Siemens RDF302/VB User manual

RDF302, RDF302.B
RDF302/VB
Flush-mounted room thermostats with RS485
Modbus communications
RDF302, RDF302/VB, RDF302.B
Basic documentation
Edition 1.6
CE1P3079en
2022-06-17
Smart Infrastructure

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Contents
1. About this document...........................................................................4
1.1 Revision history .....................................................................................4
1.2 Reference documents............................................................................5
1.3 Before you start .....................................................................................5
1.3.1 Copyright...............................................................................................5
1.3.2 Quality assurance..................................................................................5
1.3.3 Document use / request to the reader ....................................................5
1.4 Target audience, prerequisites ...............................................................6
1.5 Glossary................................................................................................6
2. Summary..............................................................................................7
2.1 Types ....................................................................................................7
2.2 Ordering ................................................................................................7
2.3 Functions...............................................................................................7
2.4 Integration via Modbus...........................................................................8
2.5 Equipment combinations........................................................................9
2.6 Accessories...........................................................................................9
3. Functions ...........................................................................................10
3.1 Temperature control.............................................................................10
3.2 Operating modes ................................................................................. 11
3.2.1 Different ways to influence the operating mode ....................................12
3.3 Room temperature setpoint..................................................................13
3.3.1 Description ..........................................................................................13
3.3.2 Setting and adjusting setpoints ............................................................14
3.4 Applications overview ..........................................................................16
3.4.1 Applications for fan coil systems *)........................................................17
3.4.2 Applications for universal systems *).....................................................18
3.4.3 Applications for heat pump systems *) ..................................................19
3.5 Additional functions..............................................................................20
3.6 Control sequences...............................................................................23
3.6.1 Sequences overview (setting via parameter P01).................................23
3.6.2 2-pipe fan coil unit................................................................................24
3.6.3 2-pipe fan coil unit with electric heater..................................................25
3.6.4 4-pipe fan coil unit................................................................................27
3.6.5 Chilled / heated ceiling and radiator applications..................................29
3.6.6 Compressor applications .....................................................................29
3.6.7 Setpoints and sequences.....................................................................30
3.7 Control outputs ....................................................................................32
3.7.1 Overview .............................................................................................32
3.7.2 Control outputs configuration (setting via DIP switches or Modbus
commissioning tool).............................................................................33
3.8 Fan control ..........................................................................................34
3.9 Multifunctional input, digital input..........................................................37
3.10 Handling faults.....................................................................................39
3.11 Modbus RTU mode..............................................................................40
3.11.1 Fault function on Modbus.....................................................................40
3.12 Communication objects........................................................................41

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3.12.1 Overview .............................................................................................41
3.12.2 Description of communication objects ..................................................42
3.13 Control parameters ..............................................................................47
3.13.1 Parameter setting via local HMI............................................................47
3.13.2 Parameter setting / download via Modbus communication tool .............47
3.13.3 Parameters of the “Service level” .........................................................48
3.13.4 Parameters of the "Expert level with diagnostics and test"....................49
4. Handling.............................................................................................51
4.1 Mounting and installation .....................................................................51
4.2 Commissioning ....................................................................................52
4.3 Operation.............................................................................................53
4.4 Disposal ..............................................................................................54
5. Connection.........................................................................................55
5.1 Connection terminals ...........................................................................55
5.2 Connection diagrams ...........................................................................56
6. Mechanical design.............................................................................57
6.1 General ...............................................................................................57
6.2 Dimensions..........................................................................................58
7. Technical data....................................................................................59

