Glossary of Terms
Resolution (encoder)
The number of full quadrature cycles per full shaft
revolution (360 mechanical degrees). Each cycle
can provide 1, 2, or 4 counts (i.e., X1, X2, and X4
decoding or multiplication) depending on how the
signal is decoded. Resolution is normally stated in
Shaft radial play
The total radial excursion of the shaft, measured
at a speci?ed distance from the front surface of the
component. A speci?ed radial load is applied
alternately in opposite directions at a speci?ed
point. Shaft radial play is expressed in inches.
pulses per revolution (PPR).
Shaft revolution
Resolution (potentiometer)
A measure of the sensitivity to which the output
One complete 360° turn of the shaft of a rotary
encoder in a single direction.
ratio of the potentiometer may be set.
Shaft runout
Rheostat
A variable resistor con?gured so that all the
current ?ows through the wiper.
Roll-on/Roll-off
The abrupt output voltage or resistance change
observed as the shaft is displaced from the end of
The eccentricity of the shaft diameter with respect
to the rotational axis of the shaft, measured at a
speci?ed distance from the end of the shaft. The
body of the potentiometer is held ?xed and the
shaft is rotated with a speci?ed load applied radial
to the shaft. The eccentricity is expressed in inches,
TIR.
mechanical travel into the electrical travel.
Solderability
Rotational life
The ability of a component to withstand a
speci?ed number of cycles under speci?c operating
conditions while remaining within allowable
The adhesion of molten solder to the terminals of
a component, producing a continuous coat of
solder without voids and pinholes under speci?ed
conditions.
speci?cations.
Starting torque
Running torque
The rotational force required to sustain uniform
shaft rotation at a speci?ed speed in the clockwise
or counterclockwise directions throughout the
The rotational force required to initiate shaft
rotation of a rotary component in the clockwise or
counterclockwise directions anywhere in the
mechanical travel.
mechanical travel.
State
Shaft
The mechanical input interface of the
The logic levels generated in the output signal of a
digital component (High, 1, true/Low, 0 false).
potentiometer.
Stop strength
70
Shaft endplay
The total axial excursion of the shaft, measured at
the end of the shaft with a speci?ed axial load
supplied alternately in opposite directions. Shaft
endplay is expressed in inches.
The maximum load that can be applied to the
shaft at each mechanical stop for a speci?ed period
of time without permanent change of the stop
positions greater than speci?ed.