Avtron Bullseye32™ Encoders

Avtron Bullseye32™ Encoders

Never Buy Another Hollow Shaft Encoder!

  • Replaces Hollow Shaft Models Directly
  • No Moving Wearing Parts
  • Universal 5-24V Operation
  • LED & Remote Alarm Diagnostics
  • -40°C to +100°C Operation
  • 2 Year No-Hassle Warranty
Outline Drawing

Want a super-simple, ultra-reliable OEM encoder?  Bullseye!
Avtron Bullseye32™ (AV32) encoders eliminate the top culprits that cause encoder failures: there are no bearings, no seals, no optics, no glass disks!
And they don't require expensive mounting flanges like other no-bearing encoders.

Bullseye32 self-centers without a pilot and mounts in seconds: Tighten the rotor clamp on the shaft, bolt the housing in place, and unlock the patented centering mechanism by removing the red end cap. Top it off with the shaft cap.  It's so simple, we've created a visual instruction sheet (in our documents tab) for installation.

Bullseye32 is protected against dust, dirt and water. Why waste installation time protecting encoders with baskets? How about a Bullseye instead - it's tougher than most "protective baskets"! And Bullseye32 includes complete self-diagnostics, right down to the signal quality and wiring!

Bullseye32 is also electrically tough: in addition to a built-in voltage regulator, Bullseye32 is fully protected from reverse voltage wiring and shorting.


Operating Power:
Volts: 5 - 24 VDC; Current: 60mA, no load
Output Format: A Quad B with gated marker (A,/A, B,/B, Z,/Z)
Frequency Range: 0 to 250 KHz
PPR: 32 - 5000

Speed: 6000 RPM Max., (for higher speeds, consult factory)
Temperature: -40° to 100°C
Environmental: IP65 Electronic Protection
Vibration: 5-2000Hz
Shock: 50G, 11mS duration
Weight: 0.7 lbs [350g]

All dimensions are in inches [millimeters].
Specifications and features are subject to change without notice.
  • Replaces HS25, HS35, HOG and many other hollow shaft models
  • Replaces H25® and many other shafted, flange-mounted encoders
  • Shrugs off dirt, oil, and water contamination
  • Wide-Gap™ technology
  • No protective basket needed
  • Includes wiring self-diagnostics and protection
  • Slashes installation time
  • Survives shaft runout errors
Industry General Food & Beverage Pulp & Paper Wood Products Wind Power Crane & Hoist Metals Mining Marine Oil & Gas

Light Mill Duty

AV20, AV25, AV6A, AV6M, Avtron Elevator Encoder, Cables and Connectors, Encoder Couplings, Encoder Programming Tool, HS25A, HS35A, HS6A, K661, SC65

Mill Duty

AV32, Cables and Connectors, Encoder Couplings, HS35M, HS35X, HS6M, K661, M185, M3, M3(small), RAHS35M

Heavy Mill Duty

AV115, AV125, AV44, AV45, AV56, AV56-Wind, AV56S, AV67, AV85, AV850, AVSK, Cables and Connectors, Carlen Replacement, HS44, HS45, K661, M4, M4(small), XP5, XR115, XR12, XR125, XR45, XR4F, XR5, XR56, XR67, XR85, XR850, XR97, XRB1, XRB2, XRB3

Severe Mill Duty

AV12, AV30, AV485, AV5, AV685, Cables and Connectors, Carlen Replacement, Encoder Couplings, HS40, K661, M484, M6, M6C, M7, XP5, XPH1, XPH8, XR12, XR485, XR5, XR685, XR97, XRB1, XRB2, XRB3,
Avtron Bullseye32™ Encoders replace a huge range of shafted and hollow shaft encoders.

BEI Encoders:
H20®, H25®, HS25, HS35

Dynapar Encoders:
HS20, HS35, HS35R

Encoder Products (EPC) Encoders
755A, 260, 702, 225A, 225Q, 25T, 25H

Hubner Encoders:
And many, many other models. 

All trademarks are the property of their respective owners.

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In This Section

  • A Quad B

    A Quad B refers to the set of output quadrature signals from an incremental quadrature encoder to indicate speed and direction, including complements: A, A NOT, B, B NOT (, , , ). Most Avtron encoders offer A Quad B output at no extra cost.  For more information on quadrature- Wikipedia: http://en.wikipedia.org/wiki/Quadrature_phase

  • C-Face

    A machined flange or elevated/recessed face provided on motors for mounting accessories. Typically provided on the drive end for gearbox/load mounting, C-faces may also be provided on the non-drive end for mounting encoders, brakes, and other accessories.

  • Contamination

    Also known as contaminants, such as water, dirt, dust, oil, and other compounds which enter an encoder through seal failure and can cause optical errors. If the contamination is abrasive, it can also cause bearing failures in the encoder. Modular encoders are very resistant to contamination as they use magnetoresistive sensors and have no bearings.

  • Encoder

    A device which indicates position and speed via a set of digital outputs. Incremental encoders output quadrature (A Quad B) signals, and may add a marker pulse once per revolution.  Absolute encoders typically indicate position via a digital message, a set of parallel outputs, or analog values.

  • Flange Adapter

    A Flange Adapter provides the NEMA 56C motor mounting face and properly locates the encoder shaft. The encoder shaft and motor shaft are then connected using a flexible coupling. (Drawing "A") Often flange adapters can be eliminated by directly mounting a modular encoder such as an Avtron AV125, AV850, AV56, AV67, AV85, AV115 unit on the motor flange. (Drawing "B")

  • Incremental Encoder

    An encoder that produces pulses in proportion to distance moved or rotated. Incremental encoders can also have a marker pulse Z, Z NOT (, ) once per revolution to provide a position reference. Avtron produces a full range of incremental rotary encoders.

