Description
The HEDS-65xx/HEDL-65xx are high performance
two and three channel optical incremental encoders.
These encoders emphasize high reliability, high
resolution, and easy assembly. Each encoder contains a
lensed LED source (emitter), an integrated circuit with
detectors and output circuitry, and a codewheel which
rotates between the emitter and detector integrated
circuit. The outputs of the HEDS-6500 are two single
ended square waves in quadrature. The HEDL-65xx
outputs are dierential.
The HEDS-6540 / HEDL-6540 also have a third channel
index output in addition to the two quadrature outputs.
This index is an active high pulse that occurs once ev-
ery full rotation of the codewheel. Resolutions up to 1024
Counts Per Revolution are available in the two and three
channel versions.
The line driver option oers enhanced performance
when the encoder is used in noisy environments, or
when it is required to drive long distances.
The line driver option utilizes an industry standard line
driver IC AM26C31Q which provides complementary
outputs for each encoder channel. Thus the outputs
of the line driver encoder are A and –
A, B and –B, and I and
–
I for three channel versions. Suggested line receivers
are 26C32 and 26C33.
The quadrature signals are accessed through a cable
and 10-pin female connector. Please refer to the or-
dering information at the end of this data sheet for a
selection matrix.
HEDL-65XX fig 1
Applications
The HEDS-65xx / HEDL-65xx provide motion de-
tection to a very high resolution and accept a
variety of shaft sizes up to a maximum of 5/8 inches.
Typical applications include printers, plotters, tape
drives, positioning tables, and automatic handlers.
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 clarication is needed.
Features
• Two channel quadrature output with optional
index pulse
• TTL compatible single ended outputs on HEDS Series
• 100ºC operating temperature for metal code wheel
• 70°C operating temperature for mylar code wheel
• Industry standard AM26C31Q CMOS line driver IC on
HEDL Series
• Easy assembly, no signal adjustment necessary
• Resolutions up to 2048 counts per revolution
HEDL-65xx, HEDM-65xx, HEDS-65xx Series
Large Diameter (56 mm), Housed Two and
Three Channel Optical Encoders
Data Sheet
2
HEDS-65XX #xxx
YYMM
COUNTRY OF ORIGIN
24.0 ± 0.5
(192.2)
0.81
(20.4)
HEDL-65XX fig 2
17.27
(0.680)
24.38
(0.960)
55.88
(2.200)
∅
3.3
(0.128)
∅
2.44
(0.096)
∅
2.44
(0.096)
∅
0.254
(0.010)
25.91
(1.020)
∅
ON ∅ 46.0 B.C.
(∅ 1.811 B.C.)
HEDL-54XX fig 3
SLOTTED
DIMENSIONS IN MILLIMETERS AND (INCHES).
Assembled Unit
Base Plate
Top Cover (Housing)
HEDS-65XX #xxx
YYMM
COUNTRY OF ORIGIN
24.9
(0.98)
5.2
(0.21)
HEDL-65XX fig 4
30.2
(1.19)
65.9
(2.59)
13.2
(0.52)
∅
55.9
(2.20)
∅
DIMENSIONS IN MILLIMETERS AND (INCHES).
3
HEDL-65XX fig 5a
PHOTO DIODES
COMPARATORS
INDEX-PROCESSING
CIRCUITRY
SIGNAL PROCESSING
CIRCUITRY
DETECTOR SECTIONCODE
WHEEL
EMITTER
SECTION
PCB/CABLE/CONNECTOR
LENS
LED
1) CHANNEL A
2) V
CC
3) GND
4) NC
5) NC
6) GROUND
7) V
CC
8) CHANNEL B
9) V
CC
10) CHANNEL I
Pinout A
Pinout A
HEDS-65xx CONNECTOR
PIN OUT
1 Channel A
2 VCC
3 GND
4 NC
5 NC
6 GND
7 VCC
8 Channel B
9 VCC
10 Channel I
Pinout B
HEDL-65xx CONNECTOR
PIN OUT
1 NC
2 VCC
3 GND
4 NC
5 A
6 A
7 B
8 B
9 I (INDEX)
10 I (INDEX)
Connector Pin-out
1
2
9
10
HEDL-65XX fig 6
HEDS-65XX CONNECTOR
PINOUT
HEDL-65XX CONNECTOR
PINOUT
1 CHANNEL A
2 V
CC
3 GND
4 NC
5 NC
6 GND
7 V
CC
8 CHANNEL B
9 V
CC
10 CHANNEL I
1 NC
2 V
CC
3 GND
4 NC
5 A
6 A
7 B
8 B
9 I (INDEX)
10 I (INDEX)
There are two dierent connector pin-out congurations used with the HEDS-65xx / HEDL-65xx series of encoders.
