HEDT-9040, HEDT-9140
High Temperature 140°C
Three Channel Optical
Incremental Encoder Modules
Data Sheet
Description
The HEDT-9040 and HEDT-9140 are high temperature
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 provide the
same high performance found in the HEDS-9040/9140
three channel encoders.
The HEDT-9040 and 9140 have Block Diagram two channel
quadrature outputs plus a third channel index output.
This index output is a 90 electrical degree high true index
pulse.
The HEDT-9040 is designed for codewheels which have an
optical radius of 23.36 mm (0.920 in.). The HEDT-9140 is
designed for codewheels which have an optical radius of
11.00 mm (0.433 in.).
The quadrature signals and the index pulse are accessed
through five 0.025 inch square pins located on 0.1 inch
centers.
Resolutions between 360 and 1024 counts per revolution
are available. Consult local Avago sales representatives for
other resolutions.
Features
•
-40°C to 140°C Operating Temperature
•
Two Channel Quadrature Output with Index Pulse
•
Suitable for Automotive Applications
•
Resolution up to 1024 Counts per Revolution
•
Low Cost
•
Easy to Mount
•
No Signal Adjustment Required
•
Small Size
Applications
The HEDT-9040 and 9140 provide high temperature
motion control detection at a low cost, making them
suitable for automotive and industrial applications.
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 representa-
tive if more clarification is needed.
CAUTION:
It is advised that normal static precautions be taken in handling and assembly
of this component to prevent damage and/or degradation which may be induced by ESD.
Package Dimensions
HEDT-9040
0.63 (0.025)
SQR. TYP.
OPTION CODE
5.1 (0.20)
HEDT-9X40
GND
2.54 (0.100) TYP.
1.0 (0.04)
DATE CODE
3.73 ± 0.05
(0.147 ± 0.002)
20.8
(0.82)
1.52 (0.060)
2.21
(0.087) 2.54
(0.100)
11.7
(0.46)
OPTICAL
CENTER LINE
5.46 ± 0.10
(0.215 ± 0.004)
10.16
(0.400)
1.8
(0.07)
2.9
(0.11)
6.9 (0.27)
V
CC
CH. B
V
CC
CH. A
CH. 1
GND
5
4
3
2
1
26.67 (1.05)
15.2
(0.60)
8.6 (0.34)
11.9
(0.47)
8.81
5.8 (0.347)
(0.23)
1.02 ± 0.10
(0.040 ± 0.004)
ALIGNING RECESS
2.44/2.41 DIA.
1.85 (0.073)
(0.096/0.095)
2.16 (0.085)
8.64 (0.340)
DEEP
REF.
YYWW
X00
C
L
17.27
(0.680)
20.96
(0.825)
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 ± 0.01
(0.187 ± 0.004)
45
1.78 ± 0.10
(0.070 ± 0.004)
2.92 ± 0.10
(0.115 ± 0.004)
OPTICAL
CENTER
4.11 (0.162)
6.35 (0.250) REF.
SIDE A
TYPICAL DIMENSIONS IN
MILLIMETERS AND (INCHES)
SIDE B
HEDT-9041
2.54 (0.100) TYP.
1.0 (0.04)
DATE CODE
3.73 ± 0.05
(0.147 ± 0.002)
16.76 ± 0.20
(0.66 ± 0.008)
HEDT-9x41
4.01 ± 0.20
(0.158 ± 0.008)
2.21
(0.087) 2.54
(0.100)
V
CC
5 CH. B
4 V
CC
3 CH. A
2 N.C.
1 GND
0.63 (0.025)
SQR. TYP.
OPTION CODE
5.1 (0.20)
26.67 (1.05)
15.2
(0.60)
8.6 (0.34)
GND
1.8
(0.07)
2.9
(0.11)
1.02 ± 0.10
(0.040 ± 0.004)
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095) 1.85 (0.073)
2.16 (0.085)
8.64 (0.340)
DEEP
REF.
