Wiring the System
26
Siemens Building Technologies
Fire Safety & Security Products
09.2008
1
SPC Controller X-BUS Terminal Block
2
Expander Three
3
Expander Two
4
Expander One
Fig. 6
Open Loop (Spur) Configuration
7.1.2 Star
(Multi-drop) Configuration
The star cabling method is most effective with homes that are prewired with four-
core cable. These configurations allow for a maximum cable length of 200 metres.
A star configuration is established when multiple Expanders are wired back to the
same input channel of the X-BUS on the SPC Controller. See wiring configuration
in Fig. 7.
1
SPC Controller
2 - 4
Expanders
Fig. 7
Star Configuration