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1. About this document
1.1 Revision history
Edition
Date
Changes
Section
Pages
1.6
2022-06-17
Add one more value of P06
3.12.2
3.13.3
44
48
1.5
2020-12-01
Update function code description
3.12.2
45-49
1.4
2020-02-21
Add product RDF302/VB related information
1.2
1.4
1.5
2.1
2.2
2.4
3.7.1
3.11
3.12.1
4.3
6.1
4
7
7
8
8
9
34
42
43
55
59
1.3
2018-12-04
Add product RDF302.B related information
1.1, 1.2
1.4, 1.5
2.1, 2.2
2.4
3.2
3.2.1
3.5
3.6.4
3.7.1
3.9
3.11,
3.11.1
3.12
3.12.2
3.13.4
4.1
4.3
5.1
6.1
7
4
6
7
8
12
13-14
21
28
33
38
41
42
46
51
52
54
56
58
61
1.2
2017-12-08
Update communication objects
Add information about operating mode.
3.12.1
3.12.2
3.2
3.2.1
3.12.2
42
43-44
12
13
46
1.1
2014-10-09
As per new software update and compliance update,
as well as other corrections
2.5
3.4
3.6
3.7.1
4.1
4.4
7
9
16
23
32
51
54
59
1.0
07,12.2011
First edition

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1.2 Reference documents
Subject
Ref
Doc No.
Description
Modbus Manual
[1]
MODBUS over serial line specification and implementation guide
(http://www.modbus.org)
RDF302, RDF302/VB,
RDF302.B Room
Thermostat with Modbus
Interface
[2]
CB1N3079
Data Sheet
[3]
CB1B3079
Operating Instructions
[4]
CB1M3079
Installation Instructions
SEZ50MB (RWD Modbus)
[5]
CB1N3099
Data Sheet
[6]
CB1P3099
Basic Documentation
1.3 Before you start
1.3.1 Copyright
This document may be duplicated and distributed only with the express permission
of Siemens, and may be passed only to authorized persons or companies with the
required technical knowledge.
1.3.2 Quality assurance
This document was prepared with great care.
•The contents of this document is checked at regular intervals
•Any corrections necessary are included in subsequent versions
•Documents are automatically amended as a consequence of modifications and
corrections to the products described
Please make sure that you are aware of the latest document revision date.
If you find lack of clarity while using this document, or if you have any criticisms or
suggestions, please contact the Product Manager in your nearest branch office.
The addresses of the Siemens Regional Companies are available at
www.buildingtechnologies.siemens.com.
1.3.3 Document use / request to the reader
Before using our products, it is important that you read the documents supplied
with or ordered at the same time as the products (equipment, applications, tools,
etc.) carefully and in full.
We assume that persons using our products and documents are authorized and
trained appropriately and have the technical knowledge required to use our
products as intended.
More information on the products and applications is available:
•On the intranet (Siemens employees only) at
https://workspace.sbt.siemens.com/content/00001123/default.aspx
•From the Siemens branch office near you
www.buildingtechnologies.siemens.com or from your system supplier
•From the support team at headquarters [e-mail] if
there is no local point of contact
Siemens assumes no liability to the extent allowed under the law for any losses
resulting from a failure to comply with the aforementioned points or for the
improper compliance of the same.

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1.4 Target audience, prerequisites
Product & sales managers, distributors, re-sellers & OEM customers who use
RDF302, RDF302/VB and RDF302.B room thermostats in the RS485 Modbus RTU
network.
Since Modbus protocol has been well known for years in the industry, this
document will explain the operations related to RDF302, RDF302/VB and
RDF302.B Modbus units. e.g. the unit setup, available settings and their
applications. And, users should have the general knowledge of HVAC systems and
local electrical installation regulations where RDF302, RDF302/VB and RDF302.B
units are employed.
For reference documentation, see section 0.
1.5 Glossary
The inputs, outputs and parameters of an application can be influenced in various
ways. These are identified by the following symbols in this document:
Term
Description
DTE
Data Terminal Equipment
Modbus master
A MODBUS device, which is able to access data in one or more
connected MODBUS Slave
Modbus slave
A MODBUS device, which is able to respond to requests from a
single MODBUS master
Pxx
Parameters of the device where xx = 00, 01, 02, etc.
RDF Modbus
The name of RDF302, RDF302/VB and RDF302.B providing
RS485 Modbus communicative
RTU
Remote Terminal Unit = Standard MODBUS transmission mode
The communication objects of the RDF302, RDF302/VB and RDF302.B
thermostats are described accordingly.
A list of the parameters is shown in section 3.13.

