G-18
©
National Instruments Corporation
Glossary
rise time
the difference in time between the 10% and 90% points of a system’s step
response
R
L
load resistance
rms
root mean square
RTD
resistive temperature device
S
s
seconds
S
samples
sample counter
the clock that counts the output of the channel clock, in other words, the
number of samples taken. On boards with simultaneous sampling, this
counter counts the output of the scan clock and hence the number of scans.
SCADA
supervisory control and data acquisition—a common PC function in
process control applications, where programmable logic controllers (PLCs)
perform control functions but are monitored and supervised by a PC
scan
one or more analog or digital input samples. Typically, the number of input
samples in a scan is equal to the number of channels in the input group. For
example, one pulse from the scan clock produces one scan which acquires
one new sample from every analog input channel in the group.
SCANCLK
scan clock signal
scan clock
the clock controlling the time interval between scans. On boards with
interval scanning support (for example, the AT-MIO-16F-5), this clock
gates the channel clock on and off. On boards with simultaneous sampling
(for example, the EISA-A2000), this clock clocks the track-and-hold
circuitry.
scan rate
the number of scans per second. For example, a scan rate of 10 Hz means
sampling each channel 10 times per second.
SCXI
Signal Conditioning eXtensions for Instrumentation
SE
single-ended inputs
shared memory
See dual-access memory
