Campbell Scientific NL240 Wireless Network Link Interface - Manual (Page 27)

NL240 Wireless Network Link Interface
• If you have chosen WEP Security, enter the WEP key to be used for the
network in the Password field. (See Appendix C for details on the WEP
key requirements.)
• Select the Channel to be used for the network. (The Suggest Channel
button can be used to have the NL240 scan the networks for the channel
that is least likely to encounter interference from other networks.)
• Select the TX Power Level, Low Power Mode, Low Power Interval,
and Low Power On Time. (Note that these settings can often be left at
their default settings. See Section 6.5, Power.)
• Click Apply to save your changes.
8.2 Operational Mode
8.2.1 PakBus® Router
When the RS-232 or CS I/O port is configured as a PakBus® router, the
NL240 can route packets to other devices in the network that it has in its
routing table. These are devices that the NL240 has learned about through
beaconing or allowed-neighbor lists.
Beacon Interval – Devices in a PakBus® network may broadcast a hello-
message to other devices in order to determine “neighbor” devices. Neighbor
devices are devices that can be communicated with directly by the current
device without being routed through an intermediate device. A beacon in a
PakBus network helps to ensure that all devices in the network are aware of
which other devices are viable in the network. The beacon interval determines
how often a beacon will be sent out. Set the beacon interval to 0 to disable
beacons.
Verify Interval – This interval, in seconds, determines the rate at which the
NL240 will attempt to start a hello transaction with a neighbor if no other
communication has taken place within the interval. If Verify Interval is set to
0, the verify interval becomes 2.5 times the Beacon Interval. If both the
Beacon Interval and Verify Interval are set to 0, the verify interval becomes
300 seconds. Generally, the Verify Interval should be set greater than or equal
to the interval at which you will be talking to the attached PakBus devices. For
example, if you are using the NL240 as a PakBus router to allow scheduled
collection of a network of dataloggers every 15 minutes, consider setting the
Verify Interval to 30 minutes.
PakBus Neighbors Allowed – You can set a list of “acceptable neighbors”
which the NL240 expects to hear from within set intervals (the Verify
Interval). If the NL240 does not hear from neighbors in this list within the
Verify Interval, it will attempt to contact them on its own. It will ignore all
devices it hears that are not on the PakBus Neighbors Allowed list except if the
PakBus® address is ≥4000. Hellos from devices with PakBus address ≥4000
are automatically accepted as neighbors.
8.2.1.1 Physical Setup
Using the supplied serial cable, connect the NL240 CS I/O port or RS-232 port
to the datalogger CS I/O or RS-232 port, respectively. The NL240 will be
powered if connected via CS I/O. Alternatively, power the NL240 through the
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