3
Output Waveforms
State Width Error (∆S): The
deviation, in electrical degrees, of
each state width from its ideal
value of 90°e.
Phase (φ): The number of
electrical 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 (∆φ): The deviation
of the phase from its ideal value
of 90°e.
angle which gives rise to one
electrical cycle, and the nominal
angular increment of 1/N of a
revolution.
Definitions
Count (N): The number of bar
and window pairs or counts per
revolution (CPR) of the
codewheel.
Direction of Rotation: When the
codewheel rotates in the direction
of the arrow on top of the
module, channel A will lead
channel B. If the codewheel
rotates in the opposite direction,
channel B will lead channel A.
Pulse Width (P): The number of
electrical degrees that an output
is high during 1 cycle. This value
is nominally 180°e or 1/2 cycle.
One Cycle (C): 360 electrical
degrees (°e), 1 bar and window
pair.
Optical Radius (ROP ): The
distance from the codewheel's
center of rotation to the optical
center (O.C.) of the encoder
module.
Pulse Width Error (∆ P): The
deviation, in electrical degrees, of
the pulse width from its ideal
value of 180°e.
One Shaft Rotation: 360
mechanical degrees, N cycles.
Position Error (∆Θ): The
normalized angular difference
between the actual shaft position
and the position indicated by the
encoder cycle count.
State Width (S): The number of
electrical degrees between a
transition in the output of channel
A and the neighboring transition
in the output of channel B. There
are 4 states per cycle, each
nominally 90°e.
Index Pulse Width (PO ): The
number of electrical degrees that
an index is high during one full
shaft rotation. This value is
Cycle Error (∆C): An indication
of cycle uniformity. The differ-
ence between an observed shaft
nominally 90°e or 1/4 cycle.
Absolute Maximum Ratings
Storage Temperature, TS ............................................................. -40°C to +100°C
Operating Temperature, TA ........................................................ -40°C to +100°C
Supply Voltage, VCC ............................................................................... -0.5 V to 7 V
Output Voltage, VO ................................................................................. -0.5 V to VCC
Output Current per Channel, IOUT............................................ -1.0 mA to 5 mA
Shaft Axial Play................................................ ± 0.25 mm (± 0.010 in.)
Shaft Eccentricity Plus Radial Play.....................0.1 mm (0.004 in.) TIR
Velocity........................................................................... 30,000 RPM[1]
Acceleration .............................................................250,000 rad/sec2[1]
Note:
1. Absolute maximums for HEDS-5140/6140 codewheels only.
HP [ HEWLETT-PACKARD ]