The table below relates the part to its connector pin-out.
HEDL-65XX fig 5b
PHOTO DIODES
COMPARATORS
INDEX-PROCESSING
CIRCUITRY
SIGNAL PROCESSING
CIRCUITRY
DETECTOR SECTIONCODE
WHEEL
EMITTER
SECTION
PCB/CABLE/CONNECTOR
LENS
LED
1) NC
2) VCC
3) GND
4) NC
5) A
6) A
7) B
8) B
9) INDEX
10) INDEX
LINE
DRIVER
Pinout B
4
Theory of Operation
The HEDS-65xx / HEDL-65xx translate the rotary motion
of a shaft into either a two or three channel digital
output.
The HEDS-65xx uses one of the standard HEDS-9000
or HEDS-9040 modules for encoding purposes. The
HEDL-654x uses the standard HEDL-9040 for encoding
purposes.
As seen in the block diagram, these modules contain a
single Light Emitting Diode (LED) as their light source
(emitter). The light is collimated into a single parallel
beam by means of a plastic lens located directly over
the LED. Opposite the emitter is the integrated detector
circuit (detector). This circuit 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 a
pattern of spaces and bars on the codewheel. The pho-
todiodes 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
photodiode outputs are then fed into the signal pro-
cessing circuitry resulting in A, –
A, B, and B (I and –
I also in
the three channel encoders). 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).
In the HEDS-6540 / HEDL-6540 the output of the com-
parator for the index pulse is combined with that of the
outputs of channel A and channel B to produce the nal
index pulse. The index pulse is generated once every
rotation of the codewheel and is a one state width
(nominally 90 electrical degrees), true high index pulse.
It is coincident with the low states on channels A and B.
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 (∆Θ): 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
dierence 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 (P): The number of electrical degrees that an
output is high during one 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 (Φ): the number of electrical degrees between the
center of high state on channel A and the center of the
high state on 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
a counterclockwise direction (when viewed from the
encoder end of the motor) channel A will lead channel B.
If the codewheel rotates in the clockwise direction
channel B will lead channel A.
Index Pulse Width (P0): The number of electrical degrees
that an index output is high during one full shaft rotation.
This value is nominally 90 e or 1/4 cycle.
5
C
S1 S2 S3 S4
PHASE
P
P0
I1 I2
2.4 V
0.4 V
2.4 V
0.4 V
2.4 V
0.4 V
CH A
OUTPUT
CH B
OUTPUT
CH I
OUTPUT
ROTATION
HEDL-65XX fig 7
Waveforms for Encoders without Line Drivers.
Output Waveforms
Waveforms for Encoders with Line Drivers.
6
Recommended Operating Conditions
Parameter HEDS-6500 HEDS-6540 HEDL-6540 HEDL-6545
Temperature -40 to +100 -40 to +100 -40 to +100 -40 to +100 Celsius
Supply Voltage 4.5 to 5.5 4.5 to 5.5 4.5 to 5.5 4.5 to 5.5 Volts
Load Capacitance 100 100 100 100 pF
Count Frequency 100 100 100 100 kHz
Shaft Eccentricity ±.05 ±.05 ±.05 ±.05 mm
Plus Radial Play (±.002) (±.002) (±.002) (±.002) (Inch/1000)
Note: The HEDS-65XX performance is guaranteed to 100 kHz but can operate at higher frequencies. For frequencies above 100 kHz
it is recommended that the load capacitance not exceed 25 pF and pull up resistors of 3.3 kΩ between the output channels and Vcc
are included.
