Glossary

NI ELVISmx Help

Edition Date: June 2015

Part Number: 372500F-01

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Prefixes

Symbol Prefix Value
p pico 10 -12
n nano 10 -9
µ micro 10 -6
m milli 10 -3
k kilo 10 3
M mega 10 6
G giga 10 9
T tera 10 12

Numbers/Symbols

nV nanovolts 10-9 volts
µV microvolts 10-6 volts
µΩ microohms 10-6 ohms
mΩ milliohms 10-3 ohms
MΩ megaohms 106 ohms
pA picoamps 10-12 amperes
nA nanoamps 10-9 amperes
µA microamps 10-6 amperes
mA milliamps 10-3 amperes

A

Aamperes
ACalternating current
AIanalog input
aliasA false lower frequency component that appears in sampled data acquired at too low a sampling rate.
AMAmplitude Modulation—The process in which the amplitude of a carrier wave is varied to be directly proportional to the amplitude of the modulating signal.
amplificationA type of signal conditioning that makes the signal larger to use more of the available range.
amplitudeThe voltage amplitude of a signal. When speaking of the amplitude of a signal, it is usually assumed to be the RMS value for an AC signal. However, amplitude can also refer to the instantaneous amplitude, or the peak, peak-to-peak, or average amplitude, if so specified.
AOanalog output
APIApplication Programming Interface. A standardized set of subroutines or functions along with the parameters that a program can call.
ARBArbitrary waveform generator

B

BJTBipolar junction transistor—A three-terminal electronic valve. There are two types of BJT: PNP and NPN.
block diagramPictorial description or representation of a program or algorithm in LabVIEW. The block diagram, consists of executable icons called nodes and wires that carry data between the nodes. The block diagram is the source code for the VI. The block diagram resides in the block diagram window of the VI.
BNCA type of coaxial signal connector.
Bode plotThe plot of the gain and phase of a system as a function of frequency.

C

CCelsius
capacitanceThe ability to hold an electrical charge.
CHchannel
channelPin or wire lead to which you apply or from which you read the analog or digital signal. Analog signals can be single-ended or differential. For digital signals, you group channels to form ports. Ports usually consist of either four or eight digital channels.
coaxialWire type that consists of a center wire enclosed in insulation and then a grounded shield of braided wire. The shield minimizes electrical and radio frequency interference.
counter/timerA circuit that counts external pulses or clock pulses (timing).

D

D/Adigital-to-analog
DACdigital-to-analog converter
DAQdata acquisition
dBdecibel—The unit for expressing a logarithmic measure of the ratio of two signal levels: dB = 20log10 V1/V2, for signals in volts.
dBmUsed in reference frequency (RF) measurements, 0 dBm is defined as 1 mW of RF signal dissipated in a 50 W resistive load.
DCdirect current
default settingA default parameter value recorded in the driver. In many cases, the default input of a control is a certain value (often 0) that means use the current default setting.
deviceA plug-in data acquisition product, card, or pad that can contain multiple channels and conversion devices. Plug-in products, PCMCIA cards, and devices such as the E Series DAQPads, which connect to your computer parallel port, are all examples of DAQ devices.
differential inputAn analog input consisting of two terminals, both of which are isolated from computer ground, whose difference is measured.
digital triggerA TTL level signal having two discrete levels—a high and a low level.
DIOdigital I/O
diodeA specialized electronic component with two electrodes called the anode and the cathode.
DMMdigital multimeter
DO <0..7>Digital output signals from the NI ELVIS DO bus.
DSAdynamic signal analyzer

E

EEPROMElectrically Erasable Programmable Read-Only Memory—ROM that can be erased with an electrical signal and reprogrammed.
ELVISEducational Laboratory Virtual Instrumentation Suite
Express VIA subVI designed to aid in common measurement tasks. You configure an Express VI using a configuration dialog box.

F

FGEN
  1. Abbreviation for the NI ELVISmx Function Generator software instrument.
  2. Output signal for the NI ELVIS II Series function generator.
floating signal sourcesSignal sources with voltage signals that are not connected to an absolute reference or system ground. Also called nonreferenced signal sources. Some common example of floating signal sources are batteries, transformers, or thermocouples.
frequencyThe basic unit of rate, measured in events or oscillations per second using a frequency counter or spectrum analyzer. Frequency is the reciprocal of the period of a signal.
front panelThe user interface of a LabVIEW virtual instrument.

G

gainThe factor by which a signal is amplified, sometimes expressed in decibels.
grounded signal sourcesSee referenced signal sources.

H

hardware triggeringA 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.
HzHertz—The number of scans read or updates written per second.

I

I/Oinput/output—The transfer of data to/from a computer system involving communications channels, operator interface devices, and/or data acquisition and control interfaces.
in.inch or inches
inductanceThe characteristic of a coil that generates a voltage due to changes in the current. An inductor creates a voltage that is the derivative of the current, while a capacitor creates a voltage that is the integral of the current.
instrument driverA set of software routines that control a programmable instrument. Each routine corresponds to a programmatic operation such as configuring, reading from, writing to, and triggering the instrument. Instrument drivers simplify instrument control by eliminating the need to learn the programming protocol for the instrument.

L

LabVIEWA graphical programming language.
LEDlight-emitting diode

N

NI-DAQmxNational Instruments driver software for data acquisition (DAQ) hardware.
NPN transistorA two-junction (bipolar) semiconductor transistor with an N-type collector and emitter and a P-type base. An NPN transistor is created by adding a thin layer of P-type semiconductor material between two regions of N-type material.

O

op-ampoperational amplifier—Pre-built amplifier modules that are general enough to be used almost anywhere an amplifier is needed.

P

PCBprinted circuit board
phase shiftThe shift of a periodic signal, often measured referenced to its zero crossing, compared to a reference signal of the same frequency.
PNP transistorA junction transistor having an n-type semiconductor between a p-type semiconductor that serves as an emitter, and a p-type semiconductor that serves as a collector.

R

referenced signal sourcesSignal sources with voltage signals that are referenced to a system ground, such as the earth or a building ground. Also called grounded signal sources.
resistanceThe resistance to the flow of electric current. One ohm (Ω) is the resistance through which one volt of electric force causes one ampere to flow.
rmsroot mean square

S

sseconds
Ssamples
S/ssamples per second—Used to express the rate at which a DAQ device samples an analog signal.
ScopeAbbreviation for the NI ELVISmx Oscilloscope software instrument.
SINADsignal in noise and distortion
subVIVI used on the block diagram of another VI. Comparable to a subroutine.

T

THDtotal harmonic distortion
TIOtiming I/O
TRIGTrigger signal.
triggerAny event that causes or starts some form of data capture.
TTLtransistor-to-transistor logic

V

Vvolts
VIvirtual instrument—A combination of hardware and/or software elements, typically used with a PC, that has the functionality of a classic stand-alone instrument.
VOLTAGEInput signals for the NI ELVIS - DMM voltmeter.
Vp-ppeak-to-peak voltage

W

waveformMultiple voltage readings taken at a specific sampling rate.

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