HEDS-9040/9140
Three Channel Optical Incremental Encoder Modules
Data Sheet
Description
The HEDS-9040 and HEDS-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 detec-
tor IC enclosed in a small plastic package. Due to a highly
collimated light source and a unique photodetector array,
these modules provide the same high performance found
in the HEDS-9000/9100 two channel encoder family.
Features
•
•
•
•
•
•
•
•
•
Two channel quadrature output with index pulse
Resolution up to 2000 CPR (Counts Per Revolution)
Low cost
Easy to mount
No signal adjustment required
Small size
-40°C to 100°C operating temperature
TTL compatible
Single 5 V supply
8.6 (0.34)
2.54 (0.100) TYP.
1.0 (0.04)
DATE CODE
3.73 ± 0.05
(0.147 ± 0.002)
20.8
(0.82)
11.7
(0.46)
2.67 (0.105) DIA.
MOUNTING THRU
HOLE 2 PLACES
2.44/2.41 X 2.79
(0.096/0.095 X 0.110)
2.16 (0.085) DEEP
OPTICAL CENTER
OPTICAL
CENTER LINE
1.78 ± 0.10*
(0.070 ± 0.004)
2.92 ± 0.10**
(0.115 ± 0.004)
10.16
(0.400)
TYPICAL DIMENSIONS IN
MILLIMETERS AND (INCHES)
* GAP MEASUREMENT TO THE SURFACE WINDOW = 1.68
±
0.10 (0.066
±
0.004)
** HEIGHT TO THE WINDOW = 3.02
±
0.10 (0.119
±
0.004)
Package Dimensions
HEDx-9xx0 Option
0.63 (0.025)
SQR. TYP.
OPTION CODE
5.1 (0.20)
26.67 (1.05)
15.2
(0.60)
1.52 (0.060)
V
CC
CH. B
V
CC
CH. A
N.C.
GND
5
4
3
2
1
1.8
(0.07)
2.21
(0.087)
2.9
(0.11)
6.9 (0.27)
GND
2.54
(0.100)
11.9
(0.47)
1.02 ± 0.10
(0.040 ± 0.004)
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095)
2.16 (0.085)
DEEP
1.85 (0.073)
8.64 (0.340)
REF.
17.27
(0.680)
20.96
(0.825)
SIDE A
HEDx-9xx1 Option
0.63 (0.025)
SQR. TYP.
OPTION CODE
5.1 (0.20)
26.67 (1.05)
15.2
(0.60)
2.54 (0.100) TYP.
1.0 (0.04)
DATE CODE
3.73 ± 0.05
(0.147 ± 0.002)
1.02 ± 0.10
(0.040 ± 0.004)
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095)
2.16 (0.085)
DEEP
HEDS-9X01
YYXX
X00
4.01 ± 0.20
(0.158 ± 0.008)
2.9
(0.11)
V
CC
CH. B
V
CC
CH. A
N.C.
GND
1.8
(0.07)
2.21
(0.087)
16.76 ± 0.20
(0.66 ± 0.008)
2.54
(0.100)
11.7
(0.46)
OPTICAL
CENTER LINE
5
4
3
2
1
GND
1.85 (0.073)
8.64 (0.340)
REF.
17.27
(0.680)
20.96
(0.825)
SIDE A
ESD WARNING: NORMAL HANDLING PRECAUTIONS SHOULD BE TAKEN TO AVOID STATIC DISCHARGE.
HEDS-9X00
YYXX
X00
4.75 ± 0.10
(0.187 ± 0.004)
ALIGNING RECESS
2.44/2.41 X 2.79
(0.096/0.095 X 0.110)
2.16 (0.085) DEEP
OPTICAL
CENTER
45
°
5.8
(0.23)
8.81
(0.347)
CL
5.46 ± 0.10
(0.215 ± 0.004)
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095)
2.16 (0.085) DEEP
4.11 (0.162)
6.35 (0.250) REF.
SIDE B
8.6 (0.34)
CL
2.67 (0.105) DIA.
MOUNTING THRU
HOLE 2 PLACES
2.44/2.41 X 2.79
(0.096/0.095 X 0.110)
2.16 (0.085) DEEP
OPTICAL CENTER
4.75 ± 0.10
(0.187 ± 0.004)
ALIGNING RECESS
2.44/2.41 X 2.79
(0.096/0.095 X 0.110)
2.16 (0.085) DEEP
OPTICAL
CENTER
45
°
5.8
(0.23)
8.81
(0.347)
1.78 ± 0.10*
(0.070 ± 0.004)
2.92 ± 0.10**
(0.115 ± 0.004)
10.16
(0.400)
5.46 ± 0.10
(0.215 ± 0.004)
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095)
2.16 (0.085) DEEP
4.11 (0.162)
6.35 (0.250) REF.
TYPICAL DIMENSIONS IN
MILLIMETERS AND (INCHES)
* GAP MEASUREMENT TO THE SURFACE WINDOW = 1.68
±
0.10 (0.066
±
0.004)
** HEIGHT TO THE WINDOW = 3.02
±
0.10 (0.119
±
0.004)
SIDE B
The HEDS-9040 and 9140 have 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 HEDS-9040 is designed for use with a HEDX-614X
codewheel which has an optical radius of 23.36 mm
(0.920 inch). The HEDS-9140 is designed for use with a
HEDx-5x4x codewheel which has an optical radius of
11.00 mm (0.433 inch).
The quadrature signals and the index pulse are accessed
through five 0.025 inch square pins located on 0.1 inch
centers.
Standard resolutions between 256 and 2000 counts per
revolution are available. Consult local Avago sales repre-
sentatives for other resolutions.
Theory of Operation
The HEDS-9040 and 9140 are emitter/detector modules.
