Down control system
Basically in apartments, in the lifts, where the usage traffic of the elevator is low. at all landing panels there will be only one button, this is down control system.
Full control system
In high traffic usage places, shopping malls and hospitals we find two buttons on every landing with Up and Down arrows, this is full control system.
Down control system Vs Full Control system
In both these systems, cabin will stop on the floor button which ia pressed first from inside the cabin.
However when the buttons is pressed from passenger who is on a particular landing floor, lift will stop only while going in down direction in down control system, particularly to save time.
Eg. A passenger if travelling to 3rd floor from Ground floor, may have pressed 3rd floor button inside the cabin, and then lidt starts moving to 3rd floor.
Another passenger who is in 2nd floor while the lift is moving if presses the landing panel button, elevator will first go to 3rd floor and while coming down it stops at second level. Elevator logic here always works as if passengers wants to go to ground level. This avoids lift stoping everytime buttons are pressed while going up and saves little time.
In a full control system, elevator landing panels will have two buttons with Up and Down directions, passeger if wants to travel up will press Up direction button, so lift while moving up will stop and passenger who wants to travel down will press Down direction button, so lift will stop while moving down.
In a low rise building eg. G+2 because there will be three landings, even if it’s a full control system, Ground will have Up arrow and 2nd floor will have Down arrow.
In Down control system
Ground will have Up arrow and rest all the floors will have Down arrows on buttons.