Boolean operations are performed by different logical and switching circuits. The entire control circuit has been constructed and tested, and the results were found to be in conformity with the predicted operations. All the facilities provided in an operatorless automatic elevator are also provided by this static control circuit. It is not, however, claimed that this is the only static control circuit possible or that the circuitry used is optimum. The authors only feel that such an approach will help the elevator engineers in finding out the easiest solution to any elevator operation problem. This is surely not possible by looking at different operations as completely isolated and their circuit arrangements mutually independent.