Glossary
Measure Data Acquisition User Manual
G-4
© National Instruments Corporation
DMA
Direct memory access. A method by which data you can transfer
data to computer memory from a device or memory on the bus
(or from computer memory to a device) while the processor does
something else. DMA is the fastest method of transferring data
to or from computer memory.
driver
Software that controls a specific hardware device, such as a data
acquisition board.
E
EISA
Extended Industry Standard Architecture.
external trigger
A voltage pulse from an external source that triggers an event
such as A/D conversion.
F
FIFO
A first-in-first-out memory buffer. In a FIFO, the first data
stored is the first data sent to the acceptor.
G
gain
The factor by which a signal is amplified, sometimes expressed
in decibels.
I
input limits
The upper and lower voltage inputs for a channel. You must use
a pair of numbers to express the input limits. The VIs can infer
the input limits from the input range, input polarity, and input
gain(s). Similarly, if you wire the input limits, range, and
polarity, the VIs can infer the onboard gains when you do not
use SCXI.
input range
The difference between the maximum and minimum voltages an
analog input channel can measure at a gain of 1. The input range
is a scalar value, not a pair of numbers. By itself the input range
