CR300-Series Datalogger
35
• Modbus
• DNP3
• Campbell Scientific PakBus networks
6.5.1.1 USB Port
One micro-B USB port, labeled USB, for communicating with a PC through
datalogger support software. Powering through the USB port has the limitations
discussed in Section 6.7.1.1, Power Sources
(p. 39).
6.5.1.2 RS-232 Port
One nine-pin DCE port, labeled RS-232, normally used to communicate with a
PC running datalogger support software, to connect a modem read a smart
sensor (see Section 6.5.2, General Serial Communications
(p. 35)). With a null
modem adapter attached, it serves as a DTE device.
6.5.1.3 SDI-12 Ports
SDI-12 is a 1200-baud protocol that supports many smart sensors (see Section
6.5.3, SDI-12 Communications
(p. 35)). C1 and C2 can each be configured as an
SDI-12 communication port.
6.5.2 General Serial Communications
The CR300 supports two-way serial communication through two ports
configurable for RS-232 input. In addition to the nine-pin RS-232 port,
terminals C1 and C2 can be configured as a pair to create an RS-232
communication port, called Com1. Ports can be formatted as described in
CRBasic Editor Help.
These two ports can be used with smart sensors that deliver measurement data
through serial data protocols or with devices such as modems that
communicate using serial data protocols.
CRBasic instructions for general serial communications include:
• SerialOpen()
• SerialClose()
• SerialIn()
• SerialInRecord()
• SerialInBlock()
• SerialOut()
• SerialOutBlock()
To communicate over a serial port, it is important to be familiar with the
protocol of the sensor or device. Refer to the manual of the sensor or device to
find its protocol and then select the appropriate options for each CRBasic
parameter. See the application note Interfacing Serial Sensors with Campbell
Scientific Dataloggers, available at www.campbellsci.com, for more
programming details and examples.
6.5.3 SDI-12 Communications
SDI-12 is a smart-sensor protocol that uses one terminal configured for SDI-
12. Terminals C1 and C2 can each be configured as an SDI-12 communication
terminal.
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