AS37-H39B-Kxxx
39 Bits Battery Backup Multi-Turn Absolute Encoder
with RS-485 Half-Duplex Output
Data Sheet
Description
AS37-H39B series encoder is a high-resolution optical absolute
encoder produced by Avago Technologies, which offers 23-bits
single-turn and 16-bits multi-turn counts, hence a combined
39 bits high resolution. The AS37- H39B 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 Kxxx option of encoders is
preloaded with the Avago developed protocol with RS-485
standard compliance with provided CRC and alarm status bits.
The RS-485 half-duplex protocol is supported by a half-duplex
line transmissions drive (RS-485), offering good noise immunity
for more robust transmission of data at 2.5 Mbps in harsh
industrial application.
The key advantage of AS37-H39B series is multi-turn tracking
that employs battery backup technologies. It is the gearless
multi-turn counting that eliminates the gear worn out or
acoustics noise issue that is encountered in conventional
geared multi-turn encoders. Because the product is intended
for industrial application, ESD protection circuitry has been
designed by achieving the following ESD compliance:
IEC-61000-4-2 class 3.
battery life, extra effort has been put into the design of the
ASIC to ensure minimum current consumption during battery
mode operation. Therefore, no miscounts occur even in the
absence of external power supply.
Features
39-bits resolution: 16-bits battery backup multi-turn and
23-bits optical single-turn
Alarm features with CRC and alarm status bits
Built-in RS-485 half-duplex communication protocol
Ø37 mm and typical mounting height 28 mm
Supporting 8-mm diameter of the blind hollow and Taper
shaft
5K bits of user-accessible memory in E
2
PROM
Benefits
High resolution with higher measurement accuracy
Position detection during power failure with battery buffer
Immediate position detection on power up
Operating Theory
Structure-wise, the encoder contains two main functional
blocks: the single-turn optical engine block and the battery
backup multi-turn counter block. The single-turn engine
comprises the Avago developed high-performance optical
detector ASIC, which is accompanied by high-precision
amplifier circuitry, coupled with a special multi-track code disk
that rotates between the LED emitter and detector IC.
On multi-turn side, the multi-turn counting is enabled utilizing
battery backup counter technology. During battery mode
(encoder operates in main power OFF state), the battery
backup circuitry periodically powers up the LED emitter,
enabling the photo sensor to scan the code disk multi-turn
tracks for detection of shaft rotation. In order to prolong the
Applications
Robotics
Factory automation
Linear positioning system
CNC machine tool
Medical and lab equipment
Wind turbine
Avago Technologies 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.
NOTE
Broadcom
-1-
AS37-H39B-Kxxx
Data Sheet
Device Selection Guide
Device Selection Guide
Part Number
AS37-H39B
a.
b.
Resolution
39 bits (16 bits ST + 16 bits MT)
a
Operating
Temperature (°C)
–20 °C ~ 105 °C
b
Output
Communication
RS-485 half-duplex
Output Code
Binary
DC Supply
Voltage (V)
5.0 V ± 10%
ST: Single-turn; MT: Multi-turn.
Exposure to absolute maximum rating conditions for extended periods may affect reliability.
Electrical Specifications
Parameter
Current Consumption
Supply Voltage
Electrically Permissible Speed
Electrically Permissible Acceleration
Conditions
Without load,
Tamb = 25 °C
—
—
Normal mode
Battery mode
External Battery Supply Voltage
Battery Mode Current Consumption
—
Tamb = 25 °C
Min
—
4.5
—
—
—
3.6
—
Typ
110
5
—
—
—
—
95
Max
—
5.5
6,000
8.0 x 10
4
4.0 x 10
4
4.5
—
V
μA
Unit
mA
V
min
–1
rad/s
2
Mechanical Specifications
Parameter
System Accuracy
Mechanical Permissible Speed
Shaft Radial Play
Shaft Axial Play
Starting Torque
Conditions
With electrical correction,
Tamb = 25 °C
—
—
—
Tamb = 25 °C
Min
—
—
—
—
—
Typ
±80
—
—
—
—
Max
—
6,000
±0.05
±0.1
9.8 x 10
–3
Unit
Arc-sec
min
–1
mm
mm
N.m
Environmental Specifications
Parameter
Storage Temperature
Operating Temperature
Relative Air Humidity
(Non-Condensing)
Protection
Vibration
Shock
Conditions
—
—
Tamb = 40 °C
—
Per IEC 60068-2-6
Per IEC 60068-2-27
Min
–20
–20
—
—
—
—
Typ
—
—
90
IP40
—
—
Max
105
105
—
—
10G;
10 ~ 2000 Hz
6 ms; Half Sine;
200G
Unit
°C
°C
RH%
—
—
—
Broadcom
-5-
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