Integration Via Modbus - Siemens RDF302 Documentation

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Siemens
Building Technologies
 Changeover between heating and cooling mode (automatic via local sensor or
Modbus, or manually)
 Selection of applications via DIP switches or commissioning tool.
 Select operating mode via operating mode button on the thermostat
 1- or 3-speed fan control (automatically or manually)
 Display of current room temperature or setpoint in °C and/or °F
 Display of outdoor temperature or time of day via Modbus
 Minimum and maximum limitation of room temperature setpoint
 Button lock (automatically, manually or via Modbus)
 2 multifunctional inputs, freely selectable for:
– Operating mode switchover contact (keycard, window contact, etc.)
– Sensor for automatic heating / cooling changeover
– External room temperature or return air temperature sensor
– Dew point sensor
– Electric heater enable
– Fault input
– Monitor input for temperature sensor or switch state
 Advanced fan control function, e.g. fan kick, fan start, selectable fan operation
(enable, disable or depending on heating or cooling mode)
 "Purge" function together with 2-port valve in a 2-pipe changeover system
 Reminder to clean fan filters
 Floor heating temperature limitation
 Reload factory settings for commissioning and control parameters
 RS 485 Modbus (terminals +, - and REF) for communication with Modbus
compatible devices
2.4

Integration via Modbus

The RDF302 is a communicative thermostat with Modbus open protocol on RTU
(Remote Terminal Unit) mode enabling easy integration into BACS via RS-485.
The following Modbus functions are available:

Central controls of room operating modes, setpoints, fan speed and fan mode

Remote monitoring e.g. operating mode, control outputs, temperature sensor
or switch, etc.

Alarming, e.g. external fault contact, condensation, clean filter, etc.

Outside temperature or time of day via bus displayed on thermostat

Key button lock
Engineering and commissioning can be done using...
– local DIP switches / HMI
– via Modbus commissioning tool
RDF302 Basic documentation
Summary
CE1P3079en
07 Dec 20111