Campbell CRVW3, Instruction Manual

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CRVW3 3-Channel Vibrating-Wire Datalogger
66
10.2.3 Repeater Planning
A repeater station can be implemented using a CRVW3 station or it can be a
dedicated repeater station (repeater-only station). If it makes sense to measure
one or more vibrating-wire sensors near the proposed repeater site, deploy a
CRVW3 repeater, otherwise plan for a dedicated repeater station.
Design your network with repeater stations in strategic locations to overcome
line-of-sight problems or signal strength difficulties in the network. A CRVW3
end-node station may be too far away from the base station to communicate
properly, or blocked from the base station by interfering geographic features.
In those cases, the CRVW3 end-node should route its radio communications
through a repeater station to reach the base station. In a few cases, multiple
repeaters may be needed to establish a route from a CRVW3 end-node to the
base station.
You should make a field visit to validate your planned repeater site locations
(see Section 10.2.8.1 , Pre-procurement Field Visits
(p. 71)
).
Each conveyance of data from one station to another is called a “radio hop” or
simply a “hop”. A CRVW3 end-node that communicates directly with the base
station is said to have a “single-hop” link. When a CRVW3 end-node
communicates with the base station via one repeater station it is said to have a
“dual-hop” or “2-hop” link. When an end-node routes through two or more
repeaters, it is referred to as a “multi-hop” link.
A repeater station is always required to communicate with multiple remote
stations, therefore an omnidirectional antenna should be used on the station
(often called an “omni” antenna).
You should designate on the map of your network plan which CRVW3 devices
will act as repeater stations. You should also identify the locations of any
dedicated repeater stations.
For specific information relating to CRVW3-RF451 repeaters and RF451-
based dedicated repeaters, see Section 10.2.6 , Planning RF451 Radio Networks
(p. 68)
. For specific information relating to CRVW3-RF407 repeaters and
RF407-based dedicated repeaters, see Section 10.2.7 ,
Planning RF407 Radio
Networks
(p. 69)
.
10.2.4 LoggerNet Station Planning
When planning your network, you need to finalize the location of the computer
that will permanently run the LoggerNet software and which will operate as the
first-stage permanent data repository (see Section 10.1.1 , LoggerNet Computer
Station
(p. 58)
). One of the key factors to consider when making this decision is
how the base station will communicate with the LoggerNet computer.
If you choose to deploy the LoggerNet computer in the field, within radio range
of some or all of the CRVW3 stations, the LoggerNet computer will be co-
located with the radio base station. In that case, only a serial cable is needed to
connect between the computer and the base station’s radio device. LoggerNet
controls the base radio via the serial cable to make connections with all
CRVW3 devices. Consider that a protective location must be procured for the
LoggerNet
computer, power provided, and that some sort of network
connectivity between LoggerNet and your office location must be established.