AEDT-9140 Series
High Temperature 115qC
Three Channel Optical Incremental Encoder Modules
100 CPR to 1000 CPR
Data Sheet
Description
Features
The AEDT-9140 series are three channel optical incremental encoder modules. When used with a codewheel, these
low cost modules detect rotary position. Each module
consists of a lensed LED source and a detector IC enclosed
in a small plastic package. Due to a highly collimated light
source and a unique photodetector array, these modules
are extremely tolerant to mounting misalignment.
x Two channel quadrature output with index pulse
The AEDT-9140 has 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.
x Small size
The AEDT-9140 optical encoder is designed for use with a
codewheel which has an optical radius of 11.00 mm (0.433
inch) for 100 CPR to 1000 CPR and 11.68 mm (0.460 inch)
for 1000 CPR.
The quadrature signals and the index pulse are accessed
through five 0.46 mm square pins located on 1.27 mm
(pitch) centers.
x Resolution from 100 CPR to 1000 CPR (Cycles Per
Revolution)
x Low cost
x Easy to mount
x No signal adjustment required
x -40qC to 115qC operating temperature
x TTL compatible
x Single 5V supply
Applications
Typical applications include:
x Printers
x Plotters
x Tape drives
x Machine tools
x Industrial and factory automation equipment.
Note: Avago Technologies encoders are not recommended for use in
safety critical applications. Eg. ABS braking systems, power steering, life
support systems and critical care medical.
Theory of Operation
Definitions
The AEDT-9140 is an emitter/detector module. Coupled
with a codewheel, these modules translates rotary motion
of a shaft into a three-channel digital output.
Note: Refer to Figure 2
As seen in Figure 1, 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 polycarbonate lens located directly over the LED. Opposite the
emitter is the integrated detector circuit. This IC consists
of multiple sets of photodetectors 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 codewheel.
The photodiodes which detect these interruptions are
arranged in a pattern 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 photodiode outputs are then fed through the signal
processing circuitry resulting in A, A-bar, B, B-bar, I and Ibar. Comparators receive these signals and produce the
final output for channels A and B. Due to this integrated
phasing technique, the digital output of channel A is
in quadrature with that of channel B (90 degrees out of
phase).
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 (C): 360 electrical degrees (qe).
One Shaft Rotation: 360 mechanical degrees, N cycles.
Cycle Error ('C): An indication of cycle uniformity. The difference 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 (S): 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 number of electrical degrees between a
transition 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 Error ('I): The deviation of the phase from its ideal
value of 90°e.
Direction of Rotation: When the codewheel rotates in the
clockwise direction viewing from top of the module (direction from V to G), channel A will lead channel B. If the
codewheel rotates in the opposite direction, channel B
will lead channel A.
Optical Radius (Rop): The distance from the codewheel’s center of rotation to the optical center (O.C) of the encoder
module.
Index Pulse Width (Po): The number of electrical degrees that
an index is high during one full shaft rotation. This value is
nominally 90qe or 1/4 cycle.
2
Block Diagram
VCC
RESISTOR
LENS
PHOTO
DIODES
COMPARATORS
A
A
CH. A
B
B
CH. B
LED
CH. I
I
I
INDEX
PROCESSING
CIRCUITRY
SIGNAL PROCESSING
CIRCUITRY
EMITTER SECTION
Figure 1.
Output Waveforms
Figure 2.
3
CODE
WHEEL
DETECTOR SECTION
GND
AEDT-9140 Technical Specifications
Absolute Maximum Ratings
Parameter
Symbol
Min.
Max.
Units
Storage Temperature
TS
-40
115
°C
Operating Temperature
TA
-40
115
°C
Supply Voltage
VCC
-0.5
7
Volts
Output Voltage
VO
-0.5
VCC
Volts
Output Current per Channel, Iout
IOUT
-1.0
18
mA
Notes
Recommended Operating Conditions
Parameter
Symbol
Min.
Temperature
TA
-40
Supply Voltage
VCC
4.5
Load Capacitance
Frequency
Typ.
Max.
Units
115
°C
5.5
Volts
Ripple < 100mVp-p
CL
100
pF
2.7 kΩ pull-up
f
100
kHz
Velocity (rpm) x N/60
Shaft Perpendicularity
Plus Axial Play
r 0.20
(r 0.008)
mm
(in.)
Refer to Mounting Consideration
Shaft Eccentricity
Plus Radial Play
0.04
(0.0015)
mm
(in.)
Refer to Mounting Consideration
5.0
Notes
Electrical Characteristics
Electrical characteristics over recommend operating range, typical at 25qC.
Parameter
Symbol
Min.
Typ
Max.
Units
Supply Current
ICC
30
57
85
mA
High Level Output Voltage
VOH
2.4
Low Level Output Voltage
VOL
Rise Time
tr
Fall Time
tf
Note: Typical values specified at Vcc = 5.0 V and 25 °C
4
Notes
V
Typ. IOH = -0.5 mA
V
Typ. IOL = 10 mA
180
ns
50
ns
CL = 25 pF
RL = 2.7 k: pull-up
0.4
Encoding Characteristics
AEDT-9140 (except – B0B)
Encoding Characteristics over the recommended operating conditions and recommended mounting tolerances unless
otherwise specified.