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2. Summary
2.1 Types
1) Selectable: ON/OFF or 3-position
2.2 Ordering
For input and output difference between RDF302, RDF302/VB and RDF302.B, see
Connection terminals.
Order valve actuators separately.
2.3 Functions
Fan coil units via ON/OFF outputs:
•2-pipe system *
•2-pipe system with electric heater
•4-pipe system
Chilled / heated ceilings (or radiators) via ON/OFF outputs:
•Chilled / heated ceiling *
•Chilled / heated ceiling with electric heater
•Chilled / heated ceiling and radiator / floor heating
Compressors: via ON/OFF control
•1-stage compressors in DX type equipment
•1-stage compressors in DX type equipment with electric heater
* with both ON/OFF or modulating control output
The room thermostats are delivered with a fixed set of applications.
The relevant application is selected and activated during commissioning using one
of the following tools:
•Local DIP switch and HMI
•Modbus commissioning tools
•Operating modes: Comfort, Economy and Protection
•ON/OFF or 3-position control outputs (relay)
•Output for 3-speed or 1-speed fan
•Automatic or manual heating / cooling changeover
Product no.
Stock no.
Operating voltage
Control outputs
Suitable
conduit box
Color
3-pos
ON/OFF
RDF302
S55770-T238
AC 230 V
1 1)
2 1)
square
White
RDF302/VB
S55770-T428
AC 230 V
1 1)
2 1)
square
Black
RDF302.B
S55770-T416
AC 230 V
1 1)
2 1)
square
White
Product no.
Stock no.
Designation
RDF302
S55770-T238
Modbus Room thermostat
RDF302.B
S55770-T416
Basic Modbus room thermostat
RDF302/VB
S55770-T428
Modbus Room thermostat
Use
Features

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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
Functions

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2.5 Equipment combinations
Description
Product no.
Data sheet
Cable temperature sensor or
changeover sensor
cable length 2.5 m
NTC (3 kat 25 °C)
QAH11.1
1840
Room temperature sensor
NTC (3 kat 25 °C)
QAA32
1747
Cable temperature sensor
cable length 4 m
NTC (3 kat 25 °C)
QAP1030/UFH
1854
Condensation monitor / Dew point
monitor
QXA2601 /
QXA2602 /
QXA2603 /
AQX2604
3302
Electromotoric ON / OFF actuator
SFA21...
4863
Electromotoric ON / OFF valve and
actuator
(only available in AP, UAE, SA and IN)
MVI… / MXI…
A6V11251892
Zone valve actuator
(only available in AP, UAE, SA and IN)
SUA…
4832
Thermal actuator (for radiator valves)
STA23...
4884
Thermal actuator
(for small valves 2.5 mm)
STP23...
4884
Electrical actuator, 3-position
(for radiator valves)
SSA31...
4893
Electrical actuator, 3-position
(for 2- and 3-port valves / V…P45)
SSC31…
4895
Electrical actuator, 3-position
(for small valves 2.5 mm)
SSP31…
4864
Electrical actuator, 3-position
(for small valves 5.5 mm)
SSB31...
4891
Electrical actuator, 3-position
(for small valves 5.5 mm)
SSD31...
4861
Electromotoric actuator, 3-position
(for small valves 5.5 mm)
SQS35…
4573
Note:
For the maximal number of actuators in parallel, refer to information in the data
sheets of the selected actuators and to this list, depending on which value is lower:
•Parallel operation of max 6 SS… actuators (3-pos) is possible.
•Parallel operation of max 10 ON / OFF actuators is possible.
•Parallel operation of SQS35 is not possible.
2.6 Accessories
Description
Product no. / SSN
Data sheet
Changeover mounting kit
(50 pcs / package)
ARG86.3
N3009
Plastic mounting spacer for flush
mount thermostats to increase the
headroom in the conduit box
by 10 mm
ARG70.3
N3009
ON / OFF actuators
3-position actuators

