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Siemens
RXB (KNX) application library
FNC Description of functions for FC-10, FC-11, FC-12
CM110385en_05
Building Technologies
Setpoint calculation
28 Feb 2009
6 Setpoint
calculation
6.1
Description
•
Each room controller has
9 different room temperature setpoints
:
One heating and cooling setpoint for the room operating modes
Comfort, Precomfort,
Economy
and
Protection
as well as a Frost limit value
.
•
The setpoints
– are
defined
in the tool during engineering.
– runtime-
adjusted
by the communication objects (DESIGO, Synco)
This does not apply to the
Protection
setpoints and the frost setpoint (page 33).
•
The setpoints are
shifted
–
Centrally
via KNX bus from the building automation and control system
(only
Comfort
,
Precomfort
and
Economy
).
–
Locally
via PPS2 by a room unit or a setpoint adjustment unit
(only
Comfort
and
Precomfort
).
– The controller controls the values internally to ensure that sensible periods are
adhered to between the various room operating modes.
•
The result is 8
present
setpoints.
•
The
effective room operating mode
selects one setpoint each for heating and
cooling from the 8 setpoints.
These are the
effective setpoints
to which the controller executes control.
Define
Shift
10
38
5
Z
4
0en
Comfort heating setpoint
Comfort cooling setpoint
Precomfort heating setpoint
Precomfort cooling setpoint
Economy heating setpoint
Economy cooling setpoint
Protection heating setpoint
Protection cooling setpoint
Local setpoint shift
Central setpoint shift heating
8
present
setpoints
Effective
heating setpoint SpH
Effective
cooling setpoint SpC
H
C
PPS2
KNX
Effective
room operating mode
Central setpoint shift cooling
Frost setpoint
KNX
KNX
KNX
KNX
PPS2
DI
KNX
KNX
(6.1.1)
(6.1.2)