National Instruments NI 4050 D

Glossary

CompactPCI refers to the core specification defined by the PCI Industrial Computer

Manufacturer’s Group (PICMG)

conversion device device that transforms a signal from one form to another. For example,

analog-to-digital converters (ADCs) for analog input, digital-to-analog

converters (DACs) for analog output, digital input or output ports, and

counter/timers are conversion devices.

conversion time the time required, in an analog input or output system, from the moment a

channel is interrogated (such as with a read instruction) to the moment that

accurate data is available

coupling the manner in which a signal is connected from one location to another

CPU central processing unit

crest factor the ratio of the peak value of the signal to the RMS value of the signal

CSM current shunt module

DAQ data acquisition—(1) collecting and measuring electrical signals from

sensors, transducers, and test probes or fixtures and inputting them to a

computer for processing; (2) collecting and measuring the same kinds of

electrical signals with A/D and/or DIO boards plugged into a computer, and

possibly generating control signals with D/A and/or DIO boards in the

same computer

dB decibel—the unit for expressing a logarithmic measure of the ratio of two

signal levels: dB=20log10 V1/V2, for signals in volts

DC direct current

default setting a 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.

device a plug-in data acquisition board, card, or pad that can contain multiple

channels and conversion devices. Plug-in boards, PCMCIA cards,

devices such as the DAQPad-1200, which connects to your computer

parallel port, are all examples of DAQ devices.