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3. Functions
3.1 Temperature control
Setting of the control parameters (P01, etc., mentioned throughout the document)
is described in section 3.13.
The thermostat acquires the room temperature via built-in sensor, external room
temperature sensor (QAA32), or external return air temperature sensor (QAH11.1),
and maintains the setpoint by delivering actuator control commands to heating
and/or cooling equipment. The following control outputs are available:
•ON/OFF control (2-position)
•Modulating PI/P control with 3-position control output (only for 2-pipe
applications)
The switching differential or proportional band is 2 K for heating mode and 1 K for
cooling mode (adjustable via parameters P30 and P31).
The integral action time for modulating PI control is 5 minutes (adjustable via
parameter P35).
The display shows the acquired room temperature or the Comfort setpoint, selecta-
ble via parameter P06. The factory setting displays the current room temperature.
Use parameter P04 to display the room temperature or setpoint in °F rather than
°C as needed.
The acquired room temperature (internal or external sensor) is also available as
information on the Modbus.
•With automatic changeover or continuous heating / cooling, symbols /
indicate that the system currently heats or cools (heating or cooling output is
activated).
•With manual changeover (P01 = 2), symbols / indicate that the system
currently operates in heating or cooling mode. Thus, the symbols are displayed
even when the thermostat operates in the neutral zone.
Concurrent display of the current temperature or setpoint in °C and °F (parameter
P07 = 1) is possible on the thermostats.
The outside temperature can be displayed on the room thermostat by setting
parameter P07 = 2. This temperature value has only information character which
comes from the master device in the Modbus network.
Time of day via Modbus can be displayed on the room thermostat by setting
parameter P07 = 3 or 4. The display format is either in 12- or in 24-hour format.
The information can be received from a master device in the Modbus network.
General note:
Parameters
Temperature control
Display
Room temperature
/
Concurrent display of
°C and °F
Outside temperature
Time of day

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3.2 Operating modes
The thermostat's operating mode can be influenced in different ways. e.g.
operating mode button, switch over contact, Modbus, etc. Specific heating and
cooling setpoints are assigned to each operating mode.
The operating mode can be selected via Modbus.
•If a bus command is received via MODBUS for either COMFORT or
ECONOMY operating mode, the symbol of the selected operating mode
will be displayed.
i.e. either COMFORT or ECONOMY symbol only
•If a bus command is received for PROTECTION mode, the AUTO TIMER
symbol ( ) will be displayed and all key buttons will be de-activated.
i.e. both PROTECTION and AUTO TIMER symbols
The thermostat returns the effective room operating mode on the Modbus.
The following operating modes are available:
In Comfort mode, the thermostat maintains the Comfort setpoint. This setpoint can
be defined via parameters P8, P9 and P10.
Also, it can be locally adjusted via the +/- buttons or remotely via Modbus.
In Comfort mode, the fan can be set to automatic or manual fan speed: Low,
medium or high.
A preset setpoint in economy mode can be defined via parameters P11 and P12.
The thermostat switches to Economy mode when...
–the operating mode button is pressed (only possible if parameter P02 is set to 2)
–Economy is sent via Modbus
–an operating mode switchover contact (e.g. keycard contact presence detector,
window contact) is active.
The contact can be connected to multifunctional input X1, X2.
Set parameter P38 / P40 to 3 (P02 is irrelevant) *)
–"Window state" is sent via Modbus
*) Operating mode switchover: Only one input source must be used, either local
input X1/X2 or Modbus.
User operations are ineffective and “OFF” is displayed if the operating mode
switchover contact is active, or if "Window state" is sent via Modbus. The
parameters related to X1 and X2 input functions are not applicable to
RDF302.B.
In Protection mode, the system is...
–protected against frost (factory setting 8 °C, can be disabled or changed via
P65)
–protected against overheating (factory setting OFF, can be enabled or changed
via P66)
No other operating mode can be selected locally if Protection mode is commanded
via Modbus. is displayed.
Room operating mode:
Preselection
Room
operating mode: State
Comfort
Economy
Window state
Note:
Protection

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3.2.1 Different ways to influence the operating mode
The operating mode can be influenced by different interventions. The table below
shows the priorities of different interventions. (i.e. lower number higher priority)
Priority
Description
Remark

Commissioning
In parameter setting mode (highest priority), you can
always command an operating mode independent of
all other settings or intervention via Modbus and local
input.
If P02 changed by Modbus, the operating mode will
jump to Protection mode, in all cases, after the
update.

