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Siemens
QAX34.1 – Room unit with PPS2 interface
CA2N1645en_02
Building Technologies
30 Jun 2009
Commissioning notes
After an interrupt of the PPS2 interface the communication will only be re-established
when the connected controller polls the PPS2 addresses. The duration of the corre-
sponding cycle is:
RXA: 10 sec; RXB, RXL and RXC: 3 min; PX: 30 sec.
When the supply voltage is connected (via PPS2 interface) or when the controller initi-
ates a reset, the room unit initially responds as follows:
Step Function
Description
1
LCD test
All segments of the display activated for approx. 5 s.
2 Identification
by
controller
The display reads
until the controller identifies the
room unit as a PPS2 component.
3 Room
unit
ready for opera-
tion
1 second after identification by the controller, the room
unit is ready for operation.
If the room unit is connected to a L
ON
M
ARK
-compatible controller (DESIGO RX), the
display can be used as an aid to commissioning. If the RXT10 commissioning and ser-
vice tool initiates a wink command, the type of controller connected will be displayed on
the room unit. For example:
Controller type
Display
RXC21.1
RXC30.1
Operating notes
During operation and commissioning, the LCD display also indicates errors, as follows
Display Description
Error
type
C:
No communication with controller for more than 64 s
02:
Firmware version (e.g. Version 2.0)
D
Room temperature sensor outside range 0 ... 40 °C
S
Room unit not yet in list of PPS2 components
(during
controller start-up phase)
D
Controller does not recognize room unit type
D
Initial value after start-up, before the controller transmits a
signal
S
Controller transmits no valid T-value
S
S
Static error: The error code remains in the display until the cause of the error has been dealt with.
D
Dynamic error: The error code will be displayed instead of the room temperature for 5 s after
occurrence of the error. The display will then revert to normal. While the error persists, the error
code will be re-displayed each time the + or – key is operated. The setpoint can be adjusted by
pressing the key again.
All other error codes indicate hardware faults.
Response on start-up
Wink function display
with LON-devices
