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Optical Rotary Encoders: The Basics

From Baumer Ltd.
 

 
On every factory, and on every shop floor, something is rotating and someone wants to monitor it. Enter the optical rotary encoder. Encoders transform mechanical rotary motion into a sequence of electrical pulses, which are in turn monitored for display or control functions through a counter, display, PC, PLC, tachometer or controller. Within the main classification of optical rotary encoders, there are three basic configurations