Campbell Scientific CR9000X Measurement and Control System - Manual (Page 428)

Appendix E. Glossary
RMS root mean square or quadratic mean. A measure of the magnitude of
wave or other varying quantities around zero.
RS-232 Recommended Standard 232. A loose standard defining how two
computing devices can communicate with each other. The
implementation of RS-232 in CSI dataloggers to PC communications is
quite rigid, but transparent to most users. Implementation of RS-232 in
CSI datalogger to RS-232 smart sensor communications is quite flexible.
sample rate The rate at which measurements are made. Inverse of the Scan
Interval. The measurement sample rate is primarily of interest when
considering the effect of time skew (i.e., how close in time are a series of
measurements). The maximum sample rates are the rates at which
measurements are made when initiated by a single instruction with
multiple repetitions.
scan (execution interval)Error! Bookmark not defined. is the time interval
between initiating each execution of a given Scan interval. If the
Execution Interval is evenly divisible into 24 hours (86,400 seconds), the
Execution Interval is synchronized with 24 hour time, so that the scan is
executed at midnight and every execution interval thereafter. The table is
executed for the first time at the first occurrence of the Execution Interval
after compilation. If the Execution Interval does not divide evenly into 24
hours, execution will start on the first even second after compilation.
scan (frequency is the frequency of the Scan. This is equal to the reciprocal
of the Scan execution interval or Scan rate (1/(Scan Rate)) and usually has
units of Hertz (scans per second).
SDI-12 Serial/Digital Data Interface at 1200 bps. Communication protocol for
transferring data between data recorders and sensors.
SDM Synchronous Device for Measurement. A processor based peripheral
device or sensor that communicates with the CR1000 via hardwire over
short distance using a proprietary CSI protocol.
Seebeck Effect induces microvolt level thermal electromotive forces (EMF)
across junctions of dissimilar metals in the presence of temperature
gradients. This is the principle behind thermocouple temperature
measurement. It also causes small correctable voltage offsets in CR1000
measurement circuitry.
Send denotes the program send button in LoggerNetTM / PC400 / RTDAQ /
PC200W datalogger support software.
serial a loose term denoting output or a device that outputs an electronic series
of alphanumeric characters.
SI Système Internationale The International System of Units.
signature a number which is a function of the data and the sequence of data in
memory. It is derived using an algorithm which assures a 99.998%
probability that if either the data or its sequence changes, the signature
changes.
E-8