Absolute Maximum Ratings
Parameter HEDS-6500 HEDS-6540 HEDL-6540 HEDL-6545
Storage Temperature -40 to +100 -40 to +100 -40 to +100 -40 to +100 Celsius
Operating Temperature -40 to +100 -40 to +100 -40 to +100 -40 to +100 Celsius
Supply Voltage -.5 to +7 -.5 to +7 -.5 to +7 -.5 to +7 Volts
Output Voltage -.6 to Vcc -.6 to Vcc -.6 to Vcc -.6 to Vcc Volts
Output Current Per Channel -1 to 5 -1 to 5 mA
Velocity 30,000 30,000 30,000 30,000 RPM
Vibration 20 20 20 20 Gs
Shaft Axial Play 5 5 5 5 Inch/1000
Radial Play & Eccentricity 2 2 2 2 Inch/1000
7
Encoding Characteristics
Encoding Characteristics over Recommended Operating Range and Recommended Mounting Tolerances unless
otherwise specied. Values are for the worst error in the full rotation.
Part Number Description Symbol Min. Typ.* Max. Units
HEDS-6500*** Pulse Width Error ∆P 5 35 °e
Logic State Width Error ∆S 5 35 °e
Phase Error ∆Φ 2 15 °e
Position Error ∆Θ 7 20 min. of arc
Cycle Error ∆C 5 5.5 °e
HEDS-6540** Pulse Width Error ∆P 5 35 °e
Logic State Width Error ∆S 5 35 °e
Phase Error ∆Φ 2 15 °e
Position Error ∆Θ 7 20 min. of arc
Cycle Error ∆C 5 5.5 °e
Index Pulse Width ∆P0 55 90 125 °e
CH I fall after CH B or CH A fall
-25°C to +100°C t1 10 100 250 ns
-40°C to +100°C t1 -300 100 250 ns
CH I rise after CH B or CH A rise
-25°C to +100°C t2 70 150 300 ns
-40°C to +100°C t2 70 150 1000 ns
HEDL-654x Pulse Width Error ∆P 5 35 °e
Logic State Width Error ∆S 5 35 °e
Phase Error ∆Φ 2 15 °e
Position Error ∆Θ 7 20 min. of arc
Cycle Error ∆C 5 5.5 °e
Index Pulse Width ∆P0 90 °e
*Typical values specied at Vcc = 5.0 V and 25°C.
**HEDS-6540 – Active high Index part. Pull-up of 2.7 kΩ used on all outputs of modules that do not have a line driver.
***HEDS-6500 – 3.3 kΩ pull-up resistors used on all encoder module outputs.
8
Electrical Characteristics
Electrical Characteristics over Recommended Operating Range, typical at 25°C.
Part Number Symbol* Min. Typ. Max. Units Notes
HEDS-6500 Icc 17 40 mA
VOH 2.4 V IOH = -40 µA max
VOL 0.4 V IOL = 3.2 mA
tr 200 ns CL = 25 pF, RL = 11 kΩ pull-up.
tf 50 ns
HEDS-6540 Icc 30 57 85 mA
VOH 2.4 V IOH = -200 µA max
VOL 0.4 V IOL = 3.86 mA
tr 180 ns CL = 25 pF, RL = 3.3 kΩ pull-up.
tf 40 ns
*Explanation for symbols.
Icc – Supply current, VOH – High Level Output Voltage, VOL – Low Level Output Voltage, tr – Rise Time, tf – Fall Time.
