An elevator control mode that registers both up and down hall calls and serves them in the current direction of travel, stopping only for calls in the car's direction before reversing to collect opposing calls.
Full Definition
Selective collective control (SCC) is the dominant single-car control logic for modern passenger elevators. It operates on directional segregation: (1) Up-collective phase — while ascending, the car stops at every floor with a registered up hall call or car call; down calls on passed floors are queued but not served until the car reverses; (2) Reversal — when the highest registered call is reached, the car reverses direction; (3) Down-collective phase — while descending, the car stops at every floor with a registered down hall call or car call; up calls above are queued. This minimises unnecessary reversals compared to earlier single-automatic operation, reduces average waiting time, and improves energy efficiency. In residential and medium-traffic commercial buildings, SCC on a single car provides effective service. Modern SCC controllers use microprocessor-based logic with energy-saving features: automatic standby floor parking (typically at the main landing), lighting shutdown, and drive sleep mode at low traffic periods. SCC requires separate up and down call buttons at each landing, distinguishing it from simpler full-collective or single-automatic systems.
