ABB RM/S2.1 is the ABB i-bus® KNX Room Master, Premium, MDRC. It controls apartment areas with a bathroom, typically in hotels and small apartments, through 18 inputs, 13 outputs, one shutter output, three fan outputs and two pairs of electronic outputs for valve drives.

Preconfigured Premium model with the broadest RM/S I/O set, including a shutter channel plus fan and valve-drive functions. ABB specifies a VD3-or-higher device file.

Integrated Room Functions

• Inputs: 18 binary inputs.
• Outputs: 13 switching outputs, 1 shutter output, 3 fan outputs and 2 × 2 electronic valve-drive outputs (21 outputs total).
• Local operation: Supported.
• KNX integration: The Room Master is a complete KNX TP DIN-rail device, not a plug-in module for the RC/A Room Controller.

Model Selection

Room Master variants have materially different input/output layouts and application concepts. Select the exact RM/S2.1 type for the required room functions; terminals, channel counts and application parameters must not be inferred from another RM/S model.

At a Glance

Specification	Detail
Catalog description	Room Master, Premium, MDRC
Order code	RM/S2.1 (2CDG110095R0011)
EAN	4016779665674
Inputs	18 binary inputs
Outputs	13 switching outputs, 1 shutter output, 3 fan outputs and 2 × 2 electronic valve-drive outputs (21 outputs total)
Maximum switching current	20 A
Output voltage	230 V AC
Power loss	8.15 W
Dimensions (H × W × D)	90 × 216 × 64.5 mm
DIN-rail width	12 modules
Net weight	0.7 kg
Protection	IP20

Planning, Installation and Commissioning

Install the MDRC device on 35 mm DIN rail in a suitable distribution enclosure. Installation and commissioning must be performed by a qualified electrician. Isolate hazardous voltages before wiring, keep KNX SELV conductors separated from mains circuits, and follow the type-specific ABB wiring diagram and instructions.

Use only the documents listed below for RM/S2.1. ABB does not currently expose a confirmed standalone ETS package for this model, so no guessed or legacy application download is presented.