11.7
(0.46)
OPTICAL
CENTER LINE
5.46 ± 0.10
(0.215 ± 0.004)
10.16
(0.400)
YYXX
X00
C
L
17.27
(0.680)
20.96
(0.825)
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°
8.81
5.8 (0.347)
(0.23)
1.78 ± 0.10
(0.070 ± 0.004)
2.92 ± 0.10
(0.115 ± 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 A
TYPICAL DIMENSIONS IN
MILLIMETERS AND (INCHES)
SIDE B
2
Theory of Operation
The HEDT-9040 and 9104 are emitter/detector modules.
Coupled with a codewheel, these modules translate the
rotary motion of a shaft into a threechannel digital output.
As seen in the block diagram, the module contains a single
Light Emitting Diode (LED) as its light source. The light is
collimated into a parallel beam by means of a single 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
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 processing
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 technique, 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
index processing circuitry along with the outputs of
channels A and B. The final output of channel I is an index
pulse Po which is a one state width (nominally 90 electri-
cal degrees), high true index pulse. This pulse is coincident
with the low states of channels A and B.
Block Diagram
RESISTOR
PHOTO
DIODES
LENS
COMPARATORS
A
A
LED
B
B
I
I
SIGNAL PROCESSING
CIRCUITRY
+
−
3
4
V
CC
CH. A
+
−
5
CH. B
+
−
INDEX-
PROCESSING
CIRCUITRY
2
CH. I
GND
1
DETECTOR SECTION
EMITTER
SECTION
CODE
WHEEL
3
Output Waveforms
C
2.4 V
0.4 V
S3
S4
2.4 V
0.4 V
t
2
2.4 V
0.4 V
P
0
P
φ
AMPLITUDE
S1
S2
CH. A
t
1
CH. B
CH. I
ROTATION
Definitions
Count (N):
The number of bar and window pairs or counts
per revolution (CPR) of the codewheel.
State Width Error (ΔS):
The deviation, in electrical degrees,
of each state width from its ideal value of 90°e.
One Cycle (C):
360 electrical degrees (°e), 1 bar and window
pair.
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.
One Shaft Rotation:
360 mechanical degrees, N cycles.
Position Error (ΔΘ):
The normalized angular difference
between the actual shaft position and the position
indicated by the encoder cycle count.
Phase Error (Δφ):
The deviation of the phase from its ideal
value of 90°e.
Cycle Error (ΔC):
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 l/N of a revolution .
Direction of Rotation:
When the codewheel rotates in the
direction of the arrow on top of the module, channel A will
load channel B. If the codewheel rotates in the opposite
direction, channel B will lead channel A.
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.
Optical Radius (R
OP
):
The distance from the codewheel’s
center of rotation to the optical center (O.C.) of the
encoder module.
Pulse Width Error (ΔP):
The deviation, in electrical degrees,
of the pulse width from its ideal value of 180°e.
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.
State Width (S):
The number of electrical degrees between
a transition in the output of channel A and the neighbor-
ing transition in the output of channel B. There are 4 states
per cycle, each nominally 90°e.
4
Absolute Maximum Ratings
Parameter
Storage Temperature
Operating Temperature
Supply Voltage
Output Voltage
Output Current per Channel
Shaft Axial Play
Shaft Eccentricity Plus Radial Play
Velocity
Acceleration
Note:
1. Absolute maximums for HEDS-5140 codewheel only.
Symbol
T
S
T
A
V
CC
V
O
I
OUT
Minimum
-40
-40
-0.5
Typical
Maximum
140
140
7
Units
°C
°C
V
V
-0.5 V to V
CC
-1.0
5
± 0.25
(± 0.010)
0.1
(0 004)
30,000
250,000
mA
mm (in.)
mm (in.)
TIR
RPM
[1]
rad/sec
2[1]
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.
140
5.5
100
50
± 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 50 kHz but can operate at higher frequencies.
Encoding Characteristics
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-514X and HEDS-6145 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
Symbol
ΔC
ΔP
ΔS
Δφ
ΔΘ
P
O
t
1
t
2
Min.
Typ.*
5
7
5
2
10
Max.
10
30
30
15
40
120
1490
620
Units
°e
°e
°e
°e
min. of arc
°e
ns
ns
60
20
40
90
430
250
Note: 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
