HEDS-9710-150 Avago Technologies US Inc., HEDS-9710-150 Datasheet - Page 2

• Manufacturer Part Number: HEDS-9710-150
• Description: ENCODER SMALL 2CH 360LPI STR LD
• Manufacturer: Avago Technologies US Inc.
• Series: HEDSr

Specifications of HEDS-9710-150

• Termination Style: Terminal Pins
• Encoder Type: Optical
• Output Type: Quadrature (Analog)
• Pulses Per Revolution: 360 LPI
• Voltage - Supply: 5VDC
• Actuator Type: Codestrip Not Included
• Detent: No
• Built In Switch: No
• Mounting Type: Chassis Mount
• Orientation: Vertical
• Number Of Channels: 2
• Mounting Style: PCB
• Supply Voltage: 5 V
• Product: Optical
• Technology: Rotary
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Rotational Life (cycles Min): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Theory of Operation
An HEDS-971x is a C-shaped
emitter/detector module.
Coupled with a codewheel, it
translates rotary motion into a
two-channel digital output,
coupled with a codestrip; it
translates linear motion into
digital outputs.
As seen in the block diagram,
the module contains a single
Light Emitting Diode (LED) as
its light source. The light is
collimated into parallel beam by
means of a single lens located
directly over the LED. Opposite
the emitter is the integrated
detector circuit. This IC consists
of photodetectors and a signal
processing circuitry necessary to
produce the digital waveforms.
The codewheel/codestrip moves
between the emitter and
detector, causing the light beam
to be interrupted by the pattern
of spaces and bars on the
codewheel/codestrip. The photo-
diodes, which detect these
interruptions, are arranged in a
pattern that corresponds to the
radius and count density of the
codewheel/codestrip. These
photodiodes are also spaced
such that a light period on one
pair of detectors corresponds to
a dark period on the adjacent
pairs of detectors. The
photodiode outputs are fed
through the signal processing
circuitry. Two comparators
receive these signals and
2
produce the final outputs for
Channels A and B. Due to this
integrated phasing technique the
output of channel A is in
quadrature with Channel B (90
degrees out of phase).
Definitions
Count (N): The number of bar
and window pairs or counts per
revolution (CPR) of the
codewheel, or the number of
lines per inch of the codestrip
(LPI).
1 shaft Rotation = 360 degrees
1 cycle (c) = 360 electrical
degrees, equivalent to 1 bar and
window pair.
Pulse Width (P): The number of
electrical degrees that an output
is high during one cycle,
nominally 180 e or 1/2 a cycle.
Pulse Width Error (DP): 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
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.
State Width Error (DS): The
deviation in electrical degrees of
each state width from its ideal
value of 90 e.
= N cycles
Phase (f): The number of
electrical degrees between the
center of the high state on
channel A and the center of the
high state on channel B. This
value is nominally 90 e for
quadrature output.
Phase Error (Df): The deviation
in electrical degrees of the phase
from its ideal value of 90 e.
Direction of Rotation: When
the codewheel rotates in the
counter-clockwise direction (as
viewed from the encoder end of
the motor), channel A will lead
channel B. If the codewheel
rotates in the clockwise
direction, channel B will lead
channel A.
Optical Radius (Rop): The
distance from the codewheel’s
center of rotation to the optical
center (O.C) of the encoder
module.
Angular Misalignment Error
(E
the sensor in relation to the
tangential direction. This applies
for both rotary and linear
motion.
Mounting Position (R
Distance from Motor Shaft
center of rotation to center of
Alignment Tab receiving hole.
A
): Angular misalignment of
M
):