ABB RC/A4.2 is the ABB i-bus® KNX Room Controller Basis Device for 4 modules, surface mounted. It accepts up to 4 freely assignable plug-in modules, controls their functions and communicates as one KNX bus device.

Inserted modules are detected automatically. Integrated module selection, status indication and manual controls support functional testing at the installed controller. The module functions can be tested without KNX bus voltage, but the basis unit itself requires its mains supply.

System Architecture

• Module capacity: 4 slots; compatible module types may be mixed according to the project design.
• KNX topology: The complete populated controller occupies one KNX bus-device address.
• Load distribution: single-phase mains/load supply, rated 16 A in ABB's current Room Controller planning material.
• Installation: Surface-mounted IP54 enclosure designed for decentralized room installation, including raised-floor or suspended-ceiling applications where permitted.

Compatible Plug-in Modules

• BE/M4.12.1, BE/M4.24.1 and BE/M4.230.1 — binary-input modules.
• ES/M2.230.1 and ES/M2.24.1 — electronic valve-drive switch modules.
• JA/M2.230.1 and JA/M2.24.1 — shutter actuator modules.
• SA/M2.16.1, SD/M2.6.2 and LR/M1.6.2 — switching, dimming and light-control modules.

At a Glance

Specification	Detail
Catalog description	Room Controller Basis Device, 4 Modules, SM
Order code	RC/A4.2 (2CDG110104R0011)
EAN	4016779676472
Module slots	4
Mains/load distribution	single-phase, 16 A
Supply range	85…265 V AC, 50/60 Hz (technical data)
Internal consumption	Maximum 3 W without modules
KNX	KNX TP; < 10 mA bus current
Dimensions (H × W × D)	200 × 275 × 50 mm
Net weight	0.83 kg
Protection	IP54

Planning and Safety

The Room Controller distributes mains power to inserted output modules. Installation, module insertion and wiring must be performed by a qualified electrician with all relevant supplies isolated. Use the type-specific connection diagram, installation instructions and product manual below. Select and commission the matching RC/A4.2 ETS application; plug-in modules do not have independent KNX applications.