Communications Protocols - Campbell CR300 Series Product Manual

15. Communications protocols

Data loggers communicate with data logger support software, other Campbell Scientific data
loggers, and other hardware and software using a number of protocols including PakBus,
Modbus, DNP3, and TCP/IP. Several industry-specific protocols are also supported. See also
Communications specifications
15.1 General serial communications
15.2 Modbus communications
15.3 Internet Communications
15.4 DNP3 communications
15.5 PakBus communications
15.6 SDI-12 communications
Some communications services, such as satellite networks, can be expensive to send and receive
information. Best practices for reducing expense include:
Public
Declare
l
declared as Dim.
Be conservative with use of string variables and string variable sizes. Make string variables
l
as big as they need to be and no more. The default size, if not specified, is 24 bytes, but the
minimum is 4 bytes. Declare string variables
tables only as needed.
GetVariables()
When using
l
loggers, put the data in an array and use one command to get the multiple values. Using
one command to get 10 values from an array and swath of 10 is more efficient (requires
only 1 transaction) than using 10 commands to get 10 single values (requires 10
transactions). See the CRBasic Editor help for detailed instruction information and program
examples: https://help.campbellsci.com/crbasic/cr300/.
(p. 193).
only those variables that need to be public. Other variables should be
SendVariables()
/
Public
and sample string variables into data
to send values between data
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15. Communications protocols 85