Parameter
Symbol
Cycle Error
Min.
Typ.
Max.
Units
∆C
3
15
°e
Pulse Width Error
∆P
7
30
°e
Logic State Width Error
∆S
5
30
°e
Phase Error
∆φ
2
15
°e
Position Error
∆Θ
10
40
min. of arc
Index Pulse Width
Po
60
90
120
°e
CH I rise after
CH B or CH A fall
-40°C to + 115°C
t1
10
100
1000
ns
CH I rise after
CH A or CH B rise
-40°C to + 115°C
t2
10
300
1000
ns
Encoding Characteristics
AEDT-9140-B0B & AEDT-9140-B00
Encoding characteristics over the recommended operating conditions and recommended mounting tolerances unless
otherwise specified.
Parameter
Typ.
Max.
Units
∆C
3
6
15
20
°e
Pulse Width Error
∆P
7
50
°e
Logic State Width Error
∆S
5
50
°e
Phase Error
∆φ
2
15
°e
Position Error
∆Θ
10
40
min. of arc
Index Pulse Width
Po
40
90
120
°e
-40°C to + 115°C
t1
10
450
1500
ns
CH I rise after
-40°C to + 115°C
CH A or CH B rise
t2
10
250
1500
ns
Cycle Error
Symbol
- B0B option
- B00 option
CH I rise after
CH B or CH A fall
5
Min.
Electrical Interface
To ensure reliable encoding performance, the AEDT-9140
three channel encoder modules require 2.7 kΩ (± 10%)
pull-up resistors on output pins 2, 3, and 5 (Channels A, I
and B) as shown in Figure 3. These pull-up resistors should
be located as close to the encoder module as possible
(within 4 feet). Each of the three encoder module outputs
can drive a single TTL load in this configuration.
Figure 3.
Customized Solutions
CPR calculation formula:
Customization of codewheel CPR is possible. It has to be
based on the encoder LPI table given below.
CPR = LPI x 2 x S x ROP
25.4
Part Number
LPI
Where:
AEDT-9140-C00
36.7
CPR = Counts Per Revolution
AEDT-9140-E00
73.5
LPI = Encoder LPI provided in the table
AEDT-9140-F00
94
ROP = Encoder Optical Radius in mm
AEDT-9140-G00
132.3
AEDT-9140-H00
147
* Recommended maximum codewheel diameter should
not exceed 30mm.
AEDT-9140-A00
183
AEDT-9140-I00
188
AEDT-9140-B0B
346
AEDT-9140-B00
367.5
6
Note: The customization of the codewheel method is valid from theoretical standpoint. However Avago strongly recommends a full characterization to be done to determine the actual performance of the encoder
with customized codewheel.
Characterization means validating the encoding performance (consist
of cycle error, pulse width error, logic state width error, phase error, position error & index pulse width, index channel rise and fall time over
the recommended operating conditions and recommended mounting
tolerances.
Mounting Considerations
SHAFT
CENTER
AXIS
OPTICAL
CENTER
AXIS
ARTWORK
GAP TYPICAL
0.50
EG
R0.89
Codewheel
MOUNTING PLANE
Rop
MOUNTING BOSS
2MM DIA.
2 PLACES
6.30
ET
OPTICAL CENTER AXIS
12.60
Recommended Screw Size: M1.6 x 0.35
Recommended Mounting Screw
Torque : 1 Lbin (0.113 Nm)
ER
Note:
These dimensions include shaft endplay and codewheel warp. All dimension for mounting the module and codewheel should be measured with
respect to two mounting boss, as shown above.
Error
Rop = 11mm
Unit
Notes
EG Gap
± 0.20
mm
Recommend to mount the codewheel closer to the detector side
(upper side) for optimum encoder performance.
ER Radial
± 0.13
mm
ET Tangential
± 0.13
mm
7
Package Dimension
Optical Center Axis
17.80
21.60
R15.50
3.00
1.60
4.40
Optical Center Axis
2.69
3.69 Top View
5.34
1.17
Optical Center Axis
13.60
1.27
0.46
3.69
3.00
2.40
13.6
Front View
1.78
4.00
4.90
R0.89
0.80
1.6
Side View
2.00
21.60
TYPICAL DIMENSIONS IN MILLIMETERS
8
Ordering Information
AEDT-9140 Option
Resolution Options
C
E
F
G
H
A
I
B
-
100 CPR
200 CPR
256 CPR
360 CPR
400 CPR
500 CPR
512 CPR
1000 CPR
Codewheels Optical Radius
00 - 11.00 mm
0B - 11.68 mm
For product information and a complete list of distributors, please go to our web site:
www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies in the United States and other countries.
Data subject to change. Copyright © 2005-2009 Avago Technologies. All rights reserved.
AV02-1101EN - November 10, 2009