Glossary
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National Instruments Corporation
G-3
NI 951x User Manual
high-side switch
A switch that provides a path to supply when closed.
home switch (input)
A physical position determined by the mechanical system or designer as the
reference location for system initialization. Frequently, the home position is
also regarded as the zero position in an absolute position frame of reference.
I
incremental encoder
A device that produces two signals, Phase A and Phase B, which are
90 degrees out of phase, allowing for edge counting to provide relative
position information.
index
Marker on an encoder that produces a single signal per revolution and is
typically used to establish a reference position.
L
limit switch/
end-of-travel position
(input)
Sensors that alert the control electronics that the physical end of travel is
being approached and that the motion should stop.
low
An input or output is low if the voltage is lower than the specified digital
logic low level.
low-side switch
A switch that provides a path to ground when closed.
M
microstep
Proportional control of energy in the coils of a stepper motor that
allow the motor to move to or stop at locations other than the fixed
magnetic/mechanical pole positions determined by the motor
specifications. This capability facilitates the subdivision of full mechanical
steps on a stepper motor into finer microstep locations that greatly smooth
motor running operation and increase the resolution or number of discrete
positions that a stepper motor can attain in each revolution.