Echelon SmartServer 2.2 - Manual (Page 228)

SmartServer 2.2 User’s Guide 229
devices relay the messages to the repeating devices further down the
power line until the message reaches the target device. In this mode,
the SmartServer continuously attempts to discover and optimize the
repeating chains used to communicate messages from the
SmartServer to the devices on the network.

On (Static Proxy Chains). Same as On with Automatic
Discovery, except that the SmartServer does not continuously
discover and optimize the repeating chains, which increases the
available bandwidth on the power line repeating network for
operational traffic.
Notes: To use power line repeating, application device repeating must be
implemented on your L
ON W ORKS devices by the device manufacturers.
See your Echelon sales representative for more information.
To use power line repeating, you must also set the SmartServer to
standalone mode. See the previous section, Configuring a L
ON W ORKS
Network, for how to do this. Power line repeating is not compatible with
LNS mode.
For more information on managing a power line repeating network, see
the SmartServer 2.2 Power Line Repeating Network Management Guide.
Maximum Number
of Priority Slots Displays the maximum number of priority slots available on the channel.
Priority slots may be used by the critical devices on a network that use
priority messaging.
With priority messaging, the device with the highest priority sends its
packet before any other devices can send theirs. This is accomplished by
assigning each priority device a time (priority) slot where it can transmit
before all other lower priority and non-priority devices. These time slots
consume network bandwidth; therefore, priority messaging should only be
used for critical devices and data.
Use Round Trip
Delay Select this option to specify the expected longest round-trip time (in
milliseconds) of a message (for example, message and response). This
option allows expected traffic patterns to be input into the system so that
the timer calculations can be affected accordingly.
If this option is cleared, the default round-trip delay, which is two packet
cycles based on the average packet size, is used.
Minimal Offline
Time If a network message fails, a data point and its device are marked offline.
You can select Use Minimal Offline Time so that all the data points on
the offline device with pending network messages (read/write requests,
polls, or heartbeats) are marked offline and network messages are not sent
to them. This ensures that network performance is not impacted by an
offline device. This check box is cleared by default.
You can also set the minimum period of time (in seconds) that the
SmartServer waits before transmitting network messages to offline data
points. During this period, an offline device transmits an OFFLINE status
in response to data point requests. Once the Minimal Offline Time
elapses, the SmartServer sends a read/write request to one offline data
point. If the read/write request succeeds, the data point and its device are
marked online, and all cached read/write requests for the offline data
points on the device are executed.
The default Use Minimal Offline Time for a L ON W ORKS channel is 60
seconds.