2-127
MOTION SENSING
AND CONTROL
H
Two and Three Channel
Codewheels for use with HP
Optical Encoder Modules
Technical Data
Features:
• Codewheels Available in
Glass, Film, and Metal
• Available in Two Standard
Diameters
• Cost Effective
• Resolutions from 96 CPR to
2048 CPR
• For Use with HEDS-90XX/
91XX Series Two and Three
Channel Encoders
Description
Hewlett-Packard offers a wide
variety of codewheels for use
with Hewlett-Packard’s HEDS-
9000, HEDS-9100, HEDS-9040,
and HEDS-9140 series Encoder
Modules. Designed for many
environments, applications, and
budgets, HP codewheels are
available in Glass, Film, and
Metal. These codewheels are
available in resolutions from 96
Counts Per Revolution (CPR) to
1024 CPR on an 11 mm optical
radius and 500 to 2048 CPR on a
23.36 mm optical radius.
Each of the three codewheel
materials offers a certain
advantage. Metal codewheels are
the most versatile, with a tem-
perature rating up to 100°C,
resolution to 512 CPR (28 mm
diameter), as well as 2 and 3
channel outputs. Film codewheels
offer higher resolution (up to
1024 CPR on a 28 mm diameter)
with an operating temperature of
70°C. Glass codewheels combine
the best of film and metal, offer-
ing a temperature rating of 100°C
and resolutions to 1024 CPR on a
28 mm diameter.
In addition, each material offers a
specific reliability rating. It is
important to consider the specific
application operating environ-
ment, long term operating
conditions, and temperature
ranges when choosing a code-
wheel material.
Also See:
• HEDS-9000/HEDS-9100
Encoder Module Data Sheet
• HEDS-9000/9100/9200
Extended Resolution Encoder
Module Data Sheet
• HEDS-9040/9140 Three
Channel Encoder Module Data
Sheet
• HEDS-9700 Small Encoder
Module Data Sheet
HEDS-51X0/61X0 Series
HEDG-512X/612X Series
HEDM-512X/61XX Series
5965-5891E
2-128
HEDS-XXXX HEDM-XXXX HEDG-XXXX
Parameter Symbol Metal Codewheels Film Codewheels Glass Codewheels
Storage TS-40°C to +100°C -40°C to +70°C -40°C to +100°C
Temperature
Operating TA-40°C to +100°C -40°C to +70°C -40°C to +100°C
Temperature
Humidity non condensing
Velocity 30,000 RPM 30,000 RPM 12,000 RPM
Shaft Axial Play ±0.25 mm ±0.175 mm ±0.175 mm
(±0.010 in) (±0.007 in) (±0.007 in)
Shaft Eccentricity ±0.1 mm ±0.04 mm ±0.04 mm
Plus Radial Play (±0.004 in) TIR (±0.0015 in) TIR (±0.0015 in) TIR
Acceleration 250,000 Rad/Sec2250,000 Rad/Sec2100,000 Rad/Sec2
Absolute Maximum
Ratings
It is important to consider the
environment in which the
codewheels will be used when
selecting a codewheel material. In
brief, metal codewheels are
rugged, but do not offer higher
resolution capabilities. Film
codewheels allow higher
resolution, but cannot endure the
same temperatures and high
humidity as metal. Glass
codewheels offer both high
temperature and higher
resolution, but are also more
expensive. Consider the following
rating table when choosing a
codewheel material.
Recommended Operating Conditions
HEDS-XXXX HEDM-XXXX HEDG-XXXX
Parameter Metal Codewheels Film Codewheels Glass Codewheels
Maximum Count Frequency 100 kHz 200 kHz* 200 kHz
