HOW IT WORKS - Lift prioritisation

In the vertical transportation industry, lifts need to prioritise the order in which they visit floors in order to keep people waiting the least amount of time. The Otis Autotronic elevator was the first lift to consider traffic patterns and peak times, bypassing floors when fully loaded. First installed in the Atlantic Refining building in Dallas, Texas in 1950, these relay-controlled elevator systems remained the main way of prioritising floors for the next 30 years.

In the 1980s, microprocessors took over and are now used to control every aspect of the lift operation. As well as the passenger interaction, a series of sensors, controllers, sequences of operation and real-time calculations – or algorithms – balance the passenger demand and car availability. These sensors provide data on car positions (if there is more than one lift in the building), car moving direction, loads, door status, hall calls, car calls, pending up hall and down hall calls, number of runs per car and alarms.

From that data, a management system consisting of a workstation and the manufacturer’s software can then create metrics for a group or particular car such as total number of door openings, number of runs per car or call, and up and down hall calls. For buildings with multiple lifts, prioritisation programs will assign passengers going to the same destination the same lift. And some programs will even group floors to assigned lifts to create a faster, better-organised service.