E2 Optical Kit Encoder

E2 Features

  • Quick, simple assembly, and disassembly
  • Rugged screw-together housing
  • Accepts .010 in. axial shaft play
  • 32 to 5,000 cycles per revolution (CPR)
  • 128 to 20,000 pulses per revolution (PPR)
  • 2 channel quadrature TTL squarewave outputs
  • Optional index (3rd channel)
  • Mounting compatibility with HEDS-5500

See more info below

Configure the E2

E2 Product Description

Restriction of Hazardous Substances

The E2 is a rotary encoder with a rugged glass-filled polymer enclosure, which utilizes either a 5-pin locking or standard connector. The internal components consist of a mylar disk mounted to a precision machined aluminum hub and an encoder module. The module contains a highly collimated solid-state light source and monolithic phased array sensor, which together provide a system extremely tolerant to mechanical misalignments.

The E2 is normally designed for applications of 10 feet or less. For applications requiring longer cable lengths, we recommend adding a PC4 / PC5 differential line driver or check out our E5 which has an optional differential output.

Attachment of the base to a surface may be accomplished by utilizing one of several machine screw bolt circle options. Positioning of the base to the centerline of a shaft is ensured by the use of our centering tool. The cover is securely attached to the base with two 4-40 pan head screws to provide a resilient package protecting the internal components.

Connection to the E2 product is made through either a 5-pin locking or standard connector. The mating connectors are available from US Digital with several cable options and lengths.


US Digital's E2 encoder may be used as direct replacements for Avago HEDM-5500, HEDM-5600, HEDS-5500, HEDS-5600.

Product Specifications

View here or download the specifications


Operating Temperature, CPR < 2000 -40 to 100 C
Operating Temperature, CPR ≥ 2000 -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


Max. Shaft Axial Play ±0.010 in.
Max. Shaft Runout 0.004 T.I.R. in.
Max. Acceleration 250000 rad/sec²
For CPR ≤ 1250:
Max. RPM (1)
Max. A/B Frequency
e.x. CPR=1250, Max. RPM=14400
e.x. CPR=100, Max. RPM=60000

minimum value of ((18 x 10^6) / CPR) and (60000)

For CPR = 2000, 2048, 2500:
Max. RPM (1)
Max. A/B Frequency

minimum value of ((21.6 x 10^6) / CPR) and (60000)

For CPR = 4000, 4096, 5000:
Max. RPM (1)
Max. A/B Frequency

minimum value of ((43.2 x 10^6) / CPR) and (60000)

Typical Product Weight 0.56 oz.
Codewheel Moment of Inertia 8.0 x 10^-6 oz-in-s²
Hub Set Screw #4-48  
Hex Wrench Size 0.050 in.
Encoder Base plate Thickness 0.135 in.
3 Mounting Screw Size #0-80  
2 Mounting Screw Size #2-56 or #4-40  
3 Screw Bolt Circle Diameter 0.823 ± 0.005 in.
2 Screw Bolt Circle Diameter 0.750 ± 0.005 in.
Required Shaft Length (2)(3)
  With E-option (3)
  With H-option
0.445 to 0.575
0.445 to 0.805
> 0.445
Index Alignment to Hub Set Screw 180 Typical degrees
Technical Bulletin TB1001 - Shaft and Bore Tolerances Download


(1) 60000 RPM is the maximum rpm due to mechanical considerations. The maximum rpm due to the module's maximum frequency response is dependent upon the module’s resolution (CPR).

(2) Add 0.125" to the required shaft length when using R-option.

(3) Including Axial play.


Hub Set Screw 2-3 in-lbs
Cover Screw 2-4 in-lbs
Base Mounting Screw (#0-80) 1-2 in-lbs
Base Mounting Screw (#2-56) 2-3 in-lbs
Base Mounting Screw (#4-40) 4-6 in-lbs
Adapter Plate Mounting Surface (#2-56 screws) 2-3 in-lbs
Adapter Plate Mounting Surface (#4-40 screws) 4-6 in-lbs


B leads A for clockwise shaft rotation, and A leads B for counterclockwise rotation viewed from the cover side of the encoder.


  • Specifications apply over the entire operating temperature range.
  • Typical values are specified at Vcc = 5.0Vdc and 25°C.
  • For complete details, see the EM1 or EM2 product pages.
Supply Voltage 4.5  5.0 5.5 V  
Supply Current   27 33 mA CPR < 500, no load 
  54 62 mA CPR ≥ 500 and < 2000, no load
  72 85 mA CPR ≥ 2000, no load
Low-level Output     0.5 V IOL = 8mA max., CPR < 2000
    0.5 V IOL = 5mA max., CPR ≥ 2000
  0.25   V no load, CPR ≥ 2000
High-level Output 2.0     V IOH = -8mA max. and CPR < 2000
2.0     V IOH = -5mA max. and CPR ≥ 2000
  4.8   V no load and CPR < 2000
  3.5   V no load and CPR ≥ 2000
Output Current Per Channel -8   8 mA CPR < 2000
-5   5 mA CPR ≥ 2000
Output Rise Time   110   nS CPR < 2000
  50   nS CPR ≥ 2000, ± 5mA load
Output Fall Time   100   nS CPR < 2000
  50   nS CPR ≥ 2000, ± 5mA load


1 Ground
2 Index
3 A channel
4 +5VDC power
5 B channel

Note: 5-pin single-ended mating connector is CON-C5 or CON-LC5


1. Centering Tool

Part #: CTOOL - (Shaft Diameter)
Description: This reusable tool provides a simple method for accurately centering the E2 base onto the shaft, promoting hub to base concentricity and thus accuracy.

