15.4 DNP3 communications
DNP3 is designed to optimize transmission of data and control commands from a master
computer to one or more remote devices or outstations. The data logger allows DNP3
communications on all available communications ports. CRBasic DNP3 instructions include:
l
DNP()
l
DNPUpdate()
l
DNPVariable()
See the CRBasic Editor help for detailed instruction information and program examples:
https://help.campbellsci.com/crbasic/cr300/.
When
DNPUpdate()
is used to set up the data logger as a remote (slave) device, up to three
DNP3 masters are supported.
For additional information on DNP3 see:
l
DNP3 with Campbell Scientific Dataloggers
l
l
How to Access Your Measurement Data Using DNP3
15.5 PakBus communications
PakBus is a Campbell Scientific communications protocol. By using signed data packets, PakBus
increases the number of communication and networking options available to the data logger.
The data logger allows PakBus communications on all available communications ports. For
additional information, see
The Many Possibilities of PakBus Networking
blog article.
Advantages of PakBus include:
l
Simultaneous communications between the data logger and other devices.
l
Peer-to-peer communications - no computer required. Special CRBasic instructions simplify
transferring data between data loggers for distributed decision making or control.
l
Data consolidation - other PakBus data loggers can be used as "sensors" to consolidate all
data into one data logger.
l
Routing - the data logger can act as a router, passing on messages intended for another
Campbell Scientific data logger. PakBus supports automatic route detection and selection.
l
Short distance networks - a data logger can talk to another data logger over distances up
to 30 feet by connecting transmit, receive, and ground wires between the data loggers.
In a PakBus network, each data logger is assigned a unique address. The default PakBus address
in most devices is 1. To communicate with the data logger, the data logger support software must
15. Communications protocols
97