Glossary
©
National Instruments Corporation
G-9
PCI-4451/4452/4453/4454 User Manual
INL
integral nonlinearity—a measure in LSB of the worst-case deviation from
the ideal A/D or D/A transfer characteristic of the analog I/O circuitry
input impedance
the measured resistance and capacitance between the input terminals of a
circuit
instrument driver
a set of high-level software functions that controls a specific GPIB, VXI,
or RS-232 programmable instrument or a specific plug-in DAQ device.
Instrument drivers are available in several forms, ranging from a function
callable language to a virtual instrument (VI) in LabVIEW.
instrumentation
amplifier
a circuit whose output voltage with respect to ground is proportional to the
difference between the voltages at its two inputs
interrupt
a computer signal indicating that the CPU should suspend its current task
to service a designated activity
I/O
input/output—the transfer of data to/from a computer system involving
communications channels, operator interface devices, and/or data
acquisition and control interfaces
I
OH
current, output high
I
OL
current, output low
IRQ
interrupt request
isolation
a type of signal conditioning in which you isolate the transducer signals
from the computer for safety purposes. This protects you and your
computer from large voltage spikes and makes sure the measurements from
the DAQ device are not affected by differences in ground potentials.
K
k
kilo—the standard metric prefix for 1,000, or 10
3
, used with units of
measure such as volts, hertz, and meters
kS
1,000 samples