  • Line Driver

    The chip or output circuit that forms the electrical pulses output from the encoder. Avtron has extremely advanced line driver technology to prevent damage from overvoltage and short circuits. Avtron offers optional high-power line drivers to permit Avtron encoder signals to travel farther down long wires to remote controller/drive locations without the need for repeaters or amplifiers.

  • Magnetic Encoder

    Magnetic and magnetoresistive encoders typically use a magnetized rotor with north and south poles lined up around the perimeter of the disk. A magnetoresistive sensor detects the transitions, and these are the counts or pulses generated by the encoder. Magnetic encoders withstand dirt, dust, water, and temperature changes far better than optical encoders.

  • Magnetic Rotor

    A magnetized disk with multiple north and south poles lined up around the perimeter of the disk. A magnetoresistive sensor detects the transitions and generates the pulses generated by the magnetic encoder.

  • Marker Pulse

    The Marker Pulse occurs once per revolution. The purpose of the marker pulse is to provide a repeatable home position location for positioning applications. The marker pulse is often abbreviated as "ØZ" or "Z" in the USA and "C" or "N" in Europe.

  • Mini-MS Connector

    This is a 10 pin military style connector used for encoders.  It includes a set of locking pins and slots instead of the threaded mating system on most MS connectors.  It is also known as "Mini-Twist-Lock", "Bayonet", and "Baldor connector".

  • Mini-Twist-Lock Connector

    This is a 10 pin military style connector used for encoders.  It includes a set of locking pins and slots instead of the threaded mating system on most MS connectors.  It is also known as "Bayonet", "MS Mini", and "Baldor connector".

  • Modular Encoders

    Modular Encoders mount to a machined C-face or flange adapter on the motor (drive or non-drive end). Modular encoders consist of a rotor that mounts on the shaft, and a stator that bolts to the motor frame. Modular encoders are very rugged, and Avtron encoders feature Wide-Gap sensors to avoid complex shimming or fitting to the motor. Modular C-face encoders are typically used on DC motors; but some AC motors, such as Rockwell’s RPM III AC and Marathon’s Blue and Black Max motors, have C-faces standard on the non-drive end for mounting an encoder.

  • MS Connector

    The most used encoder connector style in North America. Available in 6, 7, and 10 pin versions, with 10 pins being the most common. Avtron offers pin-for-pin exact replacements for competitors’ models using MS connectors. MS connectors are extremely reliable but require soldering. Many users prefer industrial EPIC ® style connectors instead. EPIC® is a registered trademark of the Lapp Group.

  • Optical Disk

    An Optical Disk is typically a glass, metal, or plastic disk with fine lines or slots etched around the perimeter that interrupt the beam of light from the light source to an optical sensor. Optical disks can be quite fragile. Avtron uses only shatterproof optical disks with Wide-Gap technology.

  • Optical Sensors

    Optical Sensors are typically phototransistors or other light sensors which sense the light emitted by the light source, as interrupted by, or passed through, the optical disk.

  • Pulses

    Pulses are also known as counts and are the low voltage output transitions which indicate movement of the encoder. Encoders are rated by resolution or PPR (pulses per revolution). Pulses are not the same as lines.

  • Quadrature

    To determine which direction an encoder is revolving, encoders output quadrature signals: two streams of pulses, A & B, generated at 90° timing angles. (Also called A Quad B) A leading B indicates rotation in one direction; B leading A indicates the encoder is rotating in the opposite direction. Example: “A leads B with clockwise rotation as viewed from the encoder face on an HS45 encoder." Many encoders with quadrature outputs also have complementary outputs: A NOT and B NOT signals.

  • Rotary Encoder

    A rotary encoder provides position and/or speed feedback information about a rotating shaft.  Rotary encoders may be hollow shaft, no-bearing modular, coupled solid shaft style.  They may provide absolute positioning information, or incremental velocity feedback. Avtron rotary encoders are designed and built to be far more reliable than ordinary rotary encoders. Avtron encoder white papers on our blog provide more details of how and why Avtron rotary encoders are more reliable.

  • Rotor

    The disk-shaped portion of the modular encoder that is mounted on the motor shaft. Avtron modular encoders use magnetic rotors.

  • Seal Failure

    Many encoders come sealed from the factory, but as they are temperature cycled, the air inside expands and contracts at a different rate from the air outside the encoder. This puts pressure on the seals of the encoder and eventually breaks them down, creating an unobstructed path to the inside of the encoder. Likewise, external pressure (wash-downs, submersion) creates the same path. If an encoder has seal failure, contaminants get into the encoder and cause errors in optical encoders. Avtron heavy mill duty and severe duty encoders are highly resistant to seal failure, and feature magnetic technology to ignore most contaminants.

  • Torque Arm

    A type of anti-rotation arm used to mount hollow shaft encoders to large frame motors. It features a threaded rod for adjustable radius.

  • Wide-Gap Technology

    Avtron encoders use special optical sensors and magnetoresistive sensors, combined with proprietary circuit designs to allow the sensor to be located much farther from the magnetic rotor or optical disk. This eliminates sensor crashes and makes mounting easy and forgiving of mechanical variation.

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