Other devices on the I/O bus

Room units


Comunicative room units (UI011UI012…)

The room unit has a knob for setting of temperature setpoint or setpoint correction, and a display. Its typical usage is for control of a HVAC unit or heating circuit. The room unit contains an internal temperature and humidity sensor, selected types (UI9…) also have a CO2 sensor. In the bottom there are two terminal bars, at some types there is only one. The terminals connect power and communication and for some types, also hardware inputs and outputs. The control unit is snapped on the base with terminals which is fixed to a flush-mount box or directly to the wall. See data sheets for details.

The room unit can be mounted directly to the wall if cable installation allows.


1 – operating modes

2 – fan stages

3 – turn – setpoint correction

4 – push – fan stage or operating mode setting



The units communicate over a 2-wire RS485 bus with Modbus protocol, same as all the other modules on the bus, and they can be connected on the same bus together with I/O modules. However, note that the response time may be slower with more units on the bus, it is advisable to use a separate bus for room units for that reason.

For installations where no user intervention is required, the room units are supplied also with no knob or with no knob nor display. In this version, they actually work as communicative sensors with additional I/Os (according to the type used). See data sheet for the complete overview and type names.


Communicative room units with blinds control (UX011,UX041)

The room units are derived from the UI… range, with extra blind control functionality. The room unit has five pushbuttons instead of the knob, and two triac outputs which control the motors using power relay modules ME200 (2 pcs. of 230 V / 5 A AC relays controlled by 24 V AC from the unit, in a small housing for flush-mount box installation).

Communicative controllers


Communicative room controllers with Modbus / RS485 (types UC102, UC200, UC300, etc.)

The controllers communicate over RS485 using Modbus, same as the other I/O modules, and they can be connected to the same bus. However, this is advisable only under following conditions:

  • their number is small (up to about 10), so that they do not slow down communication with the other I/O modules
  • the risk of bus short circuit is acceptable (most of the bus wiring goes outside of the panel and if there is a short circuit, communication with all the I/O modules is broken)
  • a connection on the process level is required, e.g. for change-over signals, heating / cooling demand signals etc.

In general, it is advisable to use a process station with more COM ports, and connect all room units and controllers to a separate bus. Even so, the last condition is met.

Note that the UC120 and UC220 (with 0..10 V output) use 24 V DC power only.


A communicative controller, derived from the UC… controllers, with blind control functionality.

All controllers can be supplied with no knob / display – please specify …/DK when ordering.


Connection of more UC102 controllers on the bus.


Communicative fancoil controllers FCR010, FC020

The fan coil controllers feature two communication interfaces: K2 for communication with the room unit UC010 (marked by the room unit symbol), and K1 for connection to a PLC or management station (marked by a bus symbol with controllers).

The room unit interface does not need any configuration, the room unit always has Modbus address 1. As the K2 bus length is several meters only, the cable type is not critical.

The K1 interface shall be connected according to the same rules which apply for the UC…. controllers.


Typical FCR010 connection. Details see the FCR010 data sheet.