Shaft Perpendicularity ±0.25 mm ±0.175 mm ±0.175 mm
Plus Axial Play (±0.010 in) (±0.007 in) (±0.007 in)
Shaft Eccentricity Plus ±0.1 mm ±0.04 mm ±0.04 mm
Radial Play (±0.004 in) TIR (±0.0015 in) TIR (±0.0015 in) TIR
Note: HP Encoder Modules are guaranteed to 100 kHz, but can operate at higher frequencies. See Encoder Module Data Sheet for
specifications and output load recommendations.
*HEDM-6140 is guaranteed to 100 kHz with the HEDS-9040 #T00 module.
2-129
MOTION SENSING
AND CONTROL
Encoding Characteristics
Encoding characteristics over
recommended operating range
and recommended mounting
Part Number Description Symbol Min. Typ. Max. Units
HEDS-51XX Cycle Error C 3 5.5 °e
Position Error ∆θ 10 40 min. of arc
HEDS-61XX Cycle Error C 3 5.5 °e
Position Error ∆θ 7 20 min. of arc
HEDM-512X Cycle Error C 3 7.5 °e
Position Error ∆θ 4 40 min. of arc
HEDM-61XX Cycle Error C 3 7.5 °e
Position Error ∆θ 2 20 min. of arc
HEDG-512X Cycle Error C 3 7.5 °e
Position Error ∆θ 4 30 min. of arc
HEDG-612X Cycle Error C 3 7.5 °e
Position Error ∆θ 2 15 min. of arc
Reliability
In addition to the absolute
maximum specifications of
codewheels, the environment
characteristics of the application
Glass Codewheel Tests
Test Duration Number of Parts Number of Failures
Storage at 100°C 1000 hours 44 0
Rotating at 100°C 500 hours 10 0
Temperature Cycle: -40°C to +100°C 500 cycles 98 0
Temperature/Humidity: 85°C/85% R.H. 500 hours 43 0
Film Codewheel Tests
Test Duration Number of Parts Number of Failures
Storage at 70°C 1000 hours 118 0
Rotating at 70°C 500 hours 10 0
Temperature Cycle: -40°C to +70°C 500 cycles 66 0
Temperature Cycle: +20°C to +40°C 1000 cycles 64 0
Temperature Cycle: +20°C to +55°C 1000 cycles 46 0
Temperature Cycle: +20°C to +70°C 500 cycles 50 0
tolerances unless otherwise
specified. Values are for worst
error over a full rotation. Please
refer to Encoder Module Data
Sheet for definitions of Encoding
characteristics.
are also important. For example,
consistent, large temperature
swings over the life of the product
will affect the codewheel
performance characteristics
depending on the material. The
following reliability table shows
results of lifetests under varying
conditions of temperature and
humidity.
2-130
Mounting with Module
Side A as the Mounting
Plane
Mounting a high resolution or
three channel encoder with
Module Side A as the mounting
plane requires alignment pins in
the motor base. These alignment
pins provide the necessary
centering of the module with
respect to the center of the motor
shaft. In addition to centering, the
codewheel gap is also important.
Please refer to the respective
encoder data sheet for necessary
mounting information.
*Please note that the image side of the codewheel must always be facing the module Side A.
Figure 1b shows mounting the
module with side B as the mount-
ing plane. When assembling the
encoder and codewheel, it is
important to maintain the
tolerances of Side A of the
module, and the image side of the
codewheel. See module Data
Sheets for these tolerances.
Figure 1a. Figure 1b.


