AEDx-8xxx-xxx
2- or 3-Channel Incremental Encoder Kit with Codewheel
Data Sheet
Description
The AEDx-8xxx comes in an option of two-channel or
three-channel optical incremental encoder kit with code-
wheel integrated in a protective housing. The encoder is
lead free and compliant to the RoHS directive. Each en-
coder kit consists of a collimated LED source and a detec-
tor IC enclosed within a small plastic package.
The AEDx-8xxx optical encoder has two-channel quadra-
ture outputs (A,B) plus a third channel index output (I).
There are three index options available. i.e. ungated, gat-
ed-90 ° and gated-180 ° electrical degree index pulse.
The AEDx-8xxx series optical encoder is designed for use
with motors with shaft diameters of 2mm and up to 5mm.
The quadrature, index and power supplied to the encoder
are accessed through an 8-pin male connector of 1.25 mm
pitch.
The AEDx-8xxx solution enables the servo system to be
more compact. With the aid of alignment jig, the assembly
process will also require less alignment time, thus making
the assembly process much easier for servo motor inte-
gration.
Features
•
3-channel differential output (A,B) with ungated, gated-
90 ° and gated-180 ° index pulse (I)
•
2-channel differential output available
•
Up to 500 Cycles Per Revolution (CPR)
•
Up to 30000 rpm motor speed
•
-40 °C to 100 °C operating temperature
•
Single 5 V supply
•
Integrated RS-422 line driver
•
Quick and easy assembly
Assembly View
Housing
Applications
The AEDx-8xxx provides motion detection for DC servo
motor and closed loop stepper motor feedback system in
the following applications:
•
Pick and Place machines
•
Semiconductor equipment
•
Factory automation equipment
Sensor Chassis
Codewheel & Hub
Baseplate
Note:
Avago Technologies encoders are not recommended for use in safety critical applications, e.g., ABS braking sys-
tems, power steering, life support systems and critical care medical equipment. Avago’s products and software are not
specifically designed, manufactured or authorized for sale as parts, components or assemblies for the planning, con-
struction, maintenance or direct operation of a nuclear facility or for use in medical devices or applications. Customers
are solely responsible, and waive all rights to make claims against Avago or its suppliers, for all losses, damage, expense
or liability in connection with such use. Please contact your local sales representative if more clarification is needed.
Theory of Operation
The AEDx-8xxx optical encoder is a housed solution with
integrated encoder and codewheel. The encoder trans-
lates the rotary motion of a shaft into incremental digital
outputs.
The encoder contains a single Light Emitting Diode (LED)
as the light source. The light is collimated into a parallel
beam by means of polycarbonate lens located directly
over the LED. Opposite the emitter is a detector IC. This
IC consists of multiple sets of photo detectors and signal
processing circuitry necessary to produce the digital wave-
form output. The codewheel rotates between the emitter
and detector, causing the light beam to be interrupted by
pattern of spaces and bars on the codewheel. The Photo-
diodes that detect these interruptions are arranged in a
pattern that corresponds to the radius and design of the
codewheel. These detectors are also spaced in such way
that light period on one pair of detectors corresponds to
dark period on adjacent pair of detectors. The photodiode
outputs are then fed through the signal processing circuit-
ry that produce the final outputs for channel A and B. Due
to this integrated phasing technique, the digital output of
channel A is in quadrature with that of channel B (90 elec-
trical degrees out of phase). As a standard, the outputs are
fed through a standard RS422 line driver to deliver the dif-
ferentials signals at the final encoder output.
Definitions
Cycles (N):
The number of electrical cycles per revolution
(CPR).
Note:
CPR refers to the raw signal from encoder, that is
the cycles before 4x decode.
One Cycle:
360 electrical degrees (°e).
One Shaft Rotation:
360 mechanical degrees.
Cycle Error (∆C):
An indication of cycle uniformity. The dif-
ference between an observed shaft angle which gives
rise to one electrical cycle, and the nominal angular
increment of 1/N of a revolution.
Pulse Width (P):
The number of electrical degrees that an
output is high during 1 cycle. This value is nominally
180°e or 1/2 cycle.
Pulse Width Error (∆P):
The deviation, in electrical degrees,
of the pulse width from its ideal value of 180°e.
State Width (S):
The numbers of electrical degrees be-
tween transitions 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 (∆S):
The deviation, in electrical degrees,
of each state width from its ideal value of 90°e.
Phase (Φ):
The numbers of electrical degrees between
the center of the high state of channel A and the center
of the high state of channel B. This value is nominally
90°e for quadrature output.
Phase Error (∆φ):
The deviation of the phase from its ideal
value of 90°e.
Index Pulse Width (Po):
The number of electrical degrees
that an index is high with reference to channel A or
channel B during one full shaft rotation.
Absolute Maximum Ratings
[1,2]
Parameter
1.
2.
3.
4.
5.
6.
Storage Temperature AEDS Series
Storage Temperature AEDT Series
Supply Voltage
Output Voltage
Output Current per Channel
Shaft Axial Play
Shaft Radial Play Plus Eccentricity
Symbol Min.
