AS38-H39E Series
39-Bit Energy-Harvesting Multi-Turn Absolute
Encoder
Data Sheet
Introduction
The AS38-H39E series encoder is a high-resolution optical
absolute encoder produced by Broadcom®, which offers 23-bit
single-turn and 16-bit multi-turn counts, hence a combined
39-bit high resolution. The AS38-H39E series encoder is a
house encoder consisting of a patterned disk, a light source,
and photosensitive elements to translate the mechanical
motion into electrical signal.
The AS38-H39E series encoder has a built-in communication
protocol that is supported by a full-duplex or half-duplex line
transmissions drive, offering good noise immunity for more
robust transmission of data up to 10 Mb/s in harsh industrial
application. Because the product is intended for industrial
application, ESD protection circuitry has been designed in to
achieve Class 3 ESD immunity per IEC -61000-4-2 standard. The
AS38-H39E series is also compliant with IP50 per IEC 60529
standard.
The key advantage of the AS38-H39E series is its multi-turn
tracking that employs energy-harvesting technology by
harvesting the magnetic energy as the encoder shaft rotates. It
is the gearless multi-turn counting that eliminates the gear
wear-out or acoustics noise issue that is encountered in
conventional geared multi-turn encoder. On the other hand,
when comparing to battery backed up multi-turn counting,
this technology does not require periodic maintenance of the
battery backup components and the down time associated
with it.
rotating, the magnet mounted on the shaft moves in tandem.
The energy-harvesting coil module cuts the moving magnet
field, and generates energy as a result.
The beauty of the energy-harvesting effect is that the same
amount of energy is generated independent of the rotation
speed. The generated energy is sufficient to power up the
revolution tracking circuitry. Therefore, no miscounts occur
even in the absence of external power supply.
Features
39-bit resolution: 16-bit energy-harvesting multi-turn and
23-bit optical single-turn
Built-in communication protocol (option): BiSS C mode, SSI
mode and RS-485 half-duplex
Overall encoder outer diameter Ø38 mm and maximum
height of 40 mm
Supporting ¼ inch, 6-mm and 8-mm diameter of the blind
hollow shaft
Benefits
No battery or capacitor required for position detection
during power failure
Immediate position detection on power up
Applications
Operating Theory
Structures-wise, the encoder contains two main functional
blocks: the single-turn optical engine block and the
energy-harvesting multi-turn counter block. The single-turn
engine comprises a Broadcom developed high-performance
optical detector ASIC, which is accompanied by high-precision
amplifiers circuitry, coupled with a special multi-track code disk
that rotates between the LED emitter and detector IC.
On the multi-turn side, the multi-turn counting is enabled
utilizing energy-harvesting technology. When the shaft is
Robotics
Factory automation
Linear positioning system
CNC machine tool
Medical and lab equipment
NOTE
Broadcom encoders are not recommended
for use in safety critical applications, e.g., ABS
braking systems, power steering, life support
systems, and critical care medical equipment.
Contact a sales representative if more
clarification is needed.
Broadcom
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