National Instruments USB-621 Series User Manual page 185

Glossary
G
glitch
GND
ground
H
hardware triggering
Hz
I
I/O
impedance
in.
instrument driver
NI USB-621x User Manual
An unwanted signal excursion of short duration that is usually unavoidable.
See ground.
1. A pin.
2. An electrically neutral wire that has the same potential as the
surrounding earth. Normally, a noncurrent-carrying circuit intended for
safety.
3. A common reference point for an electrical system.
A form of triggering where you set the start time of an acquisition and
gather data at a known position in time relative to a trigger signal.
1. Hertz—The SI unit for measurement of frequency. One hertz (Hz)
equals one cycle per second.
2. The number of scans read or updates written per second.
Input/Output—The transfer of data to/from a computer system involving
communications channels, operator interface devices, and/or data
acquisition and control interfaces.
1. The electrical characteristic of a circuit expressed in ohms and/or
capacitance/inductance.
2. Resistance.
Inch or inches.
A set of high-level software functions that controls a specific GPIB, VXI,
or RS232 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.
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