Communicative fan coil controller - MIDAM RFC01711
Communicative fan coil controller with three-stage fan speed and controlled heating/cooling operation. It can operate completely autonomously or be integrated into the topology of various higher-level SCADA systems. The suitable HMI for RFC01711 is the room unit RUC00011 or RGC000xx. Communication between the room unit and the controller is based on a proprietary protocol over a serial line.
- Three-stage fan speed control
- Controlled heating / cooling operation
- Ability to operate in autonomous mode
- Integration into SCADA systems
Function
The RFC01711 fan coil controller operates with a supply voltage of 24 VAC and simultaneously provides power to the room unit RUC00011 or RGC000xx. The controller communicates with the room unit using a proprietary protocol via a dedicated serial line. Room temperature and setpoint values transmitted from the room unit are processed using a PI control algorithm. PWM modulation is used to control radiator valves via the controller’s triac outputs. The controller is designed to operate in a non-aggressive environment and requires no maintenance throughout its lifetime. It can be mounted using the attached brackets on any flat surface (fan coil body, mounting panel) as well as on a standard DIN rail. The controller includes an internal real-time clock backed up by an internal battery. The clock allows setting a weekly schedule with six programs for each day. Control modes include Comfort, Setback, and Off. Valve operation can be configured as NO (normally open) or NC (normally closed). Fan speeds can be controlled automatically (according to the PID output or control deviation) or manually (if enabled during configuration). The controller includes two digital inputs for a presence sensor (access card reader, PIR sensor, etc.) and for a window contact or dew point sensor (which switches the system to the Off mode). The logic of these contacts can be configured in the controller settings. Status indication is provided by three LEDs: green PWR LED – power supply, red TX1 LED – RS485 communication transmitting data to the building bus, and red TX2 LED – RS485 communication transmitting data to the room unit. The controller features a native Modbus map (also for RUC00011/RGC000xx) with direct read and write functionality, available in a separate document. All settings and configuration parameters are also stored directly in the device’s Modbus registers.
Application
- Room control with four-pipe fan coil units
- Room control with two-pipe fan coil units
- Room control with cooling fan coils and radiators
- Room control with heating convectors and chilled panels
- Integration into SCADA systems
Configuration
The device can be configured using a tool provided by the manufacturer or by using a standard Modbus software tool that modifies the corresponding registers. In this way, various operating modes and user access levels can be configured. Device adjustments and configuration can also be performed later without the need for special tools, for example setting the setpoint, disabling or enabling buttons, control functions, etc.
Integration into a higher-level SCADA system
The RFC01711 can be integrated into a higher-level SCADA system directly via the Modbus RTU (RS485) bus.