2
Absolute Maximum Ratings
Parameter Symbol Min. Max. Units Notes
Storage Temperature TS–40 85 ˚C
Operating Temperature TA–10 85 ˚C
Supply Voltage VCC –0.5 5 V
Output Voltage VO–0.5 VCC V
Output Current per Channel IO–0.2 9 mA
Definitions
(Note: Refer to the Appendix for
Signals Diagram.)
Count (N) = The number of bar
and window pairs or Counts Per
Revolution (CPR) of the code-
wheel, or the number of Lines Per
Inch of the codestrip (LPI).
1 Shaft Rotation
=360 mechanical degrees
= N cycles
1 cycles (c)
= 360 electrical degrees (˚e)
= 1 bar and window pair
Pulse Width (P): The number of
electrical degrees that an output
is high during one cycle. This
value is nominally 180˚e or 1/2
cycle.
Pulse Width Error (∆P): The
deviation, in electrical degrees, of
the pulse width from its ideal
value of 180˚e.
State Width (S): The number of
electrical degrees between a tran-
sition in the output of channel A
and the neighboring transition in
the output of channel B. There
are 4 states per cycle, each nomi-
nally 90˚e.
State Width Error (∆S): The
deviation, in electrical degrees, of
each state width from its ideal
value of 90˚e.
Phase (φφ
φφ
φ): The number of electri-
cal degrees between the center of
the high state of channel A and
the center of the high state of
channel B.
This value is nominally 90˚e for
quadrature output.
Phase Error (∆φφ
φφ
φ): the deviation
of the phase from its ideal value
of 90˚e.
Direction of Rotation: When
the codewheel or codestrip
moves in the direction from pin 1
to pin 4, as viewed when looking
down on the lenses, channel B
will lead channel A. If the
codewheel or codestrip moves in
the opposite direction, channel A
will lead channel B.
Optical Radius (Rop): For ro-
tary motion, the distance from
the codewheel’s center of rota-
tion to the center line connecting
the two lenses of the encoder.
Gap (G): The distance from the
top of the package to the surface
of the reflective codewheel or
codestrip.
Specular Reflectance (Rf): A
measure of a surface’s reflective
finish. This is quantified by the
amount of light reflected when hit
with an incident beam. A device
called a scatterometer is used to
quantify specular reflectance on a
percent scale. (Contact factory
for more information.)
Radial and Tangential Mis-
alignment Error ER, ET): For
rotary motion, mechanical mis-
alignment in the radial and tan-
gential directions relative to the
codewheel.
Angular Misalignment Error
(EA): Angular misalignment of
the sensor in relation to the tan-
gential direction. This applies for
both rotary and linear motion.