Two and Three Channel
Codewheels for Use with Agilent
Optical Encoder Modules
Technical Data
HEDS-51X0/61X0 Series
HEDG-512X/612X Series
HEDM-512X/61XX Series
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
Agilent Technologies offers a
wide variety of codewheels for
use with Agilent’s HEDS-9000,
HEDS-9100, HEDS-9040, and
HEDS-9140 series Encoder
Modules. Designed for many
environments, applications, and
budgets, Agilent 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
2
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.
Parameter
Storage
Temperature
Operating
Temperature
Humidity
Velocity
Shaft Axial Play
Shaft Eccentricity
Plus Radial Play
Acceleration
Symbol
T
S
T
A
HEDS-XXXX
Metal Codewheels
-40°C to +100°C
-40°C to +100°C
HEDM-XXXX
Film Codewheels
-40°C to +70°C
-40°C to +70°C
non condensing
HEDG-XXXX
Glass Codewheels
-40°C to +100°C
-40°C to +100°C
30,000 RPM
±
0.25 mm
(± 0.010 in)
±
0.1 mm
(± 0.004 in) TIR
250,000 Rad/Sec
2
30,000 RPM
±
0.175 mm
(± 0.007 in)
±
0.04 mm
(± 0.0015 in) TIR
250,000 Rad/Sec
2
12,000 RPM
±
0.175 mm
(± 0.007 in)
±
0.04 mm
(± 0.0015 in) TIR
100,000 Rad/Sec
2
Recommended Operating Conditions
Parameter
Maximum Count Frequency
Shaft Perpendicularity
Plus Axial Play
Shaft Eccentricity Plus
Radial Play
HEDS-XXXX
Metal Codewheels
100 kHz
±
0.25 mm
(± 0.010 in)
±
0.1 mm
(± 0.004 in) TIR
HEDM-XXXX
Film Codewheels
200 kHz*
±
0.175 mm
(± 0.007 in)
±
0.04 mm
(± 0.0015 in) TIR
HEDG-XXXX
Glass Codewheels
200 kHz
±
0.175 mm
(± 0.007 in)
±
0.04 mm
(± 0.0015 in) TIR
Note: Agilent 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.
3
Encoding Characteristics
Encoding characteristics over
recommended operating range
and recommended mounting
Part Number
HEDS-51XX
HEDS-61XX
HEDM-512X
HEDM-61XX
HEDG-512X
HEDG-612X
tolerances unless otherwise
specified. Values are for worst
error over a full rotation. Please
refer to Encoder Module Data
Symbol
∆C
∆θ
∆C
∆θ
∆C
∆θ
∆C
∆θ
∆C
∆θ
∆C
∆θ
Min.
Sheet for definitions of Encoding
characteristics.
Description
Cycle Error
Position Error
Cycle Error
Position Error
Cycle Error
Position Error
Cycle Error
Position Error
Cycle Error
Position Error
Cycle Error
Position Error
Typ.
3
10
3
7
3
4
3
2
3
4
3
2
Max.
5.5
40
5.5
20
7.5
40
7.5
20
7.5
30
7.5
15
Units
°e
min. of arc
°e
min. of arc
°e
min. of arc
°e
min. of arc
°e
min. of arc
°e
min. of arc
Reliability
In addition to the absolute
maximum specifications of
codewheels, the environment
characteristics of the application
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.
Glass Codewheel Tests
Test
Storage at 100°C
Rotating at 100°C
Temperature Cycle: -40°C to +100°C
Temperature/Humidity: 85°C/85% R.H.
Duration
1000 hours
500 hours
500 cycles
500 hours
Number of Parts
44
10
98
43
Number of Failures
0
0
0
0
Film Codewheel Tests
Test
Storage at 70°C
Rotating at 70°C
Temperature Cycle: -40°C to +70°C
Temperature Cycle: +20°C to +40°C
Temperature Cycle: +20°C to +55°C
Temperature Cycle: +20°C to +70°C
Duration
1000 hours
500 hours
500 cycles
1000 cycles
1000 cycles
500 cycles
Number of Parts
118
10
66
64
46
50
Number of Failures
0
0
0
0
0
0
4
Mounting Rotary
Encoders with
Codewheels
There are two orientations for
mounting the Agilent encoder
module and Agilent codewheel.
Figure 1a shows mounting the
module with side A as the
mounting plane. Figure 1b shows
mounting the module with side B
as the mounting 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.
MODULE SIDE B
IMAGE SIDE
OF CODEWHEEL
MODULE SIDE A
IMAGE SIDE
OF CODEWHEEL
MODULE SIDE A
MODULE SIDE B
Figure 1a.
Figure 1b.
*Please note that the image side of the codewheel must always be facing the module Side A.
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.
Mounting with Module
Side B as the Mounting
Plane, using Agilent
Assembly Tools
Agilent 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.
5
Assembly Instructions Using
Agilent Assembly Tools
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
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.
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.
IMAGE SIDE OF CODEWHEEL
CENTERING TOOL
CODEWHEEL
GAP SETTING SHIM
MODULE SIDE A
CODEWHEEL
MODULE SIDE A
ALIGNING RECESSES
MODULE SIDE B
MODULE SIDE B
Figure 2. Alignment Tool is Used to Set Height of
Codewheel.
Figure 3. Alignment Tool is Placed over Shaft and onto
Codewheel Hub. Alignment Tool Pins Mate with
Aligning Recesses on Module.