Specifications

14-1
Section 14. PakBus Overview
Read more! This section is provided as a primer to PakBus
communications. Complete information is available in Campbell
Scientific’s “PakBus Networking Guide.”
The CR1000 communicates with computers or other dataloggers via PakBus.
PakBus is a proprietary telecommunications protocol similar in concept to IP
(Internet protocol). PakBus allows compatible Campbell Scientific dataloggers
and telecommunications hardware to seamlessly link to a PakBus network.
14.1 PakBus Addresses
CR1000s 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 Fig.
1, is to assign single-digit addresses to the first tier of nodes, multiples of tens
to the second tier, multiples of 100s 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, CR1000 status
table, or with a CR1000KD 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 PakBus
Graph 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.
14.2 Nodes: Leaf Nodes and Routers
• A PakBus network consists of 2 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.