EM1_WEB Features
- Two-channel quadrature with optional index
- Improved replacement for HEDS-9000 Series
- Single 5 VDC supply
- Resolutions from 32 to 2,500 CPR
- Internal decoupling capacitor
- Sink/source 8mA outputs

EM1 Product Description
The EM1 is a transmissive optical encoder module designed to detect rotary or linear position when paired together with an encoder disk or linear strip. The EM1 consists of a lensed LED source and a monolithic detector IC enclosed in a small polymer package. The EM1 uses phased array detector technology to provide superior performance and greater tolerances over traditional aperture mask-type encoders.
The EM1 provides digital A & B quadrature outputs with an optional third output index channel. Each EM1 module is resolution-specific and is matched to the resolution of an encoder disk or linear strip. The EM1 module now supports all standard resolutions offered by the HEDS-9000 series encoder module and additional resolutions. The EM1 operates with a single 5V supply and provides single-ended outputs capable of sinking and sourcing 8mA. An internal 0.1 µF decoupling capacitor is designed into the EM1 to provide enhanced noise immunity over the HEDS-9000 series encoder modules.
For open collector and higher voltage applications, add the PC3 cable driver, or for differential cable driver outputs, add the PC4 cable driver. Encoder disks, linear strips, quadrature decoder chips, counter chips, computer interface boards, mating connectors, and cables are also available.
Mechanical Drawings
Specifications
COMPATIBLE 1" & 2" DISKS
1" DISKS | ||||
CPR | MODULE Non-Index |
1" DISK Non-Index |
MODULE Index |
1" DISK Index |
---|---|---|---|---|
32 | EM1-1-32-N | DISK-1-32-*-NE | ||
50 | EM1-1-50-N | DISK-1-50-*-NE | EM1-1-50-I | DISK-1-50-*-IE |
96 | EM1-1-100-N | DISK-1-96-*-NE | EM1-1-100-I | DISK-1-96-*-IE |
100 | EM1-1-100-N | DISK-1-100-*-NE | EM1-1-100-I | DISK-1-100-*-IE |
120 | EM1-1-100-N | DISK-1-120-*-NE | ||
192 | EM1-1-200-N | DISK-1-192-*-NE | EM1-1-200-I | DISK-1-192-*-IE |
200 | EM1-1-200-N | DISK-1-200-*-NE | EM1-1-200-I | DISK-1-200-*-IE |
250 | EM1-1-250-N | DISK-1-250-*-NE | EM1-1-250-I | DISK-1-250-*-IE |
256 | EM1-1-250-N | DISK-1-256-*-NE | EM1-1-250-I | DISK-1-256-*-IE |
360 | EM1-1-360-N | DISK-1-360-*-NE | EM1-1-360-I | DISK-1-360-*-IE |
400 | EM1-1-400-N | DISK-1-400-*-NE | EM1-1-400-I | DISK-1-400-*-IE |
500 | EM1-1-500-N | DISK-1-500-*-NE | EM1-1-500-I | DISK-1-500-*-IE |
512 | EM1-1-512-N | DISK-1-512-*-NE | EM1-1-512-I | DISK-1-512-*-IE |
540 | EM1-1-540-N | DISK-1-540-*-NE | EM1-1-540-I | DISK-1-540-*-IE |
720 | EM1-1-720-N | DISK-1-720-*-NE | EM1-1-720-I | DISK-1-720-*-IE |
800 | EM1-1-800-N | DISK-1-800-*-NE | EM1-1-800-I | DISK-1-800-*-IE |
900 | EM1-1-900-N | DISK-1-900-*-NE | EM1-1-900-I | DISK-1-900-*-IE |
1000 | EM1-1-1000-N | DISK-1-1000-*-NE | EM1-1-1000-I | DISK-1-1000-*-IE |
1024 | EM1-1-1024-N | DISK-1-1024-*-NE | EM1-1-1024-I | DISK-1-1024-*-IE |
1250 | EM1-1-1250-N | DISK-1-1250-*-NE | EM1-1-1250-I | DISK-1-1250-*-IE |
*Represents the bore size | ||||
