EM2 Features
- Two-channel quadrature with index
- High-resolution version of EM1
- Single 5V supply
- Rotary versions up to 10,000 CPR
- Linear versions up to 2,000 CPI
- Internal decoupling capacitor
- Outputs source/sink 5 mA
EM2 Product Description
The EM2 is a transmissive optical encoder module designed to provide up to 4x higher resolution than the EM1. The module detects rotary or linear movement when paired with an encoder disk or linear strip. The EM2 consists of a lensed LED source and a monolithic detector IC enclosed in a small polymer package identical to the EM1. The EM2 uses phased array detector technology allowing for a wider gap tolerance and excellent tolerance to some disk contamination.
The EM2 provides digital A & B quadrature outputs with a third output index channel. Each EM2 module is resolution-specific and is matched to the resolution of an encoder disk. The EM2 operates with a single 5V supply and provides single-ended outputs capable of sinking and sourcing 5mA. An internal 0.1 µF decoupling capacitor is designed into the EM2 to provide enhanced noise immunity.
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, quadrature decoder chips, counter chips, computer interface boards, mating connectors, and cables are also available.
Download the EM2/EM1 comparison chart.
Mechanical Drawings
Specifications
COMPATIBLE 1" & 2" DISKS
| 1" DISKS | ||
| CPR | MODULE Index |
1" DISK Index |
|---|---|---|
| 2000 | EM2-1-2000-I | DISK-1-2000-*-IE |
| 2048 | EM2-1-2048-I | DISK-1-2048-*-IE |
| 2500 | EM2-1-2500-I | DISK-1-2500-*-IE |
| 4000 | EM2-1-4000-I | DISK-1-4000-*-IE |
| 4096 | EM2-1-4096-I | DISK-1-4096-*-IE |
| 5000 | EM2-1-5000-I | DISK-1-5000-*-IE |
| *Represents the bore size | ||
| 2" DISKS | ||
| CPR | MODULE Index |
2" DISK Index |
| 3600 | EM2-2-3600-I | DISK-2-3600-*-IE |
| 4000 | EM2-2-4000-I | DISK-2-4000-*-IE |
| 4096 | EM2-2-4096-I | DISK-2-4096-*-IE |
| 5000 | EM2-2-5000-I | DISK-2-5000-*-IE |
| 7200 | EM2-2-7200-I | DISK-2-7200-*-IE |
| 8000 | EM2-2-8000-I | DISK-2-8000-*-IE |
| 8192 | EM2-2-8192-I | DISK-2-8192-*-IE |
| 10000 | EM2-2-10000-I | DISK-2-10000-*-IE |
| *Represents the bore size | ||
COMPATIBLE 1" & 2" HUBDISKS
| 1" HUBDISKS | ||
| CPR | MODULE Index |
1" HUBDISK Index |
|---|---|---|
| 2000 | EM2-1-2000-I | HUBDISK-1-2000-*-IE |
| 2048 | EM2-1-2048-I | HUBDISK-1-2048-*-IE |
| 2500 | EM2-1-2500-I | HUBDISK-1-2500-*-IE |
| 4000 | EM2-1-4000-I | HUBDISK-1-4000-*-IE |
| 4096 | EM2-1-4096-I | HUBDISK-1-4096-*-IE |
| 5000 | EM2-1-5000-I | HUBDISK-1-5000-*-IE |
| *Represents the bore size | ||
| 2" HUBDISKS | ||
| CPR | MODULE Index |
2" HUBDISK Index |
| 3600 | EM2-2-3600-I | HUBDISK-2-3600-*-IE |
| 4000 | EM2-2-4000-I | HUBDISK-2-4000-*-IE |
| 4096 | EM2-2-4096-I | HUBDISK-2-4096-*-IE |
| 5000 | EM2-2-5000-I | HUBDISK-2-5000-*-IE |
| 7200 | EM2-2-7200-I | HUBDISK-2-7200-*-IE |
| 8000 | EM2-2-8000-I | HUBDISK-2-8000-*-IE |
| 8192 | EM2-2-8192-I | HUBDISK-2-8192-*-IE |
| 10000 | EM2-2-10000-I | HUBDISK-2-10000-*-IE |
| *Represents the bore size | ||
COMPATIBLE LINEAR STRIPS
