Glossary
G-6
ni.com
N
NC
not connected
noise
An undesirable electrical signal. Noise comes from external sources such
as the AC power line, motors, generators, transformers, fluorescent lights,
soldering irons, CRT displays, computers, electrical storms, welders, radio
transmitters, and internal sources such as semiconductors, resistors, and
capacitors. Noise corrupts signals you are trying to send or receive.
non-inverting
The polarity of a switch (limit switch, home switch, etc.) in
active
state. If
these switches are active high, they are said to have non-inverting polarity.
See also
NPN sensor
A sensor type with a sinking only output stage.
O
open-loop
Refers to a motion control system where no external sensors (feedback
devices) are used to provide position or velocity correction signals.
P
PCI
peripheral component interconnect—a high-performance expansion bus
architecture originally developed by Intel to replace ISA and EISA. It is
achieving widespread acceptance as a standard for PCs and workstations;
it offers a theoretical maximum transfer rate of 132 MB/s.
PNP sensor
A sensor type with a sourcing only output stage.
port
(1) A communications connection on a computer or a remote controller.
(2) A digital port, consisting of eight lines of digital input and/or output.
position breakpoint
Position breakpoint for an encoder can be set in absolute or relative
quadrature counts. When the encoder reaches a position breakpoint, the
associated breakpoint output immediately transitions.
