User's Manual

Street Light Bridge Integrator’s Guide 37
channel, all the Street Light Bridge modules within a street lighting network
coordinate which frequencies they use. Multiple Street Light Bridge modules can
use a single RF channel. In addition, multiple RF channels can exist within a
single street lighting network.
A Street Light Bridge module identifies these channels through a pair of
configuration network variables (nciPriChs and nciSecChs), which define three
channels in the range 11..26, with default values for the primary channel of 25,
20, and 15, and default values for the secondary channel of 11, 17, and 26. The
two configuration network variables represent the primary (normal) and
secondary (alternate) LonTalk (ISO/IEC 14908-1) path, which allow the
transceiver to define a primary and a secondary channel for communications. If
communications fail on the primary channel, the Street Light Bridge module can
switch to the secondary channel. The secondary frequency is used when the
Segment Controller requests that the alternate path be used.
Important: For all Street Light Bridge modules within the street lighting
network, the set of defined primary channels must match for all Street Light
Bridge modules, and the set of defined secondary channels must match for all
Street Light Bridge modules. In general, the primary and secondary channels
should not be the same.
A Street Light Bridge module broadcasts a packet once, followed by a number of
repeats (the default number is 1; you can modify the nciPriRpt and nciSecRpt
configuration network variables to specify additional repeats) on each of the
configured RF channels. For each path, the product of the number of configured
channels and the repeat count plus one should not exceed 12. The default is 6
(three channels with one repeat). Thus, for three configured channels, you
should define no more than three repeats.
Signal Strength
The Segment Controller Power Line Repeating Analysis Web page shows device
signal strength and margin information. When a Street Light Bridge module is
used for power line repeating, the Web page shows power line signal strength
and margin information. When the Street Light Bridge module is used for RF
repeating (or both power line and RF repeating), you can also retrieve RF signal
strength and margin information; see
Analyzing a Power Line Repeating
Network
on page 54.
Defining the Media Access Protocol
Each Street Light Bridge module has its media access protocol pre-programmed
in the factory. For European street lighting networks, the Street Light Bridge
module uses the comité européen de normalisation electrotechnique
5
(CENELEC) EN50065-1 media access protocol for power line networks. For
other geographies, the CENELEC protocol is not used.
For device testing, or for power line networks that do not connect to public mains
power lines, you can decide to enable or disable the use of the CENELEC protocol
for a Street Light Bridge module. From the Segment Controller, you can change
5
European Committee for Electrotechnical Standardization