2
Package Dimensions
HEDS-9x00
HEDS-9x01
Theory of Operation
The HEDS-9000 and 9100 are C-shaped emitter/detec-
tor 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 polycarbon ate 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 detec-
tor, causing the light beam to be interrupted by the pat-
tern of spaces and bars on the code wheel. The photo-
diodes which detect these interruptions are arranged in
a pattern that corresponds to the radius and design of
the ode wheel. These detectors are also spaced such that
a light period on one pair of detectors corre sponds to a
dark period on the adjacent pair of detectors. The photo-
diode outputs are then fed through the signal process-
ing circuitry resulting in A, A, B, and B. Two comparators
receive these signals and produce the nal outputs for
channels A and B. Due to this integrated phasing tech-
nique, the digital output of channel A is in quadrature
with that of channel B (90 degrees out of phase).
26.67 (1.05)
HEDS-9X00
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
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.
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 ± 0.10
(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 N.C.
1 GND
SIDE A SIDE B
TYPICAL DIMENSIONS IN MILLIMETERS AND (INCHES)
* GAP MEASUREMENT TO THE SURFACE WINDOW = 1.68
±
0.10 (0.066
±
0.004)
** HEIGHT TO THE WINDOW = 3.02
±
0.10 (0.119
±
0.004)
26.67 (1.05)
HEDS-9X01
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 V CC
3 CH. A
2 N.C.
1 GND
SIDE A SIDE B
4.01 ± 0.20
(0.158 ± 0.008)
16.76 ± 0.20
(0.66 ± 0.008)
TYPICAL DIMENSIONS IN MILLIMETERS AND (INCHES)
* GAP MEASUREMENT TO THE SURFACE WINDOW = 1.68
±
0.10 (0.066
±
0.004)
** HEIGHT TO THE WINDOW = 3.02
±
0.10 (0.119
±
0.004)