Three-lift control system - has switching module for each lift, comprising free lift search circuit with direction decision switch acting on module memories

摘要

The lift control and indicator system for a large number of floors, is used to operate three lifts. The three circuits are each controlled by a module which determines which direction a call signal requires, and stores the calls in a memory system. This is carried out during the middle of travel of the next lift or in the opposite direction to the travel of the most remote lift. In the event of the signal not being answered the signal is reprocessed and allocates to the next lift. The system uses at least a minimum combination of AND and OR-gates to pass signals corresponding to test for an approaching signal, test for a receeding signal and test pulse. Each floor has its own module, these being grouped in available floor numbers. Each contains switching elements which cancel a call signal, if it has not been utilised. These modules and their groups contain chains of logic elements which enable new selection of this call signal and its allocation, when its previous cancelling has taken place.