Operating mode
switchover
contact
If the contact is closed, the operating mode changes
to Economy. This overrides the operating mode on
the thermostat.

"Window state"
via Modbus
"Window state" sent via Modbus has the same effect
as the operating mode switchover contact.
Note: Only one input source must be used, either local input X1/X2 or
Modbus. RDF302.B does not have inputs X1 and X2.

Operating mode
via Modbus
The operating mode can be changed via Modbus
Note: Operating mode button is disabled if Protection
mode is commanded via Modbus. If a bus command
is received via MODBUS for either COMFORT or
ECONOMY operating mode, the symbol of the
selected operating mode will be displayed.
i.e. either COMFORT or ECONOMY symbol only
If a bus command is received for PROTECTION
mode, the AUTO TIMER symbol ( ) will be
displayed and all key buttons will be de-activated.
i.e. both PROTECTION and AUTO TIMER symbols

Operating mode
button
The user can switch the operating mode via the
operating mode button unless a key lock command
received from the Modbus before.
Note: Higher priority commands can override the lower priority’s
command. If operating mode is set via Modbus, the unit will indicate by
flashing “OFF” when OpMode button pressed by users.
The operating mode can be selected locally via the operating mode button.
The behavior of the operating mode button (user profile) can be defined via
parameter P02, factory setting is P02 = 1.
P02
Without time
schedule
Description
1
→
•Switching manually between 2modes, Economy is
not available (factory setting)
•Suited for hotel guest rooms or commercial
buildings.
2
→ →
•Switching manually between 3modes
•Suited for homes and rooms where manual
switching to Economy mode is desired
Priority of operating
mode interventions
Availability of Economy
mode

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The thermostat can be forced into Economy mode (e.g. when a window is opened,
when a presence detector signals "no one present", when the keycard of a hotel
room is withdrawn, etc). The contact can be connected to multifunctional input X1,
X2. Set parameter P38, P40 to 3.
The function is also available via the Modbus signal "Window state",
Note: Only one input source must be used, either local input X1/X2 or Modbus.
User operations are ineffective and “OFF”is displayed if the operating mode
switchover contact is active, or if "WindowContact" is sent via Modbus. RDF302.B
does not have inputs X1 and X2.
3.3 Room temperature setpoint
3.3.1 Description
The factory setting for the Comfort basic setpoint is 21 °C and can be changed in
the thermostat’s EEPROM via parameter P08 or via Modbus with communication
object "Comfort basic setpoint". The last intervention always wins.
The Comfort setpoint can be adjusted via the +/-buttons,
or via Modbus from a remote device like a touch panel or master unit, etc.
The last intervention always wins.
If the “Temporary setpoint” function is enabled via parameter P69, the Comfort
setpoint adjusted via the + / - buttons or via Modbus is set back to the Comfort
basic setpoint stored in P08 when the operating mode changes.
For energy saving purposes, the setpoint setting range can be limited to minimum
(P09) and maximum (P10).
•If the minimum limit P09 is set lower than the maximum limit P10, both heating
and cooling are adjustable between these 2 limits
•For heating or cooling applications (e.g. 2-stage):
–The setting range in cooling mode is from P09…40 °C in place of 5…40 °C
–The setting range in heating mode is from 5…P10 °C in place of 5…40 °C
•For heating and cooling applications (e.g. 4-pipe):
–The cooling and heating setpoint are adjustable
–The setting range in cooling mode is from P09…40 °C in place of 5…40 °C
–The setting range in heating mode is from 5…P10 °C in place of 5…40 °C
Examples
2-pipe heating OR cooling
4-pipe heating AND cooling
P09 < P10
Cooling setpoint adjustable 18…25 °C
Heating setpoint adjustable 18…25 °C
Cooling setpoint adjustable 18…25 °C
Heating setpoint adjustable 18…25 °C
Operating mode
switchover contact
(window contact)
Room operating mode:
Window State
Comfort mode
Temporary setpoint
Setpoint limitation
P09 < P10
P09 ≥P10