It is recommended for the following situations:

  • When using mounting screws smaller than #4-40.
  • When the position of the mounting holes is in question.
  • When using the 3-hole mounting pattern.

2. Hex Tool

Depending on the order packaging option, either a hex driver or hex wrench is included.

Part #: HEXD-050 (only included with -B or -1 packaging options)
Description: Hex driver, 0.050" flat-to-flat for #4-48 set screws.

3. Spacer Tool

A spacer tool is included for all packaging options.

Part #: SPACER-E2

4. Screws

Part #: SCREW-080-250-PH
Description: Pan Head, Philips #0-80 UNF x 1/4"
Use: Base Mounting
Quantity Required: 3
Screws are not included

Part #: SCREW-256-250-PH
Description: Pan Head, Philips #2-56 UNC x 1/4"
Use: Base Mounting
Quantity Required: 2
Screws are not included

Part #: SCREW-440-250-PH
Description: Pan Head, Philips #4-40 UNC x 1/4"
Use: Base Mounting
Quantity Required: 2
Screws are not included

Part #: SCREW-440-625-PH
Description: Pan Head, Phillips 4-40 UNC x 5/8"
Use: Cover Mounting
Quantity Required: 2
Screws are included

Part #: SCREW-448-063-SS
Description: Socket Head Set Screw, 4-48 UNC x 1/16"
Use: Hub/Disk Mounting for 5/16" - 10mm Bore
Quantity Required: 1
Screw is included

Part #: SCREW-448-125-SS
Description: Socket Head Set Screw, 4-48 UNC x 1/8"
Use: Hub/Disk Mounting for 2mm - 1/4" Bore
Quantity Required: 1
Screw is included


Title Date Description Download
E2 & H1 Material Change - 7191 8/22/2022 As part of our ongoing continuous improvement program, as well as considering the current state of the plastics industry supply chain disruptions, US Digital has decided to focus on the standardization of our plastic encoder components. Based on this, the E2 and the H1 encoder covers and bases will be changing from PBT 20% GF
(polybutylene terephthalate) to PC 20% GF (polycarbonate). This change has no impact on the form, fit and function of these encoders.
E2, E5 Packaging - PCN 7190 8/31/2021 As part of our ongoing continuous improvement efforts, US Digital is implementing a change to the individual packaging options of our E2 and E5 kit encoders. It is important to note that this change will not affect the bulk packaging option, also known as our “B” packaging option. Download
HUBDISK-1 Packaging Change Notification - PCN 6297 4/30/2018 As part of our ongoing continuous improvement efforts, US Digital is implementing a change to the packaging of our 1-inch Hubdisk assemblies.

We are replacing the current plastic tube packaging with a 25-count plastic tray. The tray is a two-piece design with a snap-on lid and anti-static coated for ESD-sensitive environments. This change is designed to enhance the ease of handling for our customers, easy removal of the individual hubdisk, and protection against potential damage due to long-term storage of hubdisk assemblies.

This change does not affect the form, fit, or function of the final product.
Hub Set Screw Production Change - PCN 5367 7/20/2015 As part of our ongoing continuous improvement efforts, US Digital is implementing a change related to the production of our 5/16" (.313), 8mm (.315), 3/8" (.375), and 10mm (.394) HUBDISK assemblies. We are adding a low-strength threadlocker to the set screw during our assembly process to assist in securing the set screw in the hub during transportation. This will aid in the set screw retention of these specific hub sizes; ensuring the retention is sufficient and avoid the potential of them backing out of the hub assembly during transit. This change does not affect form, fit, or function. Download
E2 Mold Update - PCN 5258 4/22/2015 As part of our ongoing continuous improvement efforts, and in order to enhance both function and appearance of the E2 product line, multiple improvements are being incorporated into a plastic component redesign.

EM1 & EM2 Update - PCN 4199 1/14/2014 Based on our continuous process improvement program, US Digital is changing the current marking method for our EM1 and EM2 encoder modules to a serialization method. This change will allow for each module to have a unique code; the current marking method is based on a date code system that includes all encoder modules produced within a specific week/year. The serialization system will be based on a hexadecimal system. Download
EM1 LED Die - PCN 1016 2/7/2013 As part of US Digital's continual assurance of supply strategy, we have qualified additional sources for our LED die used in our EM1 encoder module, which in turn impacts all of the following products:

EM1, E2, E3, E5, E6, H1, H15, H3, H5, H6, HB5M, HB6M, HD25, PE, S1, S2, S5, S6, T5 and T6

The device specification will remain the same, i.e. there will be no change to form, fit, or function of the product(s) as specified by US Digital. The appropriate quality and reliability testing have been performed on representative products to ensure normal parametric distribution, consistent with US Digital's quality and reliability standards.

Additional Information

Product Notes

  • US Digital® warrants its products against defects in materials and workmanship for two years. See complete warranty for details.
  • Cables and connectors are not included and must be ordered separately.


Assembly Instructions

Related Pages

3D Model Downloads

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