
Glossary
DAQ Hardware Overview Guide G-10 www.ni.com
remote SCXI An SCXI configuration in which a serial port cable is connected to
an SCXI-2000 chassis or an SCXI-100X chassis with an SCXI-2400
remote communications module. Multiple remote SCXI units can be
connected to one serial port in a PC by using RS-485. You can use either an
RS-485 interface card in your PC or an RS-485 converter on the RS-232
port.
REQ request signal
resolution The smallest signal increment that can be detected by a measurement
system. Resolution can be expressed in bits, in proportions, or in percent of
full scale. For example, a system has 12-bit resolution, one part in 4,096
resolution, and 0.0244 percent of full scale.
ROM read-only memory
RMS root mean squared
RTD Resistance temperature detector. A metallic probe that measures
temperature based upon its coefficient of resistivity.
RTSI Real-Time System Integration (bus). The National Instruments timing bus
that connects DAQ devices directly, for precise synchronization of
functions.
RVDT Rotary Variable Differential Transformer. Transformer-based sensor for
measuring absolute angular displacement. Measurement range is typically
between +/- and +/- degrees.
S
s seconds
S samples
Sample-and-Hold
(S/H)
A circuit that acquires and stores an analog voltage on a capacitor for a
short period of time.
sample counter A counter used to tally the number of A/D conversions (samples),
generated either by the onboard sample-interval counter or externally, and
shuts down the data acquisition timing circuitry when the number of
samples you want have been acquired.
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