Coupled with a codewheel, these modules translate the
rotary motion of a shaft into a three-channel digital out-
put.
As seen in the block diagram, 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 pat-
tern that corresponds to the radius and design of the
codewheel. 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 photo-
diode outputs are then fed through the signal process-
ing circuitry resulting in A, A, B, B, I and I. Comparators
receive these signals and produce the final outputs for
channels A and B. Due to this integrated phasing tech-
nique, the digital output of channel A is in quadrature
with that of channel B (90 degrees out of phase).
The output of the comparator for I and I is sent to the in-
dex processing circuitry along with the outputs of chan-
nels A and B. The final output of channel I is an index
pulse P
O
which is generated once for each full rotation of
the codewheel. This output P
O
is a one state width (nomi-
nally 90 electrical degrees), high true index pulse which
is coincident with the low states of channels A and B.
Applications
The HEDS-9040 and 9140 provide sophisticated motion
control detection at a low cost, making them ideal for
high volume applications. Typical applications include
printers, plotters, tape drives, and industrial and factory
automation equipment.
Note:
Avago Technologies encoders are not recommend-
ed for use in safety critical applications. Eg. ABS braking
systems, power steering, life support systems and critical
care medical equipment. Please contact sales represen-
tative if more clarification is needed.
2
Block Diagram
RESISTOR
V
CC
PHOTO
DIODES
LENS
4
COMPARATORS
A
A
B
B
I
I
SIGNAL PROCESSING
CIRCUITRY
+
−
3
CH. A
LED
+
−
5
CH. B
+
−
INDEX-
PROCESSING
CIRCUITRY
2
CH. I
GND
1
EMITTER
SECTION
CODE
WHEEL
DETECTOR SECTION
Output Waveforms
C
2.4 V
0.4 V
S3
S4
2.4 V
0.4 V
t
1
t
2
2.4 V
0.4 V
P
0
CH. B
P
φ
AMPLITUDE
S1
S2
CH. A
CH. I
ROTATION
3
Definitions
Count (N):
The number of bar and window pairs or counts
per revolution (CPR) of the codewheel.
One Cycle (C):
360 electrical degrees (°e), 1 bar and win-
dow pair.
One Shaft Rotation:
360 mechanical degrees, N cycles.
Position Error (
∆Θ):
The normalized angular difference
between the actual shaft position and the position indi-
cated by the encoder cycle count.
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 in-
crement 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 number of electrical degrees be-
tween 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 (φ):
The number 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.
Direction of Rotation:
When the codewheel rotates in the
direction of the arrow on top of the module, channel A
will lead channel B. If the codewheel rotates in the oppo-
site direction, channel B will lead channel A.
Optical Radius (R
OP
):
The distance from the codewheel’s
center of rotation to the optical center (O.C.) of the en-
coder module.
Index Pulse Width (P
O
):
The number of electrical degrees
that an index is high during one full shaft rotation. This
value is nominally 90°e or 1/4 cycle.
Absolute Maximum Ratings
Storage Temperature, T
S
........................................................................-40°C to +100°C
Operating Temperature, T
A
...................................................................-40°C to +100°C
Supply Voltage, V
CC
.......................................................................................... -0.5 V to 7 V
Output Voltage, V
O
............................................................................................-0.5 V to V
CC
Output Current per Channel, I
OUT
.......................................................-1.0 mA to 5 mA
Shaft Axial Play .............................................................................±0.25 mm (±0.010 in.)
Shaft Eccentricity Plus Radial Play .......................................... 0.1 mm (0.004 in.) TIR
Velocity............................................................................................................. 30,000 RPM
[1]
Acceleration ..........................................................................................250,000 rad/sec
2[1]
Note:
1. Absolute maximums for HEDS-5140/6140 codewheels only.
4
Recommended Operating Conditions
Parameter
Temperature
Supply Voltage
Load Capacitance
Count Frequency
Shaft Perpendicularity
Plus Axial Play
Shaft Eccentricity Plus
Radial Play
Symbol
T
A
V
CC
C
L
f
Min.
-40
4.5
Typ.
5.0
Max.
100
5.5
100
100
±0.25
(±0.010)
0.04
(0.0015)
Units
°C
Volts
pF
kHz
mm
(in.)
mm (in.)
TIR
Notes
Ripple < 100 mV
p-p
2.7 kΩ pull-up
Velocity (rpm) x N/60
6.9 mm (0.27 in.) from
mounting surface
6.9 mm (0.27 in.) from
mounting surface
Note:
The module performance is guaranteed to 100 kHz but can operate at higher frequencies. For the HEDS-9040 #T00 for operation below 0°C
and greater than 50 kHz the maximum Pulse Width and Logic State Width errors are 60°e.
Encoding Characteristics
HEDS-9040 (except #T00), HEDS-9140 (except #B00)
Encoding Characteristics over Recommended Operating Range and Recommended Mounting Tolerances unless
otherwise specified. Values are for the worst error over the full rotation of HEDS-5140 and HEDS-6140 codewheels.
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 fall after
CH. A or CH. B rise
Note:
-25°C to +100°C
-40°C to +100°C
-25°C to +100°C
-40°C to +100°C
Symbol
∆C
∆P
∆S
∆φ
∆Θ
P
O
t
1
t
1
t
2
t
2
Min.
Typ.
[1]
3
7
5
2
10
Max.
5.5
30
30
15
40
120
250
250
300
1000
Units
°e
°e
°e
°e
min. of arc
°e
ns
ns
ns
ns
60
10
-300
70
70
90
100
100
150
150
1. Module mounted on tolerance circle of ±0.13 mm (±0.005 in.) radius referenced from module Side A aligning recess centers. 2.7 kΩ pull-up
resistors used on all encoder module outputs.
5
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