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P09 ≥P10
Cooling setpoint adjustable 25…40 °C
Heating setpoint adjustable 5…21 °C
Use control parameters P11 and P12 to adjust the Economy mode setpoints.
The heating setpoint is factory-set to 15 °C, and the cooling setpoint to 30 °C.
Use control parameters P65 and P66 to adjust the Protection mode setpoints.
The heating setpoint is factory-set to 8 °C (frost protection) and to OFF for cooling.
If a setpoint (Economy or Protection) is set to OFF, the thermostat does not control
the room temperature in the corresponding mode (heating or cooling).
This means no protective heating or cooling function and thus risk of frost in
heating mode or risk of over-temperature in cooling mode!
The Economy setpoints are accessible at the service level (P11, P12); the
Protection setpoints at the expert level (P65, P66).
3.3.2 Setting and adjusting setpoints
Room temperature setpoints can be
–set during commissioning
–adjusted during runtime
The source can be via
–local HMI
–a Modbus commissioning tool
–a Modbus master unit
The thermostat stores the setpoints
–in EEPROM in the form of parameters
The table below shows the interrelations:
Economy mode
Protection mode
Caution
Room temperature:
Comfort setpoint

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The current setpoint (used by the thermostat for temperature control) is available
on the Modbus for use in the central control unit.
•Changes via the local HMI or via tool have the same priority (last always wins)
•Setting the Comfort basic setpoint will reset the runtime Comfort setpoint to the
basic setpoint
•The resulting (current) setpoint heating and cooling is limited by the Protection
setpoint; if Protection setpoint is OFF, then minimum 5 °C and maximum 40 °C
are used
•The resulting setpoints for cooling and heating of the same operating mode have
a minimum distance of 0.5 K between them
Room temperature:
Current setpoint
General notes:
Notes on setpoint
adjustment

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3.4 Applications overview
The thermostats support the following applications, which can be configured using
the DIP switches inside the front panel of the unit or a Modbus commissioning tool.
All DIP switches need to be set to OFF (factory setting) to select an application via
commissioning tool.
Remote configuration, via commissioning tool (factory
setting)
DIP switches
See also…
•section 3.4.1 “Applications for fan coil systems”
•section 3.4.2 “Applications for universal systems”
•section 3.4.3 “Applications for heat pump systems”
•section 3.6.5 “Universal applications”
•section 3.6.6 “Compressor applications”.
Remote configuration

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3.4.1 Applications for fan coil systems *)
Application and output signal, DIP switches, diagram
•2-pipe fan coil unit ON/OFF
(heating or cooling)
1
ON
2 3
•2-pipe fan coil unit with electric
heater ON/OFF
(heating or cooling)
1
ON
2 3
3076D 20
(B1)
M1
V1
T
B2
T
T
(B1)
V1
M1
3171D 21
T
B2
E1
T
(B1)
T
(B1)
•2-pipe fan coil unit 3-position
(heating or cooling)
1
ON
2 3
•4-pipe fan coil unit ON / OFF
(heating and cooling)
1
ON
2 3
3076D 20
(B1)
M1
V1
T
B2
T
T
(B1)
T
V2
V1
M1
3076D 22
(B1)
T
(B1)
V1 Heating or heating / cooling valve actuator
B1 Return air temperature sensor or external room
temperature sensor (optional)
V2 Cooling valve actuator
B2 Changeover sensor (optional)
E1 Electric heater
M1 3- or 1-speed fan
*) RDF302.B does not have inputs X1 and X2, so sensor B1 and B2 are not
included in RDF302.B application.

