Campbell Scientific CR1000KD CR800 and CR850 Measurement and Control Systems - Page 33

Section 4. Quickstart Tutorial This tutorial presents an introduction to CR800 data acquisition. 4.1 Primer - CR800 Data-Acquisition Data acquisition with the CR800 is the result of a step-wise procedure involving the use of electronic sensor technology, the CR800, a telecommunications link, and datalogger support software (p. 76). 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 CR800 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. 449). 4.1.1.2 Datalogger 4.1.1.3 Data Retrieval The CR800 can measure almost any sensor with an electrical response. The CR800 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 CR800 will store data in memory awaiting transfer to the PC via external storage devices or telecommunications. 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 CR800 to the PC. Multiple users may have access to the same CR800 without compromising data or coordinating data collection activities. RS-232 and CS I/O ports are integrated with the CR800 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 33