Glossary
©
National Instruments Corporation
G-5
DAQCard-DIO-24 User Manual
EPROM
erasable programmable read-only memory—ROM that can be erased
(usually by ultraviolet light exposure) and reprogrammed
F
FIFO
first-in first-out memory buffer—the first data stored is the first data
sent to the acceptor. FIFOs are often used on DAQ devices to
temporarily store incoming or outgoing data until that data can be
retrieved or output. For example, an analog input FIFO stores the results
of A/D conversions until the data can be retrieved into system memory,
a process that requires the servicing of interrupts and often the
programming of the DMA controller. This process can take several
milliseconds in some cases. During this time, data accumulates in the
FIFO for future retrieval. With a larger FIFO, longer latencies can be
tolerated. In the case of analog output, a FIFO permits faster update
rates, because the waveform data can be stored on the FIFO ahead of
time. This again reduces the effect of latencies associated with getting
the data from system memory to the DAQ device
filtering
a type of signal conditioning that allows you to filter unwanted signals
from the signal you are trying to measure
G
GND
ground signal
GPCTR
general-purpose counter
H
handshaked digital I/O
a type of digital acquisition/generation where a device or module
accepts or transfers data after a digital pulse has been received; also
called latched digital I/O
hardware
the physical components of a computer system, such as the circuit
boards, plug-in boards, chassis, enclosures, peripherals, cables, and so
on
hex
hexadecimal
Hz
hertz—the number of scans read or updates written per second
