High Temperature 125

C Two

Channel Optical Incremental
Encoder Modules

Technical Data

HEDT-9000
HEDT-9100

Features

ˇ High Performance

ˇ High Resolution

ˇ Low Cost

ˇ Easy to Mount

ˇ No Signal Adjustment

Required

ˇ Insensitive to Radial and

Axial Play

ˇ Small Size

ˇ -40

C to 125

C Operating

Temperature

ˇ Two Channel Quadrature

Output

ˇ TTL Compatible

ˇ Single 5 V Supply

Description

The HEDT-9000 and the HEDT-
9100 series are high
performance, low cost, optical
incremental encoder modules that
operate to 125

C. When used with

a codewheel, these modules
detect rotary position. The
modules consist of a lensed (LED)
source and a detector IC enclosed
in a small C-shaped plastic pack-
age. Due to a highly collimated
light source and unique
photodetector array, these
modules are extremely tolerant to
mounting misalignment.

The two channel digital outputs
and the single 5 V supply input
are accessed through five 0.025
inch square pins located on 0.1
inch centers.

ESD WARNING: NORMAL HANDLING PRECAUTIONS SHOULD BE TAKEN TO AVOID STATIC
DISCHARGE.

Package Dimensions

26.67 (1.05)

HEDS-9X00

15.2

(0.60)

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 ą 0.10

(0.040 ą 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 ą 0.05

(0.147 ą 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 ą 0.10

(0.070 ą 0.004)

2.92 ą 0.10

(0.115 ą 0.004)

10.2

(0.400)

5.46 ą 0.10

(0.215 ą 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)

11.9

(0.47)

4.75 ą 0.10

(0.187 ą 0.004)

2.9

(0.11)

1.8

(0.07)

6.9 (0.27)

GND

5 CH. B

4 V

3 CH. A

2 N.C.

1 GND

SIDE A

SIDE B

TYPICAL DIMENSIONS IN

MILLIMETERS AND (INCHES)

Standard resolutions for the
HEDT-9000 are 500 CPR and
1000 CPR for use with a HEDS-
6100 codewheel or equivalent.
For the HEDT-9100, standard
resolutions between 96 CPR and
512 CPR are available for use
with a HEDS-5120 codewheel or
equivalent.

Applications

The HEDT-9000 and 9100
provide sophisticated motion
detection at a low cost, at
temperatures to 125

C, making

them ideal for high volume
automotive applications.

Note: Agilent Technologies
encoders are not recommended
for use in safety critical
applications. Eg. ABS braking
systems, power steering, life
support systems and critical care
medical equipment. Please
contact sales representative if
more clarification is needed.

Theory of Operation

The HEDT-9000 and 9100 are C-
shaped emitter/detector modules.
Coupled with a codewheel, they
translate the rotary motion of a
shaft into a two-channel digital
output.

As seen in the block diagram,
each 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 polyetherimide
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
product the digital waveforms.

The codewheel rotates between
the emitter and detector, causing
the light beam to be interrupted

Block Diagram

Output Waveforms

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 code-
wheel. 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 through the

signal processing circuitry
resulting in A, A, B, and B. Two
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).

Definitions

Count (N):

The number of bar

and window pairs or counts per
revolution (CPR) of the
codewheel.

Absolute Maximum Ratings

Storage Temperature, T

S .....................................................................

-40

C to 125

Operating Temperature, T

A ................................................................

-40

C to 125

Supply Voltage, V

CC ......................................................................................

- 0.5 V to 7 V

Output Voltage, V

O ........................................................................................

-0.5 V to V

Output Current per Channel, I

out .................................................

-1.0 mA to 5 mA

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

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

State Width Error (

S):

The

deviation, in electrical degrees, of
each state width from its ideal
value of 90

Phase (

The number of elec-

trical 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 (

The deviation

of the phase from its ideal value
of 90

Direction of Rotation:

When the

codewheel rotates in the direction
of the arrow on top of the

module, channel A will lead
channel B. If the codewheel
rotates in the opposite direction,
channel B will lead channel A.

Optical Radius (R

The dis-

tance from the codewheel's center
of rotation to the optical center
(O.C.) of the encoder module.

Recommended Operating Conditions

Parameter

Symbol

Min.

Typ.

Max.

Units

Notes

Temperature

-40

125

Supply Voltage

4.5

5.5

Volts

Ripple < 100 mV

p-p

Load Capacitance

100

3.3 k

pull-up resistor

Count Frequency

100

kHz

Velocity (rpm) x N

Note: The module performance is guaranteed to 100 kHz but can operate at higher frequencies.

Encoding Characteristics

Encoding Characteristics over Recommended Operating Range and Recommended Mounting Tolerances.
These Characteristics do not include codewheel/codestrip contributions.

Description

Sym.

Typ.

Case 1 Max.

Case 2 Max.

Units

Notes

Pulse Width Error

Logic State Width Error

Phase Error

Case 1: Module mounted on tolerance circle of

0.13 mm (

0.005 in.).

Case 2: HEDT-9000 mounted on tolerances of

0.50 mm (0.020").

HEDT-9100 mounted ontolerances of

0.38 mm (0.015").

Electrical Characteristics

Electrical Characteristics over Recommended Operating Range, typical at 25

Parameter

Symbol

Min.

Typical

Max.

Units

Notes

Supply Current

High Level Output Voltage

2.4

Volts

= -40

A max.

Low Level Output Voltage

0.4

Volts

= 3.2 mA

Rise Time

200

= 25 pF

Fall Time

= 11 k

pull-up

Recommended Codewheel Characteristics

Figure 1. Codestrip Design.

Codewheel Options

Optical

HEDS

CPR

Radius

Series

(N)

Option

mm (in.)

5120

11.00 (0.433)

5120

100

11.00 (0.433)

5120

192

11.00 (0.433)

5120

200

11.00 (0.433)

5120

256

11.00 (0.433)

5120

360

11.00 (0.433)

5120

400

11.00 (0.433)

5120

500

11.00 (0.433)

5120

512

11.00 (0.433)

6100

500

23.36 (0.920)

6100

1000

23.36 (0.920)

Parameter

Symbol

Minimum

Maximum

Units

Notes

Window/Bar Ratio

0.7

1.4

Window Length

1.8 (0.07)

2.3 (0.09)

mm (inch)

Absolute Maximum

+ 1.9 (0.075)

mm (inch)

Includes eccentricity

Codewheel Radius

errors

Part Number HEDT-9000

Document Outline