Avtron AV85 THIN-LINE III™ Encoders

Avtron AV85 THIN-LINE III™ Encoders


  • Heavy Mill Duty
  • Simple, Secure Installation
  • All models are protected against all short circuits and wiring errors
  • Wide-Gap Technology: No Sensor Scraping or Adjustment
  • Up to 50000 PPR
  • No Couplings or Bearings
  • Sealed Electronics
  • Self-Diagnostic LED and Alarm Output
  • Universal 5-24V Operation
  • 3 Year No-Hassle Warranty
Outline Drawing
AV85 THIN-LINE III™ heavy mill duty modular magnetic encoders fit standard 8.5" C-Face motors and 8.5" flanges commonly used for NEMA brake mounting. Other THIN-LINE III models, ranging from 115mm to 6.75", are available to fit other motor sizes, and AV125 is available for 12.5" NEMA brake applications.

The AV85 is perfect for brake motor applications where the encoder is sandwiched between the motor and brake.  With a real-world installation history of over 4,500,000 hour MTBF, you don't have to worry about replacing the encoder!

THIN-LINE III encoders feature simple installation, durable construction, and clear diagnostics to eliminate encoder-related downtime: First, the magnetic sensors are fully potted to withstand dirt and liquids.  No glass disks, no optics to clog. There are no moving, wearing parts!  The patented Wide-Gap™ Cam Screw Rotors™ put an end to sensor damage, are simpler to install, and stay securely mounted to the shaft.  The universal 5-24V design drives longer cables and is protected against wiring errors and surges.  When you power up an AV85, you know you installed it right: the green light tells you the digital self-tuning has set your AV85 optimally.  If at any time the AV85 cannot produce ideal signals, the LED changes to red and the remote alarm contact activates.  However, the encoder keeps working to give you time to schedule service.  Any time there are wiring errors, the LED changes to orange.  AV85 is the ideal solution to keep your motor and drive system running 24/7/365!
Operating Power: Volts: 5 - 24 VDC; Current: 80mA, no load
Output Format: A Quad B with Marker (A,A–, B,B–, Z,Z–)
Second Isolated Output: Optional
Frequency Range: @5V, @1m cable, 250 kHz Max
                               @24V, @300m cable, #8 output, 45 kHz Max   
Maximum Cable Length: 1000' 
PPR: 4 - 50000
Speed: 5400 RPM Max. std., for higher speeds, consult factory
Electronics: Fully Encapsulated, IP67 (see manual for details)
Temperature: -40° to 100°C (150°C rotor)
Vibration: 18 g’s
Shock: 1 meter drop test
Chemical: Polyurethane enamel paint protects against salt spray, mild acids, and bases.
Weight:  2 - 3 lbs [0.9 - 1.36 kg]

All dimensions are in inches [millimeters]; Specifications and features are subject to change without notice.
  • Replaces Avtron M85, Northstar/Dynapar™ D8, D850, S8, S85, S850, SL85, ST85; online cross reference guide available
  • Shrugs off dirt, oil, and water contamination
  • Highly resistant to electrical and magnetic motor and brake noise
  • Patented Cam Screw Rotor™ eliminates rotor slipping
  • Built-in motor position guide and diagnostic check
  • No air gap adjustment required
  • Corrosion-resistant coating on all metal surfaces
  • Second C-face included for outboard brake/accessory mount
  • Sealed thru-shaft option
  • Fits shafts 0.500" - 3.188" [10 - 85 mm]
  • 4,500,000+ hour MTBF design
Industry General Food & Beverage Pulp & Paper Wood Products Wind Power Crane & Hoist Metals Mining Marine Oil & Gas

Light Mill Duty

AV20, AV25, AV32, AV6A, AV6M, HS25A, HS35A, HS6A, HS6M, K661,

Mill Duty

AV32, HS35M, K661, M185, M3, M3(small), RAHS35M

Heavy Mill Duty

AV115, AV125, AV45, AV5, AV56, AV56S, AV67, AV85, AV850, AV850Test, AVSK, Carlen Replacement, HS45, K661, M4, M4(small), XR115, XR12, XR125, XR45, XR4F, XR5, XR56, XR85, XR850, XR97, XRB1, XRB2

Severe Mill Duty

AV12, AV30, AV485, AV5, AV685, Carlen Replacement, HS40, K661, M484, M6, M6C, M7, XR12, XR485, XR5, XR685, XR97, XRB1, XRB2,
Avtron's AV85 encoders directly replace competitive models, including:

Contrex:  7200-0990, 7300-1602, 7300-1612, 7300-1622

Lakeshore/Northstar: SL85, S8, D8, S850, D850

And other 8.5" C-face and FC-Face mount encoder models.
For direct model replacements, try our cross reference page
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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

  • Cam Screw Rotor™

    A Cam Screw Rotor eliminates the problems associated with slipping rotors of other types; it uses two cam (eccentric) head screws. The screws are preloaded into the rotor; simply rotate them (approximately 90°-180°) to fully engage the shaft (4-6 ft-lbs) using a standard hex (Allen) wrench. Cam screw rotors are available on AV850, AV56, AV67, AV85, and AV115 THIN-LINE II™ encoders. Cam Screw Rotor Patent # 7,485,997. Cam Screw Rotor™ is a trademark of Avtron.

  • 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.

  • Heavy Mill Duty

    Heavy Mill Duty encoders are designed to withstand temperature cycling, extreme temperatures, contaminants, bearing loads, and physical force.

  • Industrial EPIC

    The preferred encoder connector of most users in North America. It contains a full size terminal strip and, unlike the MS connector, requires no soldering for quick field connections. Avtron offers pin-for-pin exact replacements for competitors’ models using industrial EPIC® style connectors. EPIC® is a registered trademark of the Lapp Group.

  • 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.

  • Magnetoresistive Sensor

    A sensor that detects the magnetic poles on an encoder's magnetic rotor and transforms them into pulses. Avtron magnetoresistive (MR) sensors use advanced technology to reject external magnetic signals such as brake solenoids and motor magnetic fields. MR sensors enable Avtron magnetic encoders to ignore dirt, oil, water, and other contaminants.

  • 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.

  • 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.


    A NEMA FC face mount is a 8.5" flange with (4) bolts located in a 7.25" circle. Originally used for mounting solid shaft, coupled tachometers using flange adapters, the NEMA FC 8.5" face is a standard for mounting modular encoders. (Drawing "A") Avtron AV85 and AV850 encoders mount directly on NEMA FC 8.5" faces. (Drawing "B")

  • PPR

    Pulses Per Revolution. Most Avtron encoders output quadrature pulses, with four times as many lines as pulses. Often lines can be counted in the drive/speed controller for higher resolution applications.

  • 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.

  • Resolution

    Resolution describes how many individual slices or positions can be reported by an incremental or absolute encoder.  For incremental encoders the number of PPR (pulses per revolution) expresses resolution; for absolute encoders, PPR, or counts per turn or bits of resolution may be listed.

  • Sandwich

    An older style of encoder that fits between an existing solid shaft coupled tachometer and the motor. It is commonly replaced by modular encoders such as the Avtron AV56 THIN-LINE II™.

  • 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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