Operating Instructions

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Siemens RXB (KNX) Applications library CLC and RAD description of functions for CC-02 CM110384en_04
Building Technologies Control sequences 21 Sep 2010
8.2.6 Central/passive dewpoint monitoring
The dewpoint can be monitored in two ways:
A dewpoint sensor with a potential-free contact is connected directly to a digital input
of the room controller (see page 102).
Dewpoint sensor via bus.
The two inputs are OR-linked: If one is active, dewpoint alarm applies.
RXB... Room controller
EIB / KNX Dewpoint sensor
10384z102en
Room dewpoint alarm input
DI
OR
Room dewpoint alarm output
Since EIB dewpoint sensors are available from a variety of manufacturers, the name of
the EIB output communication object varies accordingly.
The following KNX input communication object is used to integrate a dewpoint sensor
connected to the KNX bus:
Room dewpoint alarm input (input communication object)
Flags
R W C T U
Type Receive timeout States
0 1 1 1 1 1.005
DPT_Alarm
Yes
0 = No alarm
1 = Alarm (condensation)
The dewpoint monitoring status (result of the OR operation) can be evaluated in the
building automation and control system using the following communication object.
Room dewpoint alarm output (output communication object)
Flags
R W C T U
Type Send heartbeat States
1 0 1 1 0 1.005
DPT_Alarm
Yes
0 = No alarm
1 = Alarm (condensation)
For dewpoint monitoring, a logic OR operation is applied to the locally connected
sensor and the bus sensor.
The result is used in the alarm object room dewpoint alarm output on the bus (see
10.13).
When parameterizing, note whether the contacts are NO or NC (see page 102).
Note the following for master/slave configurations:
Dewpoint sensor on master:
The sensor is evaluated locally
cooling valve closes.
This information is transmitted to the slaves.
– Dewpoint
sensor on slave:
The sensor is evaluated locally
cooling valve closes.
This information is NOT transmitted to the master and further slaves..
The controller immediately queries the dewpoint alarm input following a reset
(if configured accordingly and provided a dewpoint is integrated).
KNX
R
CO
Notes