Agilent AEAS-72AC-xxxxB
Absolute Encoder
Data Sheet
Features
• Gray or binary code options
• High or low power source options
• IP 65 rating
• 50 mm package diameter
• 8 mm in hollow shaft diameter
• The package comes with
2 m long cable
Applications
• Tool changers and axis control for
machine tools
• Robotics
• Telescopes and antennas
• Rotary and X - Y positioning tables
• Medical scanners
Description
The AEAS-72AC-xxxxB absolute
encoder is a feedback device that
has the capability to generate a
unique binary ‘word’ for each
encoder shaft position. The AEAS-
72AC-xxxxB also has the unique
feature of being able to provide
positional information upon power
up without the need for codewheel
movement, unlike incremental
encoders, which need codewheel
movement to provide positional
information.
Each absolute encoder from the
AEAS-72AC-xxxxB consists of a
lensed LED (Light Emitting Diode)
source, an integrated circuit with
detectors and output circuitry,
and a special multi-track glass
codewheel that rotates between
the emitter and detector IC.
These 3 main components are
contained within a strong metal
housing fitted with bearings to
produce an IP rated encoder
capable of working in very wet
and dusty conditions. Models
with IP65 ratings have sealed
bearings.
2
20
20
50 ± 0.2 8h7
2 m
40 MAX.
10
35
13 ± 0.2
10 ± 0.2
120° 120°
7 ± 0.2
PCD 40
3-M4 DEPTH 5
ZERO POSITION
5 ± 0.1
15 ± 0.3
30h7
TYPICAL DIMENSIONS IN MILLIMETERS.
Package Dimensions
3
SHAFT
FIXED SLIT
CODEWHEEL
LED
PHOTODIODE IC
Theory of Operation
The AEAS-72AC-xxxxB is a low-
cost and compact absolute encoder
which uses optical technology to
provide absolute positioning
information.
The AEAS-72AC-xxxxB consists of
a LED, Fixed Slit, Codewheel
(Rotating Disc) and Photodiode IC.
By using these four main compo-
nents, the AEAS-72AC-xxxxB is
able to produce signals in either
binary or gray output form. These
signals provide to the designer a
unique code for each position that
the codewheel is in.
As seen in the diagram, the encoder
contains a single Light Emitting
Diode (LED) as its light source.
The light is collimated into a
parallel beam by means of a lens
which is built into the LED
housing. This parallel beam goes
through the Fixed Slit that creates
a certain light pattern, due to its
pattern of slots, which will fall onto
the code-wheel. The movement of
the code-wheel between LED and
Photo detector, causes the light
pattern (from the Fixed Slit) to be
further interrupted by the pattern
of spaces and bars on the
codewheel. This final light pattern
from the codewheel is then
detected by the Photodiode IC
where its signals are fed through
signal processing circuitry to
produce 8 or 10 parallel signals in
binary or gray output form.
4
Absolute Maximum Ratings
Storage Temperature –30°C to 85°C
Operating Temperature –10°C to 60°C
Supply Voltage DC4.5 V to 13.2 V (for output mode = V)
DC4.5 V to 13.2 V; DC10.8 V to 26.4 V (for output mode = C)
DC10.8 V to 26.4 V )for output mode = P)
(note: VCC ripple at 3% p-p max.)
Humidity RH85%
Degree of Protection (IP65): Totally protected against dust and protected against low-pressure
jets of water from all directions; limited ingress permitted.
Shock 980 m/s2 with 11 ms at X, Y, Z directions
Electrical Characteristics (over recommended operating conditions. Typically at 25°C)
Parameter Symbol Maximum Units
Current Consumption (without load) ICC 100 m (max.) A
High Level Output Voltage VOH VCC– 1 V (for output mode = V) V
Low Level Output Voltage VOL 0.5 or less (for output mode V, C) V
Rise Time tr2µs
Fall Time tf2µs
Response Frequency f 10 K (for 8 bit resolution) Hz
20 K (for 10 bit resolution)
Angular Accuracy ± 0.700° (max. for 8 bit resolution) deg
± 0.175° (max. for 10 bit resolution)
Mechanical Characteristics
Parameter Typical/Maximum Units
Starting Torque 9.8 10–3 (max. at 25°C) Nm
Angular Acceleration 1 × 105rad/s2
Shaft Loading Axial Thrust 49 N
Radial 78.4 N
Moment of Inertia 30 g.cm2
Speed Typical = 3000 RPM
Maximum = 5000
Net-Weight (without cable) 250 (max.) g
Vibration (in X, Y, Z directions for 2 hrs.) 10 to 55 Hz/1.5 mm (p-p)
5
Electrical Interface
SIGNAL
V
CC
0 V
OPEN COLLECTOR OUTPUT
OUTPUT MODE
C
SIGNAL
V
CC
0 V
VOLTAGE OUTPUT
OUTPUT MODE
V
2 KΩ
SIGNAL
V
CC
0 V
PNP OPEN COLLECTOR OUTPUT
OUTPUT MODE
P
6
Output Waveforms Definition
Signals are extracted by rotating
the shaft in clockwise direction as
viewed from arrow angle.
H
L
20
H
L
21
H
L
22
H
L
23
H
L
24
H
L
25
H
L
26
H
L
27
012345678910
7
Electrical Connections
Color of Lead Wire Description
Red Power Source
Black 0 V Common
Brown Signal 20
Orange Signal 21
Yellow Signal 22
Green Signal 23
Blue Signal 24
Purple Signal 25
Gray Signal 26
White Signal 27
Pink Signal 28 Only available for 1024 split type
Sky Blue Signal 29 Only available for 1024 split type
Shielding Braid FG
AEAS-72AC- B
Power Source
L = 5 to 12 V
H = 12 to 24 V
Ordering Information
Output Code
G = Gray Code Negative Logic
A = Binary Code Negative Logic
Output Mode
C = Open Collector
P = PNP Open Collector
V = Voltage Out, only for
5 to 12 V power source
Resolution
A = 8 bits
B = 10 bits
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For product information and a complete list of
distributors, please go to our web site.
For technical assistance call:
Americas/Canada: +1 (800) 235-0312 or
(408) 654-8675
Europe: +49 (0) 6441 92460
China: 10800 650 0017
Hong Kong: (+65) 6271 2451
India, Australia, New Zealand: (+65) 6271 2394
Japan: (+81 3) 3335-8152(Domestic/Interna-
tional), or 0120-61-1280(Domestic Only)
Korea: (+65) 6271 2194
Malaysia, Singapore: (+65) 6271 2054
Taiwan: (+65) 6271 2654
Data subject to change.
Copyright © 2002 Agilent Technologies, Inc.
August 1, 2002
5988-7361EN
