A Controller Area Network interface module that enables serial communication between distributed elevator subsystems — car operating panel, landing call stations, drive, and controller — over a two-wire differential bus.
Full Definition
CAN bus (ISO 11898) provides reliable, noise-immune serial communication in elevator systems, replacing the multi-core travelling cables and riser cables of older parallel-wiring architectures. In a typical CAN-based elevator, the car COP, indicator displays, door controller, load-weighing device, and car call expansion modules each have a CAN node; the controller acts as the bus master. CAN operates at 125 kbit/s to 1 Mbit/s; for elevator travelling-cable installations, 125–250 kbit/s is standard to accommodate cable capacitance. CANopen (CiA 301) is the application-layer protocol most commonly used in European elevator controllers. LIN bus is used for lower-bandwidth subsystems (indicator strips, advertising displays). CAN bus wiring requires proper termination resistors (120 Ω) at both ends, correct twisted-pair cable (≥120 Ω characteristic impedance), and maximum node stub lengths of ≤0.3 m to avoid reflections. Fault diagnosis uses CAN bus analysers to view frame traffic and identify node drop-off.
