HEDS-8905 Avago Technologies US Inc., HEDS-8905 Datasheet - Page 2

• Manufacturer Part Number: HEDS-8905
• Description: TOOL ALIGNMENT 3CH 28MM CW
• Manufacturer: Avago Technologies US Inc.

Specifications of HEDS-8905

• Accessory Type: Mechanical Alignment Tool
• Product: Tools & Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: HEDS-914x Series
• For Use With: HEDS-9141#G00 - ENCODER MODULE 3CH 360CPRHEDS-9141#F00 - ENCODER MODULE 3CH 256CPRHEDS-9141#E00 - ENCODER MODULE 3CH 200CPRHEDS-9141#A00 - ENCODER MODULE 3CH 500CPRHEDS-9140#S00 - ENCODER MODULE 3CH 50CPRHEDS-9140#I00 - ENCODER MODULE 3CH 512CPRHEDS-9140#H00 - ENCODER MODULE 3CH 400CPRHEDS-9140#G00 - ENCODER MODULE 3CH 360CPRHEDS-9140#F00 - ENCODER MODULE 3CH 256CPRHEDS-9140#E00 - ENCODER MODULE 3CH 200CPRHEDS-9140#C00 - ENCODER MODULE 3CH 100CPRHEDS-9140-B00 - ENCODER MODULE 3CH 1000CPR516-1888 - ENCODER OPTICAL GAP 3CH 500CPR
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

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The HEDS-9040 and 9140 have two channel quadrature
outputs plus a third channel index output. This index
output is a 90 electrical degree high true index pulse
which is generated once for each full rotation of the
codewheel.
The HEDS-9040 is designed for use with a HEDX-614X
code wheel which has an optical radius of 23.36 mm
(0.920 inch). The HEDS-9140 is designed for use with a
HEDx-5x4x code wheel which has an optical radius of
11.00 mm (0.433 inch).
The quadrature signals and the index pulse are accessed
through fi ve 0.025 inch square pins located on 0.1 inch
centers.
Standard resolutions between 256 and 2000 counts per
revolu tion are available. Consult local Avago sales repre-
sentatives for other resolutions.
Applications
The HEDS-9040 and 9140 provide sophisticated motion
control detection at a low cost, making them ideal for
high volume applications. Typical applica tions include
printers, plotters, tape drives, and industrial and factory
automation equipment.
Note: Avago Technologies encoders are not recommend-
ed for use in safety critical applications. Eg. ABS braking
systems, power steering, life support systems and critical
care medical equipment. Please contact sales represen-
tative if more clarifi cation is needed.
Theory of Operation
The HEDS-9040 and 9140 are emitter/detector modules.
Coupled with a codewheel, these modules translate the
rotary motion of a shaft into a three-channel digital out-
put.
As seen in the block diagram, the modules contain a
single Light Emitting Diode (LED) as its light source. The
light is collimated into a parallel beam by means of a
single poly car bon ate lens located directly over the LED.
Opposite the emitter is the integrated detector circuit.
This IC consists of multiple sets of photodetec tors and
the signal processing circuitry necessary to produce the
digital waveforms.
The codewheel rotates between the emitter and detector,
causing the light beam to be interrupted by the pattern
of spaces and bars on the code wheel. The photo diodes
which detect these interrup tions are arranged in a pat-
tern that corresponds to the radius and design of the
code wheel. These detectors are also spaced such that a
light period on one pair of detectors corresponds to a
dark period on the adjacent pair of detectors. The photo-
diode outputs are then fed through the signal process-
ing circuitry resulting in A, A, B, B, I and I. Comparators
receive these signals and produce the fi nal outputs for
channels A and B. Due to this integrated phasing tech-
nique, the digital output of channel A is in quadrature
with that of channel B (90 degrees out of phase).
The output of the comparator for I and I is sent to the in-
dex processing circuitry along with the outputs of chan-
nels A and B. The fi nal output of channel I is an index
pulse P
the codewheel. This output P
nally 90 electrical degrees), high true index pulse which
is coincident with the low states of channels A and B.
O
which is generated once for each full rotation of
O
is a one state width (nomi-