The rise of the elevator as a fundamental implement for multi-storey urban buildings in western society has caused lift companies to find themselves faced with a number of frequently asked questions from customers less versed on the subject.
One such question has to do with what options are available in terms of call logic and control systems. These types of systems tend to be divided into two categories, and the specifications of each of them are detailed in the lines below.
Automatic Push-Button Control Systems
Automatic push-button control systems, or APBs, are the simplest type of control system, and tend to be present mostly in older lifts.
APB systems operate on a call-by-call basis. What this means is that, unlike more modern systems, they do not ‘remember’ or store calls; therefore, any button presses made while the elevator is completing a trip will not be remembered, and the lift will only react to the next call made after it stops moving. This slow, cumbersome process is part of the reason why this type of system fell out of favour with lift companies, and was largely replaced by the type listed below.
Collective Control Systems
Collective control systems are the standard type of logic system chosen by lift companies when installing brand new lifts. The main advantage of these systems as opposed to APBs is that they are able to store calls, and can therefore operate faster and more efficiently across trips.
Collective control systems tend to fit into one of three types: down collective, where the lift will ignore all calls whilst moving up and answer them in order on the way down; up collective, which works in the exact reverse order; and fully collective, which involve an ‘up’ and ‘down’ button on each floor and are able to answer calls in sequence regardless of travel direction.
As noted above, most lift companies will opt for this latter type if given the choice; however, it is always useful to know what other options are available!