Electrical Interfaces
To insure reliable encoding performance, the HEDS-6540 three channel encoder requires 2.7 kΩ pull-up resistors to
the supply voltage on each of the three output lines Ch. A, Ch. B, and Ch. I located as close as possible to the encoder
Parameter Symbol Dimensions Tolerances [1] Units
Moment Of Inertia J 7.7 (110 x 10-6) gcm2 (oz-in-s2)
Required Shaft Length [2] 15.9 (0.625) ±0.6 (.024) mm (inches)
Bolt Circle [3] 46.0 (1.811) ±0.13 (.005) mm (inches)
Mounting Screw Size [4] 2.5 x 0.45 x 5 mm
Pan Head Style #2-56 x 3/16 Inches
Encoder Base Plate Thickness 3.04 (120) mm (inches)
Mounting Screw Torque 1.0 (0.88) Kg (in-lbs)
Hub Set Screw UNC #2-56 Hex head set screw
Notes:
1. These are tolerances required of the user.
2. Through hole in the encoder housing are also available, for longer shafts.
3. The HEDL-65X0 must be aligned using the aligning pins as specied in the section on “MOUNTING CONSIDERATIONS.”
4. The recommended mounting screw torque for 2 screws is 1.0 Kg (0.88 in-lbs).
Mechanical Characteristics
9
17.27
(0.680)
24.38
(0.960)
—A—
MOTOR SHAFT CENTER
ALIGNING PINS
2.39/2.34 DIA. – 0.76 HIGH
(0.094/0.092–0.030)
0.25 (0.010) x
45° CHAMFER
2 PLACES
∅ 0.15 (0.006) A
15.88
(0.625)
2.62
(0.103)
ALIGNMENT BOSS
∅ 26.010/25.984
(∅ 1.024/1.023)
5.7 (0.225) TALL MAX.
∅ 0.15 (0.006) A
2 SCREW MOUNTING
M2.5 (2-56 UNC-2B)
2 PLCS – EQUALLY
SPACED ON
46.00 (1.811) DIA.
BOLT CIRCLE
∅ 0.25 (0.010) A
HEDL-65XX fig 9
TYPICAL DIMENSIONS IN MILLIMETERS AND (INCHES).
Mounting Considerations
The HEDS-654x/HEDL-654x must be aligned with respect to the optical center (codewheel shaft) as indicated in the
following gure.
The following gure shows how the main encoder components are organized.
If neither locating pins nor locating boss are available, then a centering tool supplied by Avago can be used (HEDS-
6510).
Encoder Mounting and Assembly
HEDL-65XX fig 10
EXPLODED VIEW
10
2
1
HEDL-65XX fig 11
ASSEMBLE COMPONENTS AND MOUNTING
SCREWS AND TOOLS AS APPROPRIATE.
ALIGNMENT
TOOL
HEDL-65XX fig 12
LOAD ENCODER BASEPLATE ONTO
RECEIVING SURFACE (MOTOR END
PLATE) WITH MOUNTING SCREW HOLES
ALIGNED WITH MATING HOLES. LOAD
MOUNTING SCREWS AND LEAVE SLIGHTLY
LOOSE.
11
4
3
HEDL-65XX fig 13
LOCATE ENCODER BASEPLATE
CHOOSE CENTERING CYLINDER OR UNDERSIDE LOCATING PINS.
CENTERING CYLINDER: LOCATE ENCODER BASEPLATE WITH
CENTERING CYLINDER. WHEN IN PLACE, TIGHTEN MOUNTING SCREWS.
LOCATING PINS: WITH LOCATING PINS PROPERLY SEATED IN
CORRESPONDING RECEIVING HOLES IN ENCODER BASEPLATE,
TIGHTEN MOUNTING SCREWS.
HEDL-65XX fig 14
LOCATE ENCODER MODULE AND CODEWHEEL
ALIGN ENCODER MODULE AND CODEWHEEL AS SHOWN.
BE CAREFUL NOT TO DAMAGE THE ENCODER INTERNAL COMPONENTS
WITH THE CODEWHEEL.
BRING THE ENCODER MODULE AND CODEWHEEL DOWN SUCH THAT
THE ENCODER MODULE LOCATING HOLES (ON ITS UNDERSIDE)
MATE WITH THE BASEPLATE ROUND PINS. THE BASEPLATE SQUARE
PINS SHOULD SEAT INTO THE ENCODER MODULE MOUNTING
THRU HOLES.
CONCURRENTLY, BRING THE CODEWHEEL DOWN ONTO THE
MATING SHAFT.
