Siemens Desigo RXB Technical Manual page 76

Engineering notes
Mounting instructions
Installation
Warning
STOP
Commissioning
Start-up
characteristics
4/8
Siemens
Building Technologies
The room unit receives its power from the connected controller via the PPS2 interface
(low voltage, SELV).
Only one room unit can be connected to an RX... room controller.
When connecting a room unit to a PXC... automation station, the room unit must be
Address 1 (this address is permanently programmed in the room unit).
The room unit must be connected to the room controller with a two-core twisted pair
cable. See the relevant installation guide (RXC: CA110334; RXB & RXL: CM110381;
RXA: CA2Z3884). Unscreened cable may be used.
 The device is suitable both for surface mounting and for installation in a recessed
conduit box
 The unit should not be mounted in recesses, shelving, behind curtains or doors or
above or near direct heat sources
 Avoid direct sun and draughts
 The conduit must be sealed on the device side, as currents of air in the conduit can
affect the sensor reading
 The admissible ambient conditions must be observed.
 Mounting instructions are enclosed with the device.
 A set of fixing accessories is enclosed with the device.
Local installation regulations must be observed.
The equipment is not protected against accidental connection to AC 230 V.
After an interruption of the connection to the PPS2 interface, communication is only
re-established when the connected room controller next polls the PPS2 addresses.
The cycle times are as follows:
RXA: 10 seconds; RXB, RXL, and RXC: 3 minutes; PX: 30 seconds
When the supply voltage is connected (via the PPS2 interface) or in the event of a reset
via the room controller, the following routine is executed in the room unit:
Step Function
1 LCD test
2 Identification
by controller
3 Ready for
operation
QAX34.3 – Room unit with PPS2 interface
Description
All segments of the display module are operated for
approx. 3 s
Until the controller recognizes the room unit as a PPS2
user, the display reads:
1 s after recognition by the controller, the room unit is
ready for operation
CM2N1640en_04
30 Jun 2009