MODULE SIDE B
MODULE SIDE A
IMAGE SIDE
OF CODEWHEEL
IMAGE SIDE
OF CODEWHEEL MODULE SIDE A
MODULE SIDE B

Mounting Rotary
Encoders with
Codewheels
There are two orientations for
mounting the HP encoder module
and HP codewheel. Figure 1a
shows mounting the module with
side A as the mounting plane.
Mounting with Module
Side B as the Mounting
Plane, using HP Assembly
Tools
Hewlett-Packard offers centering
tools and gap setting tools only
for the case when the module is
mounted with Side B down.
Please refer to the Ordering
Information Table to choose the
correct assembly tools.
2-131
MOTION SENSING
AND CONTROL
Figure 2. Alignment Tool is Used to Set Height of
Codewheel.
Assembly Instructions
Using HP Assembly Tools
Figure 3. Alignment Tool is Placed over Shaft and onto
Codewheel Hub. Alignment Tool Pins Mate with
Aligning Recesses on Module.
CENTERING TOOL
CODEWHEEL
ALIGNING RECESSES
MODULE SIDE A
MODULE SIDE B

IMAGE SIDE OF CODEWHEEL
GAP SETTING SHIM
CODEWHEEL
MODULE SIDE A
MODULE SIDE B


shim should not contact the
codewheel boss.
(b) Push codewheel down
against gap setting shim. The
codewheel is now at the proper
height.
(c) Tighten codewheel
setscrew.
3. Insert mounting screws
through module and thread
into the motor base. Do not
tighten screws.
Instructions
1. Place codewheel on shaft.
2. Set codewheel height:
(a) Place the correct gap
setting tool (per Ordering
Information Table) on motor
base, flush up against the
motor shaft as shown in Figure
2. The shim has two different
size steps. Choose the one that
most closely matches the width
of the codewheel boss. The
4. Slide the HEDS-8905 or HEDS-
8906 centering tool over
codewheel hub and onto
module as shown in Figure 3.
The pins of the alignment tool
should fit snugly inside the
alignment recesses of the
module.
5. While holding alignment tool in
place, tighten screws down to
secure module.
6. Remove alignment tools.
2-132
Mechanical Drawings
Figure 4. HEDS-5120 Codewheel. Figure 5. HEDS-6100 Codewheel.
Figure 6. HEDS-5140 Codewheel Used with HEDS-9140.
5.95
(0.234)
MAX.
12.70
(0.500)
MAX.
10.16
(0.400)
130° ± 5° 
TYPICAL
INDEX PULSE
POSITION
INDEX PULSE
REFERENCE
MARKER
25.7 (1.01)
DIA. MAX.
1.80
(0.071)
SETSCREW
3.58
(0.141)
MOUNTING BOSS
R
OP
= 11.00 mm (0.433 in.)
DIMENSIONS IN MM (INCHES)
26.67
(1.050)
MAX.
18.0
(0.71)
50.0 (1.97)
DIA.
8.99
(0.354)
MAX.
MOUNTING
BOSS
DIMENSIONS IN MM (INCHES)
# 2-56 SETSCREW
USE 0.035" HEX WRENCH
0.20
(0.008)
5.94
(0.234)
MAX.
12.70
(0.500)
MAX.
10.16
(0.400)
1.80
(0.071)
3.58
(0.141)
MOUNTING BOSS –
NOT USED ON
6 mm & 1/4"
I.D. HUBS
DIMENSIONS IN MM (INCHES)
# 2-56 SETSCREW
USE 0.035"
HEX WRENCH
25.40 (1.000) MAX.
0.04 MAX.
0.054
2-133
MOTION SENSING
AND CONTROL
Figure 7. HEDS-6140 Codewheel Used with HEDS-9040.
Figure 9. HEDM-6120 Codewheel/HEDM-6121 Codewheel.Figure 8. HEDM-5120 Codewheel/HEDM-5121 Codewheel.
26.67
(1.050)
MAX.
18.0
(0.71)
130°
TYPICAL
INDEX PULSE
POSITION
INDEX PULSE
REFERENCE
MARKER
50.6 (1.99)
DIA. MAX.
SETSCREW
8.99
(0.354)
MAX.
MOUNTING BOSS
R
OP
= 23.36 mm (0.920 in.)
DIMENSIONS IN MM (INCHES)
# 2-56 SETSCREW
USE 0.035" HEX WRENCH

0.18
(0.007)
2-56 SETSCREW
USE 0.035" HEX WRENCH
5.9 MAX.
10.2 MAX.
12.6 MAX.
ARTWORK SIDE
(HEDM-5120)
ARTWORK SIDE
(HEDM-5121)
DIA.
MAX.
25.56
(1.006)
DIMENSIONS IN mm (INCHES)