2" DISKS | ||||
CPR | MODULE Non-Index |
2" DISK Non-Index |
MODULE Index |
2" DISK Index |
64 | EM1-1-32-N | DISK-2-64-*-NE | ||
100 | EM1-1-50-N | DISK-2-100-*-NE | EM1-1-50-I | DISK-2-100-*-IE |
200 | EM1-1-100-N | DISK-2-200-*-NE | EM1-1-100-I | DISK-2-200-*-IE |
400 | EM1-1-200-N | DISK-2-400-*-NE | EM1-1-200-I | DISK-2-400-*-IE |
500 | EM1-2-500-N | DISK-2-500-*-NE | EM1-2-500-I | DISK-2-500-*-IE |
512 | EM1-2-500-N | DISK-2-512-*-NE | EM1-2-500-I | DISK-2-512-*-IE |
800 | EM1-1-400-N | DISK-2-800-*-NE | EM1-1-400-I | DISK-2-800-*-IE |
1000 | EM1-2-1000-N | DISK-2-1000-*-NE | EM1-2-1000-I | DISK-2-1000-*-IE |
1024 | EM1-2-1024-N | DISK-2-1024-*-NE | EM1-2-1024-I | DISK-2-1024-*-IE |
1800 | EM1-2-1800-N | DISK-2-1800-*-NE | EM1-2-1800-I | DISK-2-1800-*-IE |
2000 | EM1-2-2000-N | DISK-2-2000-*-NE | EM1-2-2000-I | DISK-2-2000-*-IE |
2048 | EM1-2-2048-N | DISK-2-2048-*-NE | EM1-2-2048-I | DISK-2-2048-*-IE |
2500 | EM1-2-2500-N | DISK-2-2500-*-NE | EM1-2-2500-I | DISK-2-2500-*-IE |
*Represents the bore size |
COMPATIBLE 1" & 2" HUBDISKS
1" HUBDISKS | ||||
CPR | MODULE Non-Index |
1" HUBDISK Non-Index |
MODULE Index |
1" HUBDISK Index |
---|---|---|---|---|
32 | EM1-1-32-N | HUBDISK-1-32-*-NE | ||
50 | EM1-1-50-N | HUBDISK-1-50-*-NE | EM1-1-50-I | HUBDISK-1-50-*-IE |
96 | EM1-1-100-N | HUBDISK-1-96-*-NE | EM1-1-100-I | HUBDISK-1-96-*-IE |
100 | EM1-1-100-N | HUBDISK-1-100-*-NE | EM1-1-100-I | HUBDISK-1-100-*-IE |
120 | EM1-1-100-N | HUBDISK-1-120-*-NE | ||
192 | EM1-1-200-N | HUBDISK-1-192-*-NE | EM1-1-200-I | HUBDISK-1-192-*-IE |
200 | EM1-1-200-N | HUBDISK-1-200-*-NE | EM1-1-200-I | HUBDISK-1-200-*-IE |
250 | EM1-1-250-N | HUBDISK-1-250-*-NE | EM1-1-250-I | HUBDISK-1-250-*-IE |
256 | EM1-1-250-N | HUBDISK-1-256-*-NE | EM1-1-250-I | HUBDISK-1-256-*-IE |
360 | EM1-1-360-N | HUBDISK-1-360-*-NE | EM1-1-360-I | HUBDISK-1-360-*-IE |
400 | EM1-1-400-N | HUBDISK-1-400-*-NE | EM1-1-400-I | HUBDISK-1-400-*-IE |
500 | EM1-1-500-N | HUBDISK-1-500-*-NE | EM1-1-500-I | HUBDISK-1-500-*-IE |
512 | EM1-1-512-N | HUBDISK-1-512-*-NE | EM1-1-512-I | HUBDISK-1-512-*-IE |
540 | EM1-1-540-N | HUBDISK-1-540-*-NE | EM1-1-540-I | HUBDISK-1-540-*-IE |
720 | EM1-1-720-N | HUBDISK-1-720-*-NE | EM1-1-720-I | HUBDISK-1-720-*-IE |
800 | EM1-1-800-N | HUBDISK-1-800-*-NE | EM1-1-800-I | HUBDISK-1-800-*-IE |
900 | EM1-1-900-N | HUBDISK-1-900-*-NE | EM1-1-900-I | HUBDISK-1-900-*-IE |
1000 | EM1-1-1000-N | HUBDISK-1-1000-*-NE | EM1-1-1000-I | HUBDISK-1-1000-*-IE |
1024 | EM1-1-1024-N | HUBDISK-1-1024-*-NE | EM1-1-1024-I | HUBDISK-1-1024-*-IE |
1250 | EM1-1-1250-N | HUBDISK-1-1250-*-NE | EM1-1-1250-I | HUBDISK-1-1250-*-IE |
*Represents the bore size | ||||
2" HUBDISKS | ||||
CPR | MODULE Non-Index |
2" HUBDISK Non-Index |
MODULE Index |
2" HUBDISK Index |
64 | EM1-1-32-N | HUBDISK-2-64-*-NE | ||
100 | EM1-1-50-N | HUBDISK-2-100-*-NE | EM1-1-50-I | HUBDISK-2-100-*-IE |
200 | EM1-1-100-N | HUBDISK-2-200-*-NE | EM1-1-100-I | HUBDISK-2-200-*-IE |
400 | EM1-1-200-N | HUBDISK-2-400-*-NE | EM1-1-200-I | HUBDISK-2-400-*-IE |
