Siemens RDF800KN Series User Manual

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Siemens RDF800KN.., RDF800KN/VB, RDD810KN/NF Basic documentation CE1P3174en
Smart Infrastructure 2020-02-21
3.9 Multifunctional input, digital input
The thermostat has two multifunctional inputs X1 and X2. An NTC type sensor,
such as the QAH11.1 (AI, analog input) or a switch (DI, digital input) can be
connected to the input terminals. The functionality of the inputs can be configured
using P38 or P39 for X1 and P40 or P41 for X2.
The current temperature or the state of inputs X1 or X2 is available on bus for
monitoring purposes.
The parameters can be set to the following values:
No. Function of
input
Description Type
X1/X2
RDF.. RDD..
0 Not used No function. -- ü ü
1 External/return
air temperature
Input for external room temperature sensor
or return air temperature sensor to acquire
the current room temperature, or for floor
heating temperature sensor to limit the
heating output.
Note: The room temperature is acquired by
the built-in sensor if the floor temperature
limitation function is enabled via P51.
AI ü ü
Heating/
Cooling
changeover
2 Heating/cooling
changeover
Sensor input for "Automatic heating/cooling
changeover" function.
A switch, rather than a sensor, can also be
connected.
Note: A closed switch always means
cooling; this cannot be changed. See
section 3.5.
Heating/cooling changeover is also
possible via the bus. In this case, the
function must not be assigned to local input
X1, or X2. See section 3.5.
Diagnostic value displays one of the
following:
· 00 for closed contact
· 100 for open contact, if a switch is
connected.
AI/DI ü
Window
state
3 Window contact Window contact input to switch the
operating mode to Protection.
If the window contact is open, user
operations have no impact and OFF
displays.
Window contact is also possible using the
bus. In this case, the function must not be
assigned to local input X1 or X2. See
section 3.2.1.
DI ü ü
4 Dew point
monitor
Digital input for a dew point sensor to
detect condensation. Cooling is stopped if
condensation occurs.
DI ü

Siemens RDF800KN Series Specifications

General

Brand	Siemens
Model	RDF800KN Series
Category	Thermostat
Language	English