15.3 MAX.
4.2 MAX.
0.18
(0.007)
2-56 SETSCREW
USE 0.035" HEX WRENCH
8.5 MAX.
22.50
(0.886)MAX.
ARTWORK SIDE
(HEDM-6120)
ARTWORK SIDE
(HEDM-6121)
DIA.
MAX.
50.48
(1.980)
DIMENSIONS IN mm (INCHES)
36.5 18 MAX.
2-134
Figure 10. HEDG-5120 Codewheel/HEDG-5121 Codewheel. Figure 11. HEDG-6120 Codewheel/HEDG-6121 Codewheel.
Figure 12. HEDM-6140 Codewheel/HEDM-6141 Codewheel.


0.55
(0.022)
2-56 SETSCREW
USE 0.035" HEX WRENCH
5.51
(0.217)
10.2 MAX.
ARTWORK SIDE
(HEDG-5120)
ARTWORK SIDE
(HEDG-5121)
DIA.
MAX.
25.56
(1.006)
DIMENSIONS IN mm (INCHES)
12.6 MAX.
0.55
(0.022)
2-56 SETSCREW
USE 0.035" HEX WRENCH
8.43
(0.332)
17.98
(0.708)MAX.
ARTWORK SIDE
(HEDG-6120)
ARTWORK SIDE
(HEDG-6121)
DIA.
MAX.
50.48
(1.987)
DIMENSIONS IN mm (INCHES)


22.6 MAX. 25.4 MAX.
0.18
(0.007)
2-56 SETSCREW
USE 0.035" HEX WRENCH
8.43
(0.332)
22.50
(0.886)MAX.
ARTWORK SIDE
(HEDM-6140)
ARTWORK SIDE
(HEDM-6141)
DIA.
MAX.
50.48
(1.987)
DIMENSIONS IN mm (INCHES)


