Integration Via Modbus - Siemens RDF302/VB Manual

Functions
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• Backlit display
• AC 230 V operating voltage
• Room temperature control via built-in temperature sensor or external room
temperature / return air temperature sensor
• 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
• Key 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, RDF302/VB and RDF302.B are 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 lock
Engineering and commissioning can be done using...
– local DIP switches / HMI
– via Modbus commissioning tool
RDF302 Basic documentation CE1P3079en
2022-06-17