Campbell Scientific CR6 CR6 Measurement and Control System - Page 393

Data Retrieval and Telecommunications - Details, Protocols, Conserving Bandwidth

Page 393 highlights

Section 8. Operation memory from the card if the binary form of the compiled program does not exceed the available main memory (p. 373). 8.4 Data Retrieval and Telecommunications - Details Reading List: • Data Retrieval and Telecommunications - Quickstart (p. 39) • Data Retrieval and Telecommunications - Overview (p. 84) • Data Retrieval and Telecommunications - Details (p. 393) • Data Retrieval and Telecommunications Peripherals - Lists (p. 601) Telecommunications, in the context of CR6 operation, is the movement of information between the CR6 and another computing device, usually a PC. The information can be data, program, files, or control commands. Telecommunication systems require three principal components: hardware, carrier signal, and protocol. For example, a common way to communicate with the CR6 is with PC200W software by way of a PC COM port. In this example, hardware are the PC COM port, CR6 RS-232 port,or USB port, and a serial cable. The carrier signal is RS-232, and the protocol is PakBus®. Of these three, you will most often be required to choose only the hardware, since carrier signal and protocol are transparent in most applications. Systems usually require a single type of hardware and carrier signal. Some applications, however, require hybrid systems of two or more hardware and signal carriers. Contact a Campbell Scientific application engineer for assistance in configuring a telecommunication system. Synopses of software to support telecommunication devices and protocols are found in the appendix Support Software (p. 604). Of special note is Network Planner, a LoggerNet client designed to simplify the configuration of PakBus telecommunication networks. 8.4.1 Protocols The CR6 communicates with datalogger support software (p. 89) and other Campbell Scientific dataloggers (p. 595) using the PakBus (p. 503) protocol (PakBus Overview (p. 395) ). Modbus, DNP3, and web API are also supported. See Alternate Telecommunications and Data Retrieval - Overview (p. 409). CAN bus is also supported when using the Campbell Scientific SDM-CAN (p. 601) communication module. 8.4.2 Conserving Bandwidth Some telecommunication services, such as satellite networks, can be expensive to send and receive information. Best practices for reducing expense include: • Declare Public only those variables that need to be public. • Be conservative with use of string variables and string variable sizes. Make string variables as big as they need to be and no more; remember the minimum is actually 24 bytes. Declare string variables Public and sample string variables into data tables only as needed. 393

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Section 8.
Operation
memory from the card if the binary form of the compiled program does not
exceed the available
main memory
(p. 373).
8.4
Data Retrieval and Telecommunications — Details
Reading List:
Data Retrieval and Telecommunications — Quickstart
(p. 39)
Data Retrieval and Telecommunications — Overview
(p. 84)
Data Retrieval and Telecommunications — Details
(p. 393)
Data Retrieval and Telecommunications Peripherals — Lists
(p. 601)
Telecommunications, in the context of CR6 operation, is the movement of
information between the CR6 and another computing device, usually a PC.
The
information can be data, program, files, or control commands.
Telecommunication systems require three principal components: hardware, carrier
signal, and protocol.
For example, a common way to communicate with the CR6
is with
PC200W
software by way of a PC COM port.
In this example, hardware
are the PC COM port, CR6
RS-232
port,or
USB
port, and a serial cable.
The
carrier signal is RS-232, and the protocol is PakBus
®
.
Of these three, you will
most often be required to choose only the hardware, since carrier signal and
protocol are transparent in most applications.
Systems usually require a single type of hardware and carrier signal.
Some
applications, however, require hybrid systems of two or more hardware and signal
carriers.
Contact a Campbell Scientific application engineer for assistance in configuring a
telecommunication system.
Synopses of software to support telecommunication devices and protocols are
found in the appendix
Support Software
(p. 604).
Of special note is
Network
Planner
,
a
LoggerNet
client designed to simplify the configuration of PakBus
telecommunication networks.
8.4.1
Protocols
The CR6 communicates with
datalogger support software
(p. 89)
and other
Campbell Scientific
dataloggers
(p. 595)
using the
PakBus
(p. 503)
protocol (
PakBus
Overview
(p. 395)
).
Modbus, DNP3, and web API are also supported.
See
Alternate Telecommunications and Data Retrieval — Overview
(p. 409).
CAN bus
is also supported when using the Campbell Scientific
SDM-CAN
(p. 601)
communication module.
8.4.2
Conserving Bandwidth
Some telecommunication services, such as satellite networks, can be expensive to
send and receive information.
Best practices for reducing expense include:
Declare
Public
only those variables that need to be public.
Be conservative with use of string variables and string variable sizes.
Make
string variables as big as they need to be and no more; remember the
minimum is actually 24 bytes.
Declare string variables
Public
and sample
string variables into data tables only as needed.
393