HEDT-9040, HEDT-9140
High Temperature 140°C
Three Channel Optical
Incremental Encoder Modules
Data Sheet
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.
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 ve 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
x -40°C to 140°C Operating Temperature
x Two Channel Quadrature Output with Index Pulse
x Suitable for Industrial Applications
x Resolution up to 1024 Counts per Revolution
x Low Cost
x Easy to Mount
x No Signal Adjustment Required
x Small Size
Applications
The HEDT-9040 and 9140 provide high temperature
motion control detection at a low cost, making them
suitable for 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 clarication is needed.
2
Package Dimensions
HEDT-9040
26.67 (1.05)
HEDT-9X40
15.2
(0.60)
CL
17.27
(0.680)
20.96
(0.825)
1.85 (0.073)
8.64 (0.340)
REF.
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095)
2.16 (0.085)
DEEP
1.02 ± 0.10
(0.040 ± 0.004)
5.1 (0.20)
X00
YYWW
OPTION CODE
0.63 (0.025)
SQR. TYP. 2.54 (0.100) TYP.
DATE CODE
1.0 (0.04)
3.73 ± 0.05
(0.147 ± 0.002)
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
1.52 (0.060)
20.8
(0.82)
11.7
(0.46)
8.6 (0.34)
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)
OPTICAL
CENTER LINE
2.54
(0.100)
2.21
(0.087)
5.8
(0.23)
6.35 (0.250) REF.
4.11 (0.162)
OPTICAL
CENTER
45
8.81
(0.347)
11.9
(0.47)
4.75 ± 0.01
(0.187 ± 0.004)
2.9
(0.11)
1.8
(0.07)
6.9 (0.27)
VCC
GND
5 CH. B
4 VCC
3 CH. A
2 CH. 1
1 GND
SIDE A SIDE B
TYPICAL DIMENSIONS IN
MILLIMETERS AND (INCHES)
26.67 (1.05)
HEDT-9x41
15.2
(0.60)
CL
17.27
(0.680)
20.96
(0.825)
1.85 (0.073)
8.64 (0.340)
REF.
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095)
2.16 (0.085)
DEEP
1.02 ± 0.10
(0.040 ± 0.004)
5.1 (0.20)
X00
YYXX
OPTION CODE
0.63 (0.025)
SQR. TYP. 2.54 (0.100) TYP.
DATE CODE
1.0 (0.04)
3.73 ± 0.05
(0.147 ± 0.002)
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
11.7
(0.46)
8.6 (0.34)
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)
OPTICAL
CENTER LINE
2.54
(0.100)
2.21
(0.087)
5.8
(0.23)
6.35 (0.250) REF.
ALIGNING RECESS
2.44/2.41 X 2.79
(0.096/0.095 X 0.110)
2.16 (0.085) DEEP
4.11 (0.162)
ALIGNING RECESS
2.44/2.41 DIA.
(0.096/0.095)
2.16 (0.085) DEEP
OPTICAL
CENTER
45°
8.81
(0.347)
4.75 ± 0.10
(0.187 ± 0.004)
2.9
(0.11)
1.8
(0.07)
VCC
GND
5 CH. B
4 VCC
3 CH. A
2 N.C.
1 GND
SIDE A SIDE B
TYPICAL DIMENSIONS IN
MILLIMETERS AND (INCHES)
4.01 ± 0.20
(0.158 ± 0.008)
16.76 ± 0.20
(0.66 ± 0.008)
HEDT-9041
3
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
Block Diagram
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 nal 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 nal 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.
PHOTO
DIODESCOMPARATORS
INDEX-
PROCESSING
CIRCUITRY
SIGNAL PROCESSING
CIRCUITRY
DETECTOR SECTION
CODE
WHEEL
EMITTER
SECTION
LENS
LED
VCC
CH. A
CH. B
CH. I
GND
RESISTOR
+
−
A
A
+
−
B
B
+
−
I
I
4
3
5
2
1
4
Output Waveforms
Denitions
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 window
pair.
One Shaft Rotation: 360 mechanical degrees, N cycles.
Position Error ('4): The normalized angular dierence
between the actual shaft position and the position
indicated 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 increment
of l/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 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.
State Width Error ('S): The deviation, in electrical degrees,
of each state width from its ideal value of 90°e.
Phase (I): 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 ('I): 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
load 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 90°e or 1/4 cycle.