500 | EM1-2-500-N | HUBDISK-2-500-*-NE | EM1-2-500-I | HUBDISK-2-500-*-IE |
512 | EM1-2-500-N | HUBDISK-2-512-*-NE | EM1-2-500-I | HUBDISK-2-512-*-IE |
800 | EM1-1-400-N | HUBDISK-2-800-*-NE | EM1-1-400-I | HUBDISK-2-800-*-IE |
1000 | EM1-2-1000-N | HUBDISK-2-1000-*-NE | EM1-2-1000-I | HUBDISK-2-1000-*-IE |
1024 | EM1-2-1024-N | HUBDISK-2-1024-*-NE | EM1-2-1024-I | HUBDISK-2-1024-*-IE |
1800 | EM1-2-1800-N | HUBDISK-2-1800-*-NE | EM1-2-1800-I | HUBDISK-2-1800-*-IE |
2000 | EM1-2-2000-N | HUBDISK-2-2000-*-NE | EM1-2-2000-I | HUBDISK-2-2000-*-IE |
2048 | EM1-2-2048-N | HUBDISK-2-2048-*-NE | EM1-2-2048-I | HUBDISK-2-2048-*-IE |
2500 | EM1-2-2500-N | HUBDISK-2-2500-*-NE | EM1-2-2500-I | HUBDISK-2-2500-*-IE |
*Represents the bore size |
COMPATIBLE LINEAR STRIPS
LPI | MODULE Non-Index |
Linear Strip Non-Index |
MODULE Index |
Linear Strip Index |
---|---|---|---|---|
120 | EM1-0-120-N | LIN-120-*-N | EM1-0-120-I | LIN-120-*-# |
127 | EM1-0-127-N | LIN-127-*-N | EM1-0-127-I | LIN-127-*-# |
150 | EM1-0-150-N | LIN-150-*-N | EM1-0-150-I | LIN-150-*-# |
180 | EM1-0-180-N | LIN-180-*-N | EM1-0-180-I | LIN-180-*-# |
200 | EM1-0-200-N | LIN-200-*-N | EM1-0-200-I | LIN-200-*-# |
250 | EM1-0-250-N | LIN-250-*-N | EM1-0-250-I | LIN-250-*-# |
300 | EM1-0-300-N | LIN-300-*-N | EM1-0-300-I | LIN-300-*-# |
360 | EM1-0-360-N | LIN-360-*-N | EM1-0-360-I | LIN-360-*-# |
500 | EM1-0-500-N | LIN-500-*-N | EM1-0-500-I | LIN-500-*-# |
* Represents length of Linear Strip | * Represents length of Linear Strip # Represents location of Index |
ENVIRONMENTAL
Parameter | Value | Units |
---|---|---|
Operating Temperature | -40 to 100 | C |
Electrostatic Discharge, IEC 61000-4-2 | ± 4 | kV |
Vibration (10Hz to 2kHz, sinusoidal) | 20 | G |
Shock (6 milliseconds, half-sine) | 75 | G |
OPERATING CONDITIONS
PARAMETER | MIN. | MAX. | UNITS |
---|---|---|---|
A/B Output Frequency | 0 | 300 | kHz |
Disk RPM | 0 | (18 x 10^6) / CPR | RPM |
Linear Strip Speed | 0 | (3 x 10^5) / LPI | inches/sec. |
Disk/Linear Strip Radial Position Tolerance | ±.005 | inch |
ELECTRICAL SPECIFICATIONS
- Specifications apply over the entire operating temperature range.
- Typical values are specified at Vcc = 5.0V and 25C.
PARAMETER | MIN. | TYP. | MAX. | UNITS | CONDITIONS |
---|---|---|---|---|---|
Supply Voltage | 4.5 | 5.0 | 5.5 | V | Ripple < 100 mVpp |
Supply Current, EM1-0- (linear strip) | 27 | 33 | mA | LPI < 300, no load | |
54 | 65 | mA | LPI ≥ 300, no load | ||
Supply Current, EM1-1- (1" disk) | 27 | 33 | mA | CPR < 500, no load | |
54 | 65 | mA | CPR ≥ 500, no load | ||
Supply Current, EM1-2- (2" disk) | 27 | 33 | mA | CPR < 1000, no load | |
54 | 65 | mA | CPR ≥ 1000, no load | ||
Low-level Output | 0.5 | V | IOL = 8mA max. | ||
0.05 | V | No load | |||
High-level Output | 2.0 | V | IOH = -8mA max. | ||
4.8 | V | No load | |||
Output Current Per Channel | -8 | 8 | mA | ||
Load Capacitance | 100 | pF | |||
Output Rise Time | 110 | nS | |||
Output Fall Time | 100 | nS |
TIMING CHARACTERISTICS
ENCODING CHARACTERISTICS:
- Specifications apply over the entire operating temperature range.
