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Siemens RDG400KN Basic documentation CE1P3192en
Building Technologies Functions 20 Jul 2010
3.8 Multifunctional input, digital input
The thermostat has 2 multifunctional inputs X1 and a digital input D1.
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, and P42 + P43 for D1.
The current temperature or state of the inputs X1 and D1 is available on bus for
monitoring purposes.
The parameters can be set to the following values:
# Function of
input
Description Type
X1
Type
DI
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.
Note: The room temperature is acquired by the built-in
sensor if the floor temperature limitation function is
enabled via parameter P51.
AI --
KNX
R
Supply air
temperature
Heating/
cooling
changeover
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 ap
plications, the input changes over
the air sequence;
With single-duct with heating / cooling coil
applications, the input changes over the water
sequence (heating/cooling coil)
Heating / cooling changeover is also possible via bus.
("Supply air temperature" for changeover air, "Heating/
cooling changeover" for changeover water)
In this case, the function must not be assigned to any
local input X1, X2, D1. See also section 3.5.
Diag
nostic value 0 ˚C is displayed for closed contact /
100 ˚C for open contact, if a switch is connected.
AI /
DI
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, D1. See also section 3.2.
DI DI
4 Dew point
monitor
Digital input for a dew point sensor to detect
condensation. Cooling is stopped if condensation
occurs.
DI DI
KNX
R