12
5
6
HEDL-65XX fig 15
ALLEN WRENCH TO TIGHTEN CODEWHEEL SET SCREW
CODEWHEEL GAPPING TOOL
WITH CODEWHEEL AND ENCODER MODULE IN PLACE,
PLACE CODEWHEEL GAPPING TOOL UNDER CODEWHEEL
AS SHOWN. INSERT THE ALLEN WRENCH INTO THE
CODEWHEEL SET SCREW AND TIGHTEN. REMOVE ALLEN
WRENCH AND GAPPING TOOL.
HEDL-65XX fig 16
WITH CODEWHEEL AND ENCODER MODULE IN PLACE,
LOAD ENCODER HOUSING FROM TOP INTO "SNAPPED"
POSITION. INSURE THAT ANY CABLES FROM THE
ENCODER MODULE ARE FOLDED DOWN SUCH THAT
THEY EMERGE FROM THE BOTTOM OF THE HOUSING'S
REAR RECTANGULAR PORT.
HEDM – 65
Encoders Film Codewheel (up to 70°C)
OPTION
RESOLUTION
(CYCLES/REV)
T – 2000
U – 2048 2 CH only
SHAFT
DIAMETER
05 – 3/16 in.
06 – 1/4 in.
08 – 3/8 in.
09 – 1/2 in.
10 – 5/8 in.
11 – 4 mm
12 – 6 mm
13 – 8 mm
OUTPUTS
0 – 2 CH
4 – 3 CH
THROUGH
HOLE
0 – None
5 – 13.3 mm
(0.525 in)
HEDS - 65
OPTION
Ordering Information for 2CH and 3CH Encoder Modules
Encoders Metal Codewheel (up to 100°C)
OUTPUTS
0 – 2 CH
4 – 3 CH
THROUGH HOLE
0 – None
5 – 13.3 mm
(0.525 in.)
SHAFT
DIAMETER
05 – 3/16 in.
06 – 1/4 in.
08 – 3/8 in.
09 – 1/2 in.
10 – 5/8 in.
11 – 4 mm
12 – 6 mm
13 – 8 mm
RESOLUTION
(CYCLES/REV)
A = 500
B = 1000
J = 1024
05 06 08 09 10 11 12 13
HEDS-6500# A * * * * * * * *
B * * * * * * * *
J * * * * * * * *
HEDS-6505# A
B * *
J *
HEDS-6540# A * * * * * * * *
B * * * * * * * *
J * * * * * * * *
HEDS-6545# A * *
B *
J * *
05 06 08 09 10 11 12 13
HEDM-6500# T * *
U * *
HEDM-6505# T * *
U *
HEDM-6540# T * *
HEDM-6545# T
14
Ordering Information for HEDS-65XX Codewheel
Gapping Tool
HEDS-6511
HEDL - 65
OPTION
Ordering Information for 2CH and 3CH Encoder Modules with Line Driver
Encoders with Metal Codewheel (up to 100°C)
SHAFT
DIAMETER
08 – 3/8 in.
09 – 1/2 in.
10 – 5/8 in.
11 – 4 mm
12 – 6 mm
13 – 8 mm
RESOLUTION
(CYCLES/REV)
A = 500
B = 1000
J = 1024
OUTPUTS
0 – 2 CH
4 – 3 CH
THROUGH HOLE
0 – None
5 – 13.3 mm
(0.525 in.)
05 06 08 09 10 11 12 13
HEDL-6540# B * *
HEDL-6545# B *
J * * *
HEDS-6510 Option 0
Ordering Information for HEDS=76XX Centering Tools
05 06 08 09 10 11 12 13
HEDS-6510 0 * * * * * * * *
SHAFT
DIAMETER
05 – 3/16 in.
06 – 1/4 in.
08 – 3/8 in.
09 – 1/2 in.
10 – 5/8 in.
11 – 4 mm
12 – 6 mm
13 – 8 mm
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Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies Limited in the United States and other countries.
Data subject to change. Copyright © 2008 Avago Technologies Limited. All rights reserved. Obsoletes 5988-9398EN
AV02-0991EN January 30, 2008