The basic principle.
A button sends a request to the control system. A landing call may request a direction; a car button normally selects a destination. Destination-control systems collect the request differently.
The controller records the call and decides how to serve it alongside existing requests and operating conditions. A group system may assign a particular car rather than send the nearest one automatically.
A call while the doors are open.
The request can be registered while the controller completes door timing and checks. The visible acknowledgement means the request was accepted, not that movement must begin immediately.
Follow the relationship.
- RegisterReceive and acknowledge the call.
- PlanChoose the appropriate journey or allocation.
- SequenceCoordinate doors and permitted movement.
Connect it to the lift.
The controller can delay or inhibit travel when a required condition is absent. Repeated button presses do not create additional motor force or override protective conditions. Service modes can also change which calls are accepted.
A closer look
Call allocation is separate from motor control. This distinction helps explain why a scheduling delay and a movement fault need different investigation.
Check your understanding
Does a lit button guarantee that the lift is ready to move immediately?
Reveal the explanation
No. The request can be stored while other conditions or journeys are completed.