- Values are for the worst error over full rotation.
- Refer to the timing diagram below.
PARAMETER | SYMBOL | MIN. | TYP. | MAX. | UNITS |
---|---|---|---|---|---|
Symmetry | X, Y | 150 | 180 | 210 | °e |
Quadrature | Z | 60 | 90 | 120 | °e |
Index Pulse Width | Po | 40 | 90 | 120 | °e |
Ch. I Rise After Ch. B or Ch. A Fall | t1 | 50 | 100 | 200 | ns |
Ch. I Fall After Ch. B or Ch. A Rise | t2 | -10 | 15 | 25 | ns |
TIMING DIAGRAM:
CPR: The number of Cycles (C) of the A or B outputs Per Revolution.
Cycle Error: An indication of cycle uniformity. The difference between an observed shaft angle which gives rise to one electrical cycle, and the nominal angular increment of 1/CPR of a revolution.
Index (I): The index output goes high once per revolution, coincident with the low states of channels A and B, nominally 1/4 of one cycle (90 °e).
LPI: Lines Per Inch. The number of Cycles (C) of the A or B output per inch of linear strip movement.
One Shaft Rotation: 360 mechanical degrees.
One Electrical Degree (°e): 1/360th of one cycle.
One Cycle (C): 360 electrical degrees (°e). Each cycle can be decoded into 1 or 4 states, referred to as X1 or X4 resolution multiplication.
PPR: The number of resolvable Positions Per Revolution of the encoder disk with x4 quadrature decoding.
Quadrature (Z): The phase lag or lead between channels A and B in electrical degrees, nominally 90 °e.
Symmetry: A measure of the relationship between (X) and (Y) in electrical degrees, nominally 180°e.
INSTALLATION TORQUE
PARAMETER | TORQUE |
---|---|
Mounting Screws | 3.5-4 in-lbs |
EM1 / HEDS COMPARISON
US Digital is the designer and manufacturer of the EM1 transmissive optical encoder module. The design of the EM1 provides electrical and mechanical compatibility with HEDS-9000, HEDS-9100, HEDS-9200, HEDS-9040, and HEDS-9140 series modules.
The process of switching from the HEDS to the EM1 module should not require any mechanical or electrical changes. Simply use the EM1 and matching codewheel in place of the HEDS module and codewheel. The EM1 has a built-in index channel available on most resolutions, for both rotary disks and linear strips. The EM1 uses a US Digital designed codewheel with 2 tracks rather than 3 tracks for index versions. The EM1 offers improved output drive capability and will source and sink 8mA at TTL levels.
Physically, the EM1 has no external wire loops which can interfere when mounting. The connector pins are 0.051" shorter than HEDS modules, while still providing .30" insertion depth. US Digital's EM1 offers custom resolutions.
PIN-OUTS
Pin | Description |
---|---|
1 | Ground |
2 | Index |
3 | A channel |
4 | +5VDC power |
5 | B channel |
Notes
- US Digital® warrants its products against defects in materials and workmanship for two years. See complete warranty for details.
Configuration Options |
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EM1_WEB | - | Type 0 (Linear Strip) 1 (1" Disk) 2 (2" Disk) | - | Resolution 120 LPI 127 LPI 150 LPI 180 LPI 200 LPI 250 LPI 300 LPI 360 LPI 500 LPI 32 CPR 50 CPR 64 CPR 100 CPR 100 CPR 200 CPR 200 CPR 250 CPR 360 CPR 400 CPR 400 CPR 500 CPR 500 CPR 512 CPR 540 CPR 720 CPR 800 CPR 800 CPR 900 CPR 1000 CPR 1024 CPR 1250 CPR 1000 CPR 1024 CPR 1800 CPR 2000 CPR 2048 CPR 2500 CPR | - | Index I (Index) N (Non-Index) | ||||||||||||||||||||||||||||||||||||||||||
PLEASE NOTE: This chart is for informational use only. Certain product configuration combinations are not available. Visit the EM1_WEB product page for pricing and additional information. |