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Siemens
RDU341 Basic Documentation
CE1P3172en
Building Technologies
2015-06-08
3.8 Multifunctional input, digital input
The thermostat has 2 multifunctional inputs X1 and X2
An NTC type sensor like 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 via parameters P38 + P39 for X1, P40 + P41 for X2.
The current temperature or state of the inputs X1/X2 is available on bus for
monitoring purposes.
The parameters can be set to the following values:
#
Function of
input
Description
Type
X1/X2
0
Not used
No function.
--
1
External / return
air temperature
Sensor input for external room temperature sensor or
return air temperature sensor to acquire the current
room temperature, or floor heating temperature sensor
to limit the heating output.
AI
KNX
R
Supply air
temperature
2
Heating / cooling
changeover
Sensor input for “Automatic heating / cooling change-
over” function.
A switch can also be connected rather than a sensor
(switch closed = cooling, see section 3.5).
With single-duct applications, the input changes over
the air sequence.
Heating / cooling changeover is also possible via bus.
In this case, the function must not be assigned to any
local input X1, X2, D1. See also section 3.5.
Diagnostic value 0
˚
C is displayed for closed contact /
100
˚
C for open contact, if a switch is connected.
AI /
DI
KNX
R
Window
state
3
Operating mode
switchover
Digital input to switch over the operating mode to
Economy.
If the operating mode switchover contact is active, user
operations are ineffective and “OFF” is displayed.
Operating mode switchover is also possible via bus.
In this case, the function must not be assigned to any
local input X1, X2. See also section 3.2.
DI
4
Dew point
monitor
Digital input for a dew point sensor to detect
condensation. Cooling is stopped if condensation
occurs.
DI
KNX
R
Enable elec-
tric heater
5
Enable electric
heater
Digital input to enable / disable the electric heater via
remote control.
Enable electric heater is also possible via bus.
In this case, the function must not be assigned to any
local input X1, X2. See also section 3.6.
DI
KNX
R