National Instruments DAQ M Series User Manual
Page 139
Glossary
© National Instruments Corporation
G-5
counter
1. Software. A memory location used to store a count of certain
occurrences.
2. Hardware. A circuit that counts events. When it refers to an instrument,
it refers to a frequency counter.
counter/timer
A circuit that counts external pulses or clock pulses (timing).
D
D GND
Digital ground signal.
D-SUB connector
A serial connector.
DAC
Digital-to-Analog Converter—An electronic device, often an integrated
circuit, that converts a digital number into a corresponding analog voltage
or current.
In the instrumentation world, DACs can be used to generate arbitrary
waveform shapes, defined by the software algorithm that computes the
digital data pattern, which is fed to the DAC.
DAQ
1. Data acquisition—The process of collecting and measuring electrical
signals from sensors, transducers, and test probes or fixtures and
inputting them to a computer for processing.
2. Data acquisition—The process of collecting and measuring the same
kinds of electrical signals with A/D and/or DIO devices plugged into a
computer, and possibly generating control signals with D/A and/or
DIO devices in the same computer.
DAQ device
A device that acquires or generates data and can contain multiple channels
and conversion devices. DAQ devices include plug-in devices, PCMCIA
cards, and DAQPad devices, which connect to a computer USB or 1394
(FireWire
®
) port. SCXI modules are considered DAQ devices.
DAQ-STC2
Data acquisition system timing controller chip.
data acquisition
The general concept of acquiring data, as in begin data acquisition or data
acquisition and control. See also DAQ.