There are three common types of control for elevators: push-button control, collective control and destination call control.
With push-button control , only one command or call is stored at a time, with commands from the driving cabin taking precedence over calls from outside. Until the end of this journey, all further commands are blocked. This type of control is rather rare today and is only installed in smaller residential buildings or for freight elevators at the customer's request.
In the case of collective control , all commands from the driving car as well as calls from outside are stored and driven off one after the other in the current direction of travel of the elevator. The full collection control system is used especially in public buildings with elevator groups. Here, the desired direction of travel can be selected via the outer panels with two push buttons. In coordination with the stored interior commands, the next elevator stops in the desired direction of travel.
In the case of destination call control , the desired target level is already entered on the external panel. No destination can be entered in the cabin itself. This allows the journey through the elevator system to be planned precisely. This control system is particularly useful in large buildings with commercial use. Office workers can, for example, enter their destination floor by scanning an access card, and the control system names the elevator of an elevator group that goes to the desired destination. This results in an increase in the efficiency of the conveying capacity. Destination call control is particularly necessary in modern multi-car lifts, i.e. two cabins on top of each other in one shaft, in order to enable efficient operation.
Source: bauwion
