National Instruments DAQ M Series User Manual
Page 148
Glossary
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power source
An instrument that provides one or more sources of AC or DC power. Also
known as power supply.
ppm
Parts per million.
pretriggering
The technique used on a DAQ device to keep a continuous buffer filled with
data, so that when the trigger conditions are met, the sample includes the
data leading up to the trigger condition.
pulse
A signal whose amplitude deviates from zero for a short period of time.
pulse width
The time from the rising to the falling slope of a pulse (at 50% amplitude).
PXI
A rugged, open system for modular instrumentation based on CompactPCI,
with special mechanical, electrical, and software features. The PXIbus
standard was originally developed by National Instruments in 1997, and is
now managed by the PXIbus Systems Alliance.
PXI Express
PCI Express eXtensions for Instrumentation—The PXI implementation of
PCI Express, a scalable full-simplex serial bus standard that operates at
2.5 Gbps and offers both asynchronous and isochronous data transfers.
PXI_STAR
A special set of trigger lines in the PXI backplane for high-accuracy device
synchronization with minimal latencies on each PXI slot. Only devices in
the PXI Star controller Slot 2 can set signal on this line. For additional
information concerning PXI star signal specifications and capabilities,
refer to the PXI Specification located at
www.pxisa.org/specs
.
Q
quadrature encoder
An encoding technique for a rotating device where two tracks of
information are placed on the device, with the signals on the tracks offset
by 90° from each other. This makes it possible to detect the direction of the
motion.
R
range
The maximum and minimum parameters between which a sensor,
instrument, or device operates with a specified set of characteristics. This
may be a voltage range or a frequency range.