T
S
T
S
Vcc
Vout
Iout
-20
-40
-0.5
-0.5
-
-
-
Max.
85
100
7
Vcc
± 150
Units
°C
°C
V
V
mA
± 0.100 mm
± 0.080 mm
Note:
1. Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the
device should be operated at these limits.
2.
Stresses greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to absolute maximum
rating conditions for extended periods may affect reliability.
2
Recommended Operating Conditions
Parameter
1.
2.
3.
4.
Operating Temperature AEDS Series
Operating Temperature AEDT Series
Supply Voltage
Output frequency ( 200 CPR)
Output frequency ( 400 & 500 CPR)
Symbol
T
A
T
A
V
cc
f
Min.
-20
-40
4.5
-
-
Typ.
-
-
5.0
-
-
Max.
85
100
5.5
100
200
Units
°
C
°
C
V
kHz
Notes
Velocity(rpm) x N/60
Encoding Characteristics (Vcc = 4.5 to 5.5V, Tamb = -40 to +100°C)
AEDx-8xxx-Exx (200 CPR only)
Parameter
1.
2.
3.
4.
5.
Pulse Width Error
State Width Error
Phase Error
Cycle Error
Index Pulse Width Un-gated
Index Pulse Width Gated 90°e
Index Pulse Width Gated 180°e
6.
Position Error
Note 3: Typical values specified at Vcc = 5.0V and 25°C
Symbol
∆P
∆S
∆φ
∆C
Po
Po
Po
∆Θ
Min.
-
-
-
-
220
60
140
-
Typ.(3)
5
3
2
5
360
90
180
15
Max
35
35
20
15
500
120
220
50
Units
°e
°e
°e
°e
°e
°e
°e
min. of arc
Notes
Encoding Characteristics (Vcc = 4.5 to 5.5V, Tamb = -40 to +100°C)
AEDx-8xxx-xxx (400 & 500CPR)
Parameter
1.
2.
3.
4.
5.
Pulse Width Error
State Width Error
Phase Error
Cycle Error
Index Pulse Width Un-gated
Index Pulse Width Gated 90°e
Index Pulse Width Gated 180°e
6.
Position Error
Note 3: Typical values specified at Vcc = 5.0V and 25°C
Symbol
∆P
∆S
∆φ
∆C
Po
Po
Po
∆Θ
Min.
-
-
-
-
220
50
135
-
Typ.(3)
7
5
2
7
360
90
180
20
Max
60
60
35
30
500
130
225
60
Units
°e
°e
°e
°e
°e
°e
°e
min. of arc
Notes
Electrical Characteristics (V
CC
= 4.5 to 5.5V, T
amb
= -40 to +100°C)
Parameter
1.
2.
3.
4.
5.
6.
Supply Current
Output High Level
Output Low Level
Output Current
Rise time
Fall time
Symbol
I
CC
V
OH
V
OL
I
O
t
r
t
f
Min.
-
2.5
-
-
-
-
Typ.
[1]
42
3.4
0.3
25
30
30
Max
50
-
0.5
40
100
100
Units
mA
V
V
mA
ns
ns
Notes
Io = -20mA
Io = 20mA
Note:
1. Typical values specified at Vcc = 5.0V and 25°C.
3
Pin 1
Pin
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
Pin 8
Signal
GND
A+
A-
B+
B-
I+
I-
Vcc
Description
Ground
Digital Output
Digital Output
Digital Output
Digital Output
Digital Output
Digital Output
Voltage Input
Output Waveforms
P
C
2.5 V
0.5 V
S1
φ
S2
S3
S4
2.5 V
0.5 V
2.5 V
0.5 V
Po
2.5 V
0.5 V
2.5 V
0.5 V
Po
2.5 V
0.5 V
2.5 V
0.5 V
Po
2.5 V
0.5 V
2.5 V
0.5 V
CH. A
CH. B
CH. I
CH. I-
Gated 180°e
CH. I
CH. I-
Gated 90°e
CH. I
CH. I-
Ungated
CH. A-
2.5 V
0.5 V
CH. B-
Figure 1. Output waveforms for counter-clockwise rotation, viewed from the top of the encoder.
4
Pin 8
Pin Assignments
Direction of Motor Rotation
Direction of Rotation: When the codewheel rotates in the counter-clockwise direction viewing from the top of the en-
coder kit, channel A will lead channel B. If the codewheel rotates in the opposite direction, channel B will lead channel
A.
Electrical Interface
26LS31
Note:
OUTPUT+ represents A+, B+, or I+ digital output from the encoder.
OUTPUT- represents A-, B-, or I- digital output from the encoder.
Load resistance *RT is optional although highly recommended to reduce reflection.
Package Dimensions
Dimensions in mm unless otherwise stated.
Tolerance: +/- 0.1mm
Figure 2. Mechanical Dimensions for Mounting Option 1 (AEDx-8x0x)
5
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