P
C
CH. A
CH. B
ROTATION
AMPLITUDE
φ
S1S2 S3 S4
CH. I
2.4 V
0.4 V
2.4 V
0.4 V
2.4 V
0.4 V
P0
t1t2
5
Absolute Maximum Ratings
Parameter Symbol Minimum Typical Maximum Units
Storage Temperature TS-40 140 °C
Operating Temperature TA-40 140 °C
Supply Voltage VCC -0.5 7 V
Output Voltage VO-0.5 V to VCC V
Output Current per Channel IOUT -1.0 5 mA
Shaft Axial Play ± 0.25
(± 0.010)
mm (in.)
Shaft Eccentricity Plus Radial Play 0.1
(0 004)
mm (in.)
TIR
Velocity 30,000 RPM[1]
Acceleration 250,000 rad/sec2[1]
Note:
1. Absolute maximums for HEDS-5140 codewheel only.
Recommended Operating Conditions
Parameter Symbol Min. Typ. Max. Units Notes
Temperature TA -40 140 °C
Supply Voltage VCC 4.5 5.0 5.5 Volts Ripple < 100 mVp-p
Load Capacitance CL 100 pF 2.7 k: pull-up
Count Frequency f 50 kHz Velocity (rpm) x N/60
Shaft Perpendicularity Plus Axial Play ± 0.25
(± 0.010)
mm (in.) 6.9 mm (0.27 in.) from
mounting surface
Shaft Eccentricity Plus Radial Play 0.04
(0.0015)
mm (in.)
TIR
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 specied. Values are for the worst error over the full rotation of HEDS-514X and HEDS-6145 codewheels.
Parameter Symbol Min. Typ.* Max. Units
Cycle Error 'C 5 10 °e
Pulse Width Error 'P 7 30 °e
Logic State Width Error 'S 5 30 °e
Phase Error 'I 2 15 °e
Position Error '4 10 40 min. of arc
Index Pulse Width PO 60 90 120 °e
CH. I rise after CH. B or CH. A fall t1 20 430 1490 ns
CH. I fall after CH. A or CH. B rise t2 40 250 620 ns
Note: Module mounted on tolerance circle of ± 0.13 mm (± 0.005 in.) radius referenced from module Side A aligning recess centers. 2.7 k: pull-up
resistors used on all encoder module outputs.
6
Electrical Characteristics
Electrical Characteristics over Recommended Operating Range.
Parameter Symbol Min. Typ.* Max. Units Notes
Supply Current ICC 30 57 85 mA
High Level Output Voltage VOH 2.4 V IOH = -100 mA min.
Low Level Output Voltage VOL 0.4 V IOL = 3.86 mA max.
Rise Time tr 90 ns CL = 25 pF
Fall Time tf 80 ns
RL = 2.7 k: pull-up
*Typical values specied at VCC = 5.0 V and 25°C.
Mechanical Characteristics
Part No. Parameter Dimension Tolerance Units
HEDS-5140 11.00 mm
optical radius codewheel
Codewheel Available to
Fit These Standard Shaft Diameters
2 3 4
5 6 8
+0.000
-0.015
mm
5/32 1/8
3/16 1/4
+0.000
-0.0007
in.
Moment of Inertia 0.6 (8.0 x 10-6)g-cm
2 (oz-in-s2)
Note: The tolerance requirements are on the mating shaft, not on the codewheel.
Electrical Interface
To insure reliable encoding performance, the HEDT-9040
and 9140 three channel encoder modules require 2.7
kW (± 10%) pull-up resistors on output pins 2, 3, and 5
(Channels I, A, and B) as shown in Figure 1. These pull-up
resistors should be located in close proximity of the
encoder module (within 4 feet). Each of the three encoder
module outputs can drive a single TTL load in this con-
guration.
Mounting Considerations
Figure 2 shows a mounting tolerance requirement for
proper operation of the HEDT-9040 and HEDT-9140. The
Aligning Recess Centers must be located within a tolerance
circle of 0.13 mm (0.005 in.) radius from the nominal
locations. This tolerance must be maintained whether the
module is mounted with Side A as the mounting plane
using aligning pins (see Figure 5), or mounted with Side
B as the mounting plane using an alignment tool (see
Figures 3 and 4).
Figure 1. Pull-up Resistors on HEDT-9X40 Encoder Module Outputs.
Figure 2. HEDT-9X40 Mounting Tolerance.
