AEDT-9140 Series
High Temperature 115qC
Three Channel Optical Incremental Encoder Modules
100 CPR to 1000 CPR
Data Sheet
Description
The AEDT-9140 series are three channel optical incremen-
tal 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.
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.
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.
Features
x
Two channel quadrature output with index pulse
x
Resolution from 100 CPR to 1000 CPR (Cycles Per
Revolution)
x
Low cost
x
Easy to mount
x
No signal adjustment required
x
Small size
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
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.
As seen in Figure 1, the modules contain a single Light
Emitting Diode (LED) as its light source. The light is col-
limated into a parallel beam by means of a single poly-
carbonate 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 process-
ing 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 corre-
sponds 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 I-
bar. 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).
Definitions
Note: Refer to Figure 2
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 differ-
ence 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 (di-
rection 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 cen-
ter 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
RESISTOR
V
CC
LENS
PHOTO
DIODES
COMPARATORS
A
A
LED
B
B
CH. B
CH. A
CH. I
I
I
INDEX
PROCESSING
CIRCUITRY
SIGNAL PROCESSING
CIRCUITRY
EMITTER SECTION
Figure 1.
CODE
WHEEL
DETECTOR SECTION
GND
Output Waveforms
Figure 2.
3
AEDT-9140 Technical Specifications
Absolute Maximum Ratings
Parameter
Storage Temperature
Operating Temperature
Supply Voltage
Output Voltage
Output Current per Channel, Iout
Symbol
T
S
T
A
V
CC
V
O
Min.
-40
-40
-0.5
-0.5
Max.
115
115
7
V
CC
Units
°C
°C
Volts
Volts
Notes
I
OUT
-1.0
18
mA
Recommended Operating Conditions
Parameter
Temperature
Supply Voltage
Load Capacitance
Frequency
Shaft Perpendicularity
Plus Axial Play
Shaft Eccentricity
Plus Radial Play
Symbol
T
A
V
CC
C
L
f
Min.
-40
4.5
Typ.
Max.
115
Units
°C
Volts
pF
kHz
mm
(in.)
mm
(in.)
Notes
5.0
5.5
100
100
r
0.20
(r 0.008)
0.04
(0.0015)
Ripple < 100mVp-p
2.7 kΩ pull-up
Velocity (rpm) x N/60
Refer to Mounting Consideration
Refer to Mounting Consideration
Electrical Characteristics
Electrical characteristics over recommend operating range, typical at 25qC.
Parameter
Supply Current
High Level Output Voltage
Symbol
I
CC
V
OH
V
OL
t
r
t
f
Min.
30
2.4
Typ
57
Max.
85
Units
mA
V
Notes
Typ. I
OH
= -0.5 mA
Typ. I
OL
= 10 mA
C
L
= 25 pF
R
L
= 2.7 k: pull-up
Low Level Output Voltage
Rise Time
Fall Time
0.4
180
50
V
ns
ns
Note: Typical values specified at Vcc = 5.0 V and 25 °C
4
Encoding Characteristics
AEDT-9140 (except – B0B)
Encoding Characteristics over the recommended operating conditions and recommended mounting tolerances unless
otherwise specified.
Parameter
Cycle Error
Pulse Width Error
Logic State Width Error
Phase Error
Position Error
Index Pulse Width
CH I rise after
CH B or CH A fall
CH I rise after
CH A or CH B rise
-40°C to + 115°C
-40°C to + 115°C
Symbol
∆
C
∆
P
∆
S
∆
φ
∆
Θ
P
o
t
1
t
2
Min.
Typ.
3
7
5
2
10
Max.
15
30
30
15
40
120
1000
1000
Units
°e
°e
°e
°e
min. of arc
°e
ns
ns
60
10
10
90
100
300
Encoding Characteristics
AEDT-9140-B0B & AEDT-9140-B00
Encoding characteristics over the recommended operating conditions and recommended mounting tolerances unless
otherwise specified.
Parameter
Cycle Error
- B0B option
- B00 option
Symbol
∆
C
∆
P
∆
S
∆
φ
∆
Θ
P
o
-40°C to + 115°C
t
1
t
2
Min.
Typ.
3
6
7
5
2
10
Max.
15
20
50
50
15
40
120
1500
1500
Units
°e
°e
°e
°e
min. of arc
°e
ns
ns
Pulse Width Error
Logic State Width Error
Phase Error
Position Error
Index Pulse Width
CH I rise after
CH B or CH A fall
40
10
10
90
450
250
CH I rise after
-40°C to + 115°C
CH A or CH B rise
5
