Echelon Lumewave CRD 3000 Street Light Bridge - Manual (Page 53)

Street Light Bridge Integrator’s Guide 43
minutes), the Segment Controller should report the outage so that network
management personnel can investigate and repair the outage.
Figure 10. An Example Street Lighting Network
These scenarios assume that both SLB A and SLB B have the same RF channel
lists (primary 25, 20, 15 and secondary 11, 17, 26) – an assumption that should
apply to nearly all street lighting networks. Also, these scenarios assume that
the network has good communications prior to device failure.
Scenario 1: Loss of SLB A
When SLB A fails (for example, it experiences a power outage), any
communications initiated by the Segment Controller cannot reach SLB B or the
street light.
At this point, SLB B determines that the RF channel is idle. After the channel
has been idle for 15 minutes, SLB B tunes to another channel from its configured
channel list. If that channel is also idle, SLB B cycles through all of its
configured channels to attempt to reestablish communications. SLB B cycles
through all of its defined channels until SLB A rejoins the network.
When SLB A becomes active, SLB A and SLB B negotiate a new primary channel
for communications. Because the two CRD 3000 Street Light Bridge modules are
likely not to be using the same channel at the same time when SLB A rejoins the
network, both cycle through their defined channels until communications are
established. By default, the cycle time is approximately 3 minutes for each
channel.
If SLB A had been offline for less than 15 minutes, RF communications would be
reestablished immediately because SLB B would not have switched from the
original channel and SLB A, after it becomes active, would use the same channel.
Scenario 2: Brief Loss of SLB B
If SLB B experiences a brief outage (less than 15 minutes), communications
between the Segment Controller and SLB B or the street light fail. When SLB B
becomes operational, RF communications are reestablished quickly as the devices
negotiate the use of the channel.