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Siemens
RXB (KNX) application library
FNC Description of functions for FC-10, FC-11, FC-12 CM110385en_05
Building Technologies
Control sequences
28 Feb 2009
8.4.3
The electric reheater
In the case of the RXB22.1 room controller, the electric reheater is switched directly via
output Q44 (max. 1.8 kW resistive).
The controller output of the electric reheater can be disabled locally via a safety
thermostat connected to one of the hardware inputs. The alarm input and the way in
which it operates can be configured with the tool (see "Digital inputs", page 126).
When the safety thermostat trips, an alarm is generated, which is output via the
communication object
Alarm
(see page 134).
The "position" of the electric reheater is also mapped to the bus.
In S-mode, the following communication object is used for this purpose:
Heating output bus electric heating (Output communication object)
Flags
R W K T U
Type Send
heartbeat
Value
1 0 1 1 0 5.001
DPT_scaling
yes
0...100%
0 = 0%
255 = 100%
In LTE mode, the "position" of the electric reheater is transmitted as follows:
Heating output bus electric heating (Output)
Possible partner function blocks
Known partner
devices
ActPosSetpHeatStageB
Geographical zone
352 HVA
HVAC Valve Actuator
369 EHEA
Electric Heater Element Actuator
---
If the LTE bus information is not required, it can be disabled (see pages 90 and 143 for
notes on reducing the load on the bus).
HandyTool
See parameters in the last column of the following table.
Short name
Range
Basic setting
HandyTool
Heating outp bus el heating
0 = Disabled / Off
1 = Enabled / On
Disabled(0) *089
In applications involving an electric reheater, the latter can be disabled (e.g. for reasons
associated with tariff regulations).
The communication objects are as follows:
Enable electric heating (Input communication object)
Flags
R W K T U
Type Receive
timeout
Value
0 1 1 0 0 1.003
DPT_Enable
yes
0 = Disabled
1 = Enabled
Controller output
Safety thermostat
Desired output
KNX
R
CO
Reducing the bus load
Central disable signal
KNX
R
CO