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Siemens
RDG400 Basic Documentation
CE1P3182en
Building Technologies
2015-05-20
4.9
Multifunctional input, digital input
The thermostat has 2 multifunctional inputs X1 and X2 and 1 digital input D1.
A sensor type NTC 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 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
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
2 Heating/cooling
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 Economy.
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
electric
heater
Digital input to enable/disable the electric heater via remote
control.
DI
DI
6 Fault
Digital input to signal an external fault
(example: electric heater overheat).
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.
DI
DI
Operational action of the contact can be changed between normally open (NO) and
normally closed (NC) 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: 1, 2 or 3 inputs can 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 details, refer to section 4.5.
