Campbell CR850, Руководство оператора

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Section 8. Operation
335
8.5.1 PakBus Addresses
CR800s are assigned PakBus ® address 1 as a factory default. Networks with more
than a few stations should be organized with an addressing scheme that
guarantees unique addresses for all nodes. One approach, demonstrated in figure
PakBus Network Addressing
(p. 336)
, is to assign single-digit addresses to the first
tier of nodes, double-digit to the second tier, triple-digit to the third, etc. Note that
each node on a branch starts with the same digit. Devices, such as PCs, with
addresses greater than 4000 are given special administrative access to the network
PakBus addresses are set using DevConfig , PakBusGraph , CR800 Status table, or
with an external keyboard / display. DevConfig ( Device Configuration Utility ) is
the primary settings editor for Campbell Scientific equipment. It requires a
hardwire RS-232 connection to a PC and allows backup of settings on the PC hard
drive.
PakBusGraph is used over a telecommunications link to change settings,
but has no provision for backup.
Caution Care should be taken when changing PakBus
®
addresses with
PakBusGraph or in the Status table. If an address is changed to an unknown
value, a field visit with a laptop and DevConfig may be required to discover the
unknown address.
8.5.2 Nodes: Leaf Nodes and Routers
•
A PakBus ® network consists of two to 4093 linked nodes.
•
One or more leaf nodes and routers can exist in a network.
•
Leaf nodes are measurement devices at the end of a branch of the PakBus
®
web.
o Leaf nodes can be linked to any router.
o
A leaf node cannot route packets but can originate or receive them.
•
Routers are measurement or telecommunications devices that route packets to
other linked routers or leaf nodes.
o
Routers can be branch routers. Branch routers only know as neighbors
central routers, routers in route to central routers, and routers one level
outward in the network.
o
Routers can be central routers. Central routers know the entire network.
A PC running
LoggerNet is typically a central router.
o
Routers can be router-capable dataloggers or communications devices.
The CR800 is a leaf node by factory default. It can be configured as a router by
setting
IsRouter in its Status table to 1 or True . The network shown in figure
PakBus Network Addressing
(p. 336)
contains six routers and eight leaf nodes.
8.5.2.1 Router and Leaf-Node Configuration
Consult the appendix Router and Leaf-Node Hardware for a table of available
PakBus® leaf-node and router devices.