Campbell Scientific CR1000 Measurement and Control System - Manual (Page 33)

33
Section 4. Quickstart Tutorial
This tutorial presents an introduction to CR1000 data acquisition.
4.1 Primer – CR1000 Data-Acquisition
Data acquisition with the CR1000 is the result of a step-wise procedure involving
the use of electronic sensor technology, the CR1000, a telecommunications link,
and datalogger support software
(p. 77).
4.1.1 Components of a Data-Acquisition System
A typical data-acquisition system is conceptualized in figure Data-Acquisition
System Components
(p. 34).
A CR1000 is only one part of a data-acquisition system.
To acquire good data, suitable sensors and a reliable data-retrieval method are
required. A failure in any part of the system can lead to "bad" data or no data.
4.1.1.1 Sensors
Suitable sensors accurately and precisely transduce environmental change into
measurable electrical properties by outputting a voltage, changing resistance,
outputting pulses, or changing states.
Read More! See the appendix Accuracy, Precision, and Resolution
(p. 471).
4.1.1.2 Datalogger
The CR1000 can measure almost any sensor with an electrical response. The
CR1000 measures electrical signals and convert the measurement to engineering
units, perform calculations and reduce data to statistical values. Every
measurement does not need to be stored. The CR1000 will store data in memory
awaiting transfer to the PC via external storage devices or telecommunications.
4.1.1.3 Data Retrieval
The products of interest from a data acquisition system are data in data files,
usually stored on and accessible by a PC.
Data are copied, not moved, from the CR1000 to the PC. Multiple users may
have access to the same CR1000 without compromising data or coordinating data
collection activities.
RS-232 and CS I/O ports are integrated with the CR1000 wiring panel to
facilitate data collection.
On-site serial communications are preferred if the datalogger is near the PC, and
the PC can dedicate a serial (COM) port for the datalogger. On-site methods such
as direct serial connection or infrared link are also used when the user visits a
remote site with a laptop or PDA.
In contrast, telecommunications provide remote access and the ability to discover
problems early with minimum data loss. A variety of devices such as telephone