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

Encoder accuracy is the ability of or limit to the encoder to repeat the exact same signals, given the exact same mechanical position.  Accuracy and resolution may be independent--an encoder can have higher accuracy than resolution, and vice versa.  Avtron incremental encoders are typically accuracy rated at +/-1 count of their resolution; Avtron absolute encoder accuracy varies by model.

A device used to prevent hollow shaft encoders from spinning with the shaft rotation. It is also called a tether or a torque arm. To prevent encoder bearing damage, anti-rotation arms are very flexible and permit all movements, including axial shaft movement but not rotation.

A flange used on European IEC frame motors to mount encoders (analogous to the NEMA 56C flange).  6 holes are located on a 100mm bolt circle, surrounding an 85mm flange.  Avtron offers the AV45 heavy duty encoder which directly fits the B10 flange, as well as the AV115 bearingless encoder which can be adapted to the B10 flange.

Also known as complementary outputs. To ensure that signal noise does not cause errors between the encoder and the controller, many encoders output signals that are driven in exactly opposite directions: when A goes high, A NOT goes low (, ); when A goes low, A NOT goes high. Controllers which see a transition in A, but not in the A NOT signal, would report a quadrature error.

Refers to a flexible device that is used to link a solid shaft encoder to the shaft to be monitored. Avtron strongly recommends isolated, flexible disk style couplings wherever possible to maximize encoder bearing life. For large axial shaft movement, splined couplings should be used.

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.

Foot Mount encoders are bolted to a motor foot, shelf, or other nearby location. The solid shaft encoder is coupled to the shaft to be monitored. Modern Avtron encoders (AV485) require a separate foot mounting bracket. To eliminate coupling and alignment maintenance issues, foot mounting installations can be upgraded to a hollow shaft encoder such as the AV685.

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

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.

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 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.

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.

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.

The high-speed switching of variable frequency drives that is used to control the speed of motors often produces current which flows from the motor shaft to ground, or from end-to-end of the motor.  These current are highly destructive to both motor and encoder bearings.  Preventing shaft current damage is essential.  Most Avtron hollow shaft encoders include features to prevent motor shaft current damage.  For more information:  http://www.avtronencoders.com/knowledge-base/eliminating-damage-from-motor-shaft-currents-through-tachometers-and-encoders or visit Wikipedia:  http://en.wikipedia.org/wiki/Shaft_voltage

Magnetoresistive (MR) sensors are used in Avtron encoders to provide high accuracy and superior reliability versus optical sensing systems.  For more information on magnetoresistivity:  Wiki:  http://en.wikipedia.org/wiki/Magnetoresistive

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.

An Optical Encoder typically uses a light source shining through, or reflecting off, an optical disk with lines or slots that interrupt the beam of light to an optical sensor. Electronics count the interruptions of the beam and generate the encoder’s output pulses.

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 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.

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.

A PY Face is a 2.0" flange with (4) bolts located in a 3.978" circle. It is used for mounting solid shaft, coupled 5PY style DC tachogenerators using flange adapters. Avtron M925 digital encoders fit PY face mount. An adapter is available to fit AV485 to PY faces as well.

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.

Failures of the encoder to generate properly formatted quadrature signals. Most typically, these are failures to create the proper 90° signal separation between the A and B channel outputs, with a less than perfect stream of square waves. Most controllers, when presented with a quadrature error, will report a drive fault or encoder fault and then shut down.

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.

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.

Solid Shaft encoders are coupled to the shaft to be measured. The solid shaft encoder body is typically C-Face mounted using a flange adapter, or some models can be foot mounted.

Total Indicated Runout. This is a measurement of how much a shaft wobbles with each revolution (shaft runout).

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

Incremental and absolute encoder signals should be carried over twisted pair cables.  Twisted pair cables enable the elimination of external noise signals, as the signals show up as "common mode" noise on both wires in the pair.  The controller wired for differential communication will remove the external noise from the encoder signal.  When wiring Avtron incremental encoders, be sure to wire the complementary signals (ex: A, A/) in one twisted pair.  Do not mix phased signals (ex: A, B) in the same twisted pair.  For absolute encoders, follow the bus recommendations for using the twisted pairs in the required cable type.

UL Listed Avtron encoders can be directly applied to any hazardous duty application which requires Class and Division, Class and Zone or AEX certification.  Note that UL Listing is a different system than ATEX or IECEx.  Ensure the model you select has the UL listing which meets the application requirements.