7
Mounting the HEDT-9140 with an Alignment Tool
The HEDS-8905 alignment tool is recommended for
mounting the HEDT-9140 module with Side B as the
mounting plane. This tool can only be used when the HEDT-
9140 module is mounted with the HEDS-5140 (codewheel
with hub). The HEDS-8905 tool xes the module position
using the codewheel hub as a reference. It will not work if
Side A is used as the mounting plane.
The following assembly procedure uses the HEDS-8905
alignment tool to mount an HEDT-9140 module and an
HEDS-5140 codewheel:
Instructions:
1. Place codewheel on shaft.
2. Set codewheel height: (a) place alignment tool on
motor base (pins facing up) ush up against the motor
shaft as shown in Figure 3. (b) Push codewheel down
against alignment tool. The codewheel is now at the
proper height. (c) Tighten codewheel setscrew and
remove alignment tool.
Some motors have a boss around the shaft that
extends above the mounting plane. In this case, the
alignment tool cannot be used as a gage block to set
the codewheel height as described in 2(a), (b), and (c).
If boss is above mounting plane: Slide module onto
motor base, adjusting height of codewheel so that it
sits approximately in the middle of module slot. Lightly
tighten setscrew. The codewheel height will be more
precisely set in step 5.
3. Insert mounting screws through module and thread
into the motor base. Do not tighten screws.
4. Slide alignment tool over codewheel hub and onto
module as shown in Figure 4. The pins of the alignment
tool should t snugly inside the alignment recesses of
the module.
If boss is above mounting plane: The pins of the tool may
not mate properly because the codewheel is too high
on the shaft. Loosen codewheel setscrew and lower
codewheel slightly. Retighten setscrew lightly and
attempt this step again.
5. While holding alignment tool in place, tighten screws
down to secure module.
If boss is above mounting plane: Push codewheel up
ush against alignment tool to set codewheel height.
Tighten codewheel setscrew.
6. Remove alignment tool.
Figure 3. Alignment Tool is Used to Set Height of Codewheel. Figure 4. Alignment Tool is Placed over Shaft and onto Codewheel Hub.
Alignment Tool Pins Mate with Aligning Recesses on Module.
8
Mounting with Aligning Pins
The HEDT-9040 and HEDT-9140 can also be mounted using aligning pins on the mounting surface. (Avago does not
provide aligning pins.) For this conguration, Side A must be used as the mounting plane. The aligning recess centers
must be located within the 0.13 mm (0.005 in.) Radius Tolerance Circle as explained in “Mounting Considerations.”
Figure 5 shows the necessary dimensions.
Figure 5. Mounting Plane Side A.
Figure 6. HEDS-5140 Codewheel Used with HEDT-9140.
9
Ordering Information
Three Channel Encoder Modules and Codewheels, 11.00 mm Optical Radius
Resolution
(Cycles/Rev)
I = 512 CPR
Shaft Diameter
00 - WITHOUT HUB
01 - 2 mm 11 - 4 mm
02 - 3 mm 14 - 5 mm
03 - 1/8 in. 12 - 6 mm
04 - 5/32 in. 13 - 8 mm
06 - 1/4 in.
Hub
0 - Codewheel w/Hub
5 - Codewheel w/o Hub
HEDT-914 Option HEDS-514 Option 00
LEAD
0-STRAIGHT LEADS
1-BENT LEADS
A E F G I
*
*
01 02 03 04 05 06 08 09 10 11 12 13 14
I * * * * * * *
HEDT-9140
HEDT-9141
HEDS-5140
Accessories
HEDS-8905
Alignment Tool for mounting the HEDT-9140.
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 © 2005-2011 Avago Technologies. All rights reserved.
AV02-1932EN - January 12, 2011
Using Multiple Index Pulses
The third channel index (Channel I) is not limited to
occurring just once per revolution. Index pulses may be
placed arbitrarily over a full codewheel rotation. This is
done by altering only the pattern of the codewheel with
no modications necessary to the HEDT-9X40 module.
The only restriction is that, depending on the CPR of the
codewheel, consecutive index pulses may have to be
separated by at least 10 full cycles.
Multiple index pulses can provide more precise absolute
position information. By strategically placing the index
pulses, a unique index series can be created for a par-
ticular angular position. This leads to the idea of the
“quasiabsolute” encoder in which only a partial turning
of the codewheel is required to determine the absolute
position.
A special codewheel is required to accomplish a multiple
index pattern. The standard HEDS-5140, 5145, and 6145
codewheels have one index pulse per full revolution.
Please consult a local Avago sales representative for
further information.