36.5
130°
TYPICAL
INDEX PULSE
POSITION
SETSCREW
2-135
MOTION SENSING
AND CONTROL
Ordering Information Encoder Modules, Codewheel and Assembly Tools
HEDS-9100 option
modules
HEDS-5120
codewheels
0
0Option
Resolution
(Cycles/Rev)
S - 50 CPR
K - 96 CPR
C - 100 CPR
D - 192 CPR
E - 200 CPR
F - 256 CPR
G - 360 CPR
H - 400 CPR
A - 500 CPR
I - 512 CPR
Shaft Diameter
01 - 2 mm
02 - 3 mm
03 - 1/8 in.
04 - 5/32 in.
05 - 3/16 in.
06 - 1/4 in.
11 - 4 mm
14 - 5 mm
12 - 6 mm
13 - 8 mm
Rop = 11 mm,
2 channels
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8905 8901
HEDS-9140 option
modules
HEDS-5140
codewheels
0
0Option
Shaft Diameter
01 - 2 mm
02 - 3 mm
03 - 1/8 in.
04 - 5/32 in.
05 - 3/16 in.
06 - 1/4 in.
11 - 4 mm
14 - 5 mm
12 - 6 mm
13 - 8 mm
Rop = 11 mm,
3 channels
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8905 8905
Resolution
(Cycles/Rev)
S - 50 CPR
K - 96 CPR
C - 100 CPR
E - 200 CPR
F - 256 CPR
G - 360 CPR
H - 400 CPR
A - 500 CPR
I - 512 CPR
HEDS-9000 option
modules
HEDS-6100
codewheels
0
0Option
Shaft Diameter
05 - 3/16 in.
06 - 1/4 in.
07 - 5/16 in.
08 - 3/8 in.
09 - 1/2 in.
10 - 5/8 in.
11 - 4 mm
12 - 6 mm
13 - 8 mm
Rop = 23 mm,
2 channels
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8906 8901
Resolution
(Cycles/Rev)
A - 500 CPR
B - 1000 CPR
Metal Codewheels
2-136
HEDS-9040 option
modules
HEDS-6140
codewheels
0
0Option
Resolution
(Cycles/Rev)
B - 1000 CPR
J - 1024 CPR
Shaft Diameter
05 - 3/16 in.
06 - 1/4 in.
07 - 5/16 in.
08 - 3/8 in.
09 - 1/2 in.
10 - 5/8 in.
11 - 4 mm
12 - 6 mm
13 - 8 mm
Rop = 23 mm,
3 channels
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8906 8906
Ordering Information (Cont’d.)
Note:
1. For the lower resolution, two channel encoders, (11 mm 512 CPR; 23 mm 1024 CPR) the centering tool and gap-settting shim
are not necessary, but sometimes helpful in an assembly process.
HEDS-9100
modules
option
Film Codewheels
0
0
Artwork Orientation
0 - Artwork on hub
side (Use when
module side B is
down)
1 - Artwork opposite
hub side (use when
module side A is
down)
Resolution
(Cycles/Rev)
B - 1000 CPR
J - 1024 CPR
Shaft Diameter
01 - 2 mm
02 - 3 mm
03 - 1/8 in.
04 - 5/32 in.
05 - 3/16 in.
06 - 1/4 in.
11 - 4 mm
14 - 5 mm
12 - 6 mm
13 - 8 mm
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8905 8901
Rop = 11 mm,
2 channels
HEDM-512
codewheels
option
2-137
MOTION SENSING
AND CONTROL
HEDS-9000
modules
option
HEDM-612
codewheels
option
0
0
Artwork Orientation
0 - Artwork on hub
side (Use when
module side B is
down)
1 - Artwork opposite
hub side (use when
module side A is
down)
Resolution
(Cycles/Rev)
T - 2000 CPR
U - 2048 CPR
Shaft Diameter
05 - 3/16 in.
06 - 1/4 in.
07 - 5/16 in.
08 - 3/8 in.
09 - 1/2 in.
10 - 5/8 in.
11 - 4 mm
12 - 6 mm
13 - 8 mm
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8906 8906
Rop = 23 mm,
2 channels
HEDS-9040
modules
option
HEDM-614
codewheels
option
0
0
Artwork Orientation*
0 - Artwork on hub
side (Use when
module side B is
down)
1 - Artwork opposite
hub side (use when
module side A is
down)
Resolution
(Cycles/Rev)
T - 2000 CPR
Shaft Diameter
05 - 3/16 in.
06 - 1/4 in.
07 - 5/16 in.
08 - 3/8 in.
09 - 1/2 in.
10 - 5/8 in.
11 - 4 mm
12 - 6 mm
13 - 8 mm
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8906 8906
Rop = 23 mm,
3 channels
Ordering Information (Cont’d.)
*Index will not work if wrong orientation is used.
2-138
Ordering Information (Cont’d.)
Glass Codewheels
HEDS-9100
modules
option
HEDG-512
codewheels
option
0
0
Artwork Orientation
0 - Artwork on hub
side (Use when
module side B is
down)
1 - Artwork opposite
hub side (use when
module side A is
down)
Resolution
(Cycles/Rev)
B - 1000 CPR
J - 1024 CPR
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8905 8932
Rop = 11 mm,
2 channels
HEDS-9000
modules
option
HEDG-612
codewheels
option
0
0
Artwork Orientation
0 - Artwork on hub
side (Use when
module side B is
down)
1 - Artwork opposite
hub side (use when
module side A is
down)
Resolution
(Cycles/Rev)
T - 2000 CPR
U - 2048 CPR
Assembly Tools
Centering Gap-Setting
HEDS- HEDS-
8906 8932
Rop = 23 mm,
2 channels
Shaft Diameter
05 - 3/16 in.
06 - 1/4 in.
07 - 5/16 in.
08 - 3/8 in.
09 - 1/2 in.
10 - 5/8 in.
11 - 4 mm
12 - 6 mm
13 - 8 mm
Shaft Diameter
01 - 2 mm
02 - 3 mm
03 - 1/8 in.
04 - 5/32 in.
05 - 3/16 in.
06 - 1/4 in.
11 - 4 mm
14 - 5 mm
12 - 6 mm
13 - 8 mm