Campbell CR1000 User Manual

Section 7. Installation
Term. MSB
Most significant bit (the leading bit). See the appendix Endianness
(p. 643).
Term. RS-232C
Refers to the standard used to define the hardware signals and voltage levels.
The CR1000 supports several options of serial logic and voltage levels
including RS-232 logic at TTL levels and TTL logic at TTL levels.
Term. RX
Receive
Term. SP
Space
Term. start bit
Is the bit used to indicate the beginning of data.
Term. stop bit
Is the end of the data bits. The stop bit can be 1, 1.5 or 2.
Term. TX
Transmit
7.9.17.5 Serial I/O CRBasic Programming
To transmit or receive RS-232 or TTL signals, a serial port (see table CR1000
Serial Ports
(p. 247)) must be opened and configured through CRBasic with the
SerialOpen() instruction. The SerialClose() instruction can be used to close the
serial port. Below is practical advice regarding the use of SerialOpen() and
SerialClose(). Program CRBasic example Receiving an RS-232 String
(p. 254)
shows the use of SerialOpen(). Consult CRBasic Editor Help for more
information.
SerialOpen(COMPort,BaudRate,Format,TXDelay,BufferSize)
• COMPort — Refer to CRBasic Editor Help for a complete list of COM ports
available for use by SerialOpen().
• BaudRate — Baud rate mismatch is frequently a problem when developing a
new application. Check for matching baud rates. Some developers prefer to
use a fixed baud rate during initial development. When set to -nnnn (where
nnnn is the baud rate) or 0, auto baud-rate detect is enabled. Autobaud is
useful when using the CS I/O and RS-232 ports since it allows ports to be
simultaneously used for sensor and PC telecommunications.
• Format — Determines data type and if PakBus
®
communications can occur
on the COM port. If the port is expected to read sensor data and support
normal PakBus
®
telemetry operations, use an auto-baud rate argument (0 or -
nnnn) and ensure this option supports PakBus
®
in the specific application.
• BufferSize — The buffer holds received data until it is removed. SerialIn(),
SerialInRecord(), and SerialInBlock() instructions are used to read data
249

Campbell CR1000 Specifications

General

Power Requirements	9.6 to 16 VDC
Data Logger Operating System	CRBasic
Memory	4 MB
Analog Inputs	16 single-ended or 8 differential
Analog Input Resolution	13 bits
Analog Input Range	+/-2.5V
Digital I/O	8
Pulse Counters	2
Communication Ports	RS-232
Operating Temperature	-25°C to +50°C
Pulse Channels	4