KL2012 by Beckhoff

The KL2012 is a 24 V digital output terminal produced by Beckhoff for the KL Bus Terminal series. Within a Bus Terminal station, it acts as the interface between field wiring and the controller, allowing low-voltage actuators or indicator circuits to be driven directly from the backplane. Each channel switches its load through solid-state electronics, so no mechanical wear occurs during the rapid on-and-off sequences common in industrial automation.

The terminal is powered by a field supply of 24 V DC, which matches typical control-cabinet power rails and eliminates the need for local converters. Each channel provides a drive capability of 0.5 A per channel, supporting small pneumatic valves, relays, or signal lamps without external amplifiers. The terminal has 2 independent outputs, and their states are transferred cyclically to the PLC through a process image width of 2 output bits. This one-to-one relationship simplifies address mapping within the control program. The enclosure has an ingress protection rating of IP20, so the module must be installed inside a protected cabinet but requires no additional gasketing. The wiring uses two-wire connection technology, meaning each output uses one switched lead and a common 0 V return. A variable installation position allows the housing to be oriented horizontally or vertically to suit the cabinet layout.

The housing measures 15 × 100 × 70 mm, keeping channel density high while leaving room on the rail for additional terminals. It snaps onto a 35 mm DIN rail and connects to the adjacent Bus Coupler through an integrated side connector, so no tools are required after the rail is mounted. The terminal includes reverse-voltage protection that protects upstream supplies by blocking current if the 24 V and 0 V leads are accidentally reversed. The outputs are also short-circuit-proof. If a load draws excessive current, the affected channel shuts down electronically and resumes operation automatically after the fault is cleared.