Siemens RDG400 - Manual (Page 26)

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Siemens RDG100…/RDG110…/RDG140.../RDG160… Basic Documentation CE1P3182en
Building Technologies Functions 28 May 2009
4.9 Multifunctional input, Digital input
The thermostat offers two multifunctional inputs X1 and X2 and a digital input D1.
A sensor of type NTC like 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 for X1, P40 for X2, and P42 for D1.
# Function of input Description Type
X1/X2
Type
DI
0 Not used No function. -- --
1 External/Return
air temp.
Sensor input for external room temperature sensor or
return air temperature sensor to measure the current
room temperature, or floor heating temperature
sensor to limit the heating output.
Note: The room temperature is measured by the built-
in sensor if the floor heating limitation function is
enabled via parameter P51. AI
2 Heat/cool
changeover
Sensor input for automatic heating / cooling
changeover function.
A switch can also be connected rather than a sensor
(switch closed = cooling, see section 4.6). AI/(DI) DI
3 Operating mode
switchover
Digital input to switch over the operating mode to
Energy Saving.
If the operating mode switchover contact is active,
user operations are ineffective and “OFF” is displayed. DI DI
4 Dewpoint monitor Digital input for a dewpoint sensor to detect
condensation. Cooling is stopped if condensation
occurs. DI DI
5 Enable electrical
heater
Digital input to enable/disable the electrical heater via
remote control. DI DI
6 Fault Digital input to signal a fault.
If the input is active, “ALx” is displayed
(Alarm x, with x = 1 for X1, x = 2 for X2, x = 3 for D1).
Note: Fault displays do not influence the thermostat's
operation. They merely represent a visual signal.
Example: dirty air filter DI DI
Operational action can be changed between normally open (N.O.) and normally
closed (N.C.) via parameter P39, P41 (or P43 if it is a digital input).
Each input X1, X2 or D1 must be configured with a different function (1 … 5).
Exception: one or two or three inputs may be configured as alarm inputs (6)
X1 is factory-set to “External sensor” (1), X2 to “Heating/Cooling changeover” (2),
and D1 to Operating mode changeover (3).
For more information see section 4.5 “Applications”.