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3.4.2 Applications for universal systems *)
Application and output signal, DIP switches, diagram
•Chilled / heated ceiling ON / OFF
(heating or cooling)
1
ON
2 3
Chilled / heated ceiling with electric
heater
(heating or cooling) ON / OFF
1
ON
2 3
3191S11
N1T
B1
T
B2
T
D3
V1
3191S12
N1T
E1
B1
T
B2
T
D3
V1
•Chilled / heated ceiling 3-position
(heating or cooling)
1
ON
2 3
•Chilled ceiling and radiator ON / OFF
(heating and cooling)
1
ON
2 3
3191S11
N1T
B1
T
B2
T
D3
V1
3191S13
N1T
B1
T
D3
V2
V1
V1 Heating or heating / cooling valve actuator
B1 Return air temperature sensor or external room
temperature sensor (optional)
V2 Cooling valve actuator
B2 Changeover sensor (optional)
E1 Electric heater
D3 Dewpoint sensor
*) RDF302.B does not have inputs X1 and X2, so sensor B1 and B2 are not
included in RDF302.B application.

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3.4.3 Applications for heat pump systems *)
Application and output signal, DIP switches, diagram
•1-stage compressor ON / OFF
(heating or cooling)
1
ON
2 3
•1-stage compressor with electric
heater
(heating or cooling) ON / OFF
1
ON
2 3
3181S31
N1
T
B1
T
D3
3181S32
N1T
E1
B1
T
D3
•1-stage compressor ON / OFF
(heating and cooling)
1
ON
2 3
3181S35
N1
T
B1
T
D3
N1 Thermostat
Terminal Y11: Heating or heating / cooling
Terminal Y21: for cooling (H &C)
B1 Return air temperature sensor or external room
temperature sensor (optional)
E1 Electric heater
D3 Dewpoint sensor
*) RDF302.B does not have inputs X1 and X2, so sensor B1 and B2 are not
included in RDF302.B application.

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3.5 Additional functions
The heating / cooling changeover information can be received via Modbus. This is
only possible if the control sequence is set to automatic heating / cooling
changeover (parameter P01 = 3) and no local input X1, X2 is assigned with this
function.
Note: RDF302.B does not have inputs X1 and X2.
In the absence of the required information (e.g. due to problems with data
communication, power failure, etc.), the thermostat operates in the last valid room
operating mode (heating or cooling).
If a cable temperature sensor (QAH11.1 + ARG86.3) is connected to X1 / X2, and
parameter P38 / P40 is =2, the water temperature acquired by the changeover
sensor is used to change over from heating to cooling mode, or vice versa.
•When the water temperature is above 28 °C (adjustable via parameter P37),
the thermostat changes over to heating mode.
It stays in heating mode until the temperature falls below 16°C (adjustable via
parameter P36)
•When the water temperature is below 16 °C (P36), the thermostat changes
over to cooling mode.
It stays in cooling mode until the temperature rises above 28°C (P37).
•If the water temperature is between the 2 changeover points immediately after
power-up (inside the hysteresis), the thermostat starts in previous mode.
The water temperature is acquired at 30-second intervals and the operating state is
updated accordingly.
M
Operating mode
Cooling mode
Tw
Water temperature
Heating mode
The QAH11.1 cable temperature sensor for automatic heating / cooling changeover
can be replaced by an external switch for manual, remote changeover:
Contact open
→heating mode
Contact closed
→cooling mode
The sensor or switch can be connected to input terminal X2 or X1, depending on
the commissioning of the inputs (P38, P40).
See also section 3.9 “Multifunctional input”.
•Manual heating / cooling changeover means selection via changeover button on
the thermostat by repeatedly pushing the button until the required mode is
shown on the display (automatic changeover is done via an external sensor /
switch connected to X1, X2, or D1)
•If manual heating / cooling changeover is commissioned (P01 = 2), then heating
/ cooling mode cannot be changed via changeover sensor / switch; it will remain
in the last mode as selected locally via button.
Heating / cooling
changeover via
Modbus
Heating/cooling
changeover
Automatic heating /
cooling changeover via
changeover sensor
Changeover switch
Manual heating /
cooling changeover