| LPI | MODULE Non-Index |
Linear Strip Non-Index |
MODULE Index |
Linear Strip Index |
|---|---|---|---|---|
| 1000 | EM2-0-1000-N | LIN-1000-*-N | EM2-0-1000-I | LIN-1000-*-# |
| 2000 | EM2-0-2000-N | LIN-2000-*-N | EM2-0-2000-I | LIN-2000-*-# |
| * Represents length of Linear Strip | * Represents length of Linear Strip # Represents location of Index |
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ENVIRONMENTAL
| Parameter | Value | Units |
|---|---|---|
| Operating Temperature | -25 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 | NOTES |
|---|---|---|---|---|
| A/B Output Frequency | 0 | 360 | kHz | 2000, 2048, 2500 CPR (1") 3600, 4000, 4096, 5000 CPR (2") 1000 CPI (Linear) |
| 0 | 720 | kHz | 4000, 4096, 5000 CPR (1") 7200, 8000, 8192, 10000 CPR (2") 2000 CPI (Linear) |
|
| Disk RPM | 0 | (21.6 x 10^6) / CPR | RPM | 2000, 2048, 2500 CPR (1") 3600, 4000, 4096, 5000 CPR (2") |
| 0 | (43.2 x 10^6) / CPR | RPM | 4000, 4096, 5000 CPR (1") 7200, 8000, 8192, 10000 CPR (2") |
|
| Linear Strip Speed | 0 | 360 | in./sec. | 1000, 2000 CPI (Linear) |
| Disk/Linear Strip Radial Position Tolerance | ± .005 | inch |
ELECTRICAL SPECIFICATIONS
- Specifications apply over the entire operating temperature/voltage 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 | 72 | 85 | mA | no load | |
| Low-level Output | 0.5 | V | IOL = 5 mA | ||
| 0.25 | V | no load | |||
| High-level Output | 2.0 | V | IOH = -5 mA | ||
| 4.0 | V | no load | |||
| Output Current Per Channel | -5 | 5 | mA | ||
| Load Capacitance | 100 | pF | |||
| Output Rise Time | 50 | nS | ± 5 mA load | ||
| Output Fall Time | 50 | nS | ± 5 mA load |
TIMING CHARACTERISTICS
ENCODING CHARACTERISTICS:
- Specifications apply over the entire operating temperature/voltage 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 | 108 | 190 | 252 | °e |
| Quadrature | Z | 45 | 90 | 135 | °e |
| Index Pulse Width | Po | 40 | 90 | 135 | °e |
| Ch. I Rise After Ch. B or Ch. A Fall | t1 | -40 | ns | ||
| Ch. I Fall After Ch. B or Ch. A Rise | t2 | 25 | ns |
TIMING DIAGRAM:
CPI: The number of Cycles (C) of the A or B output Per Inch of linear strip movement.
CPR: The number of Cycles (C) of the A or B outputs Per 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).
One Shaft Rotation: 360 mechanical degrees.
One Electrical Degree (°e): 1/360th of one cycle.
One Cycle: 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 |
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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| EM2 | - | Type 0 (Linear Strip) 1 (1" Disk) 2 (2" Disk) | - | Resolution 1000 LPI 2000 LPI 2000 CPR 2048 CPR 2500 CPR 4000 CPR 4096 CPR 5000 CPR 3600 CPR 4000 CPR 4096 CPR 5000 CPR 7200 CPR 8000 CPR 8192 CPR 10000 CPR | - | Index I (Index) N (Non-Index) | |||||||||||||||||||||
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PLEASE NOTE: This chart is for informational use only. Certain product configuration combinations are not available. Visit the EM2 product page for pricing and additional information. |
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