Campbell SR50AT, Инструкция по эксплуатации

Страница: 23 / 84

SR50AT-Series Sonic Ranging Sensors
11
7.3 SDI-12 Programming
Short Cut is the best source for up-to-date datalogger programming code.
Programming code is needed when:
• Creating a program for a new datalogger installation
•
Adding sensors to an existing datalogger program
If your data acquisition requirements are simple, you can probably create and
maintain a datalogger program exclusively with
Short Cut
. If your data
acquisition needs are more complex, the files that Short Cut creates are a great
source for programming code to start a new program or add to an existing
custom program.
Short Cut cannot edit programs after they are imported and edited
in CRBasic Editor .
A Short Cut tutorial is available in Section 4 , QuickStart
(p. 2)
. If you wish to
import Short Cut code into CRBasic Editor to create or add to a customized
program, follow the procedure in Appendix A , Importing Short Cut Code Into
CRBasic Editor
(p. A-1)
. Programming basics for CRBasic dataloggers are in the
following section. Complete program examples for select CRBasic dataloggers
can be found in Appendix B ,
Example Programs
(p. B-1)
.
7.3.1 SDI12Recorder() Instruction
The SDI12Recorder() measurement instruction programs CRBasic
dataloggers (CR200(X) series, CR300 series, CR6 series, CR800-series,
CR1000, CR3000, and CR5000) to measure the sensor. This instruction sends a
request to the sensor to make a measurement and then retrieves the
measurement from the sensor. See Section 8.3 ,
SDI-12 Measurements
(p. 14)
, for
more information.
When using a CR200(X), the SDI12Recorder() instruction has the following
syntax:
SDI12Recorder (Destination,OutString,Multiplier,Offset)
For the other CRBasic dataloggers, the
SDI12Recorder()
instruction has the
following syntax:
SDI12Recorder (Destination, SDIPort, SDIAddress, “SDICommand”,
Multiplier, Offset, FillNAN (optional), WaitonTimeout
(optional))
8. Operation
The SR50AT performs multiple echo processing regardless of output formats.
It bases every measurement on several readings and applies an algorithm to
improve measurement reliability.
The distance to target readings that are obtained from the sensor are referenced
from the metal mesh on the face of the transducer. The SR50AT projects an
ultrasonic beam that can pick up objects in its field of view that is 30° or less.
The closest object to the sensor will be detected if it is within this field of view.
Unwanted objects must be outside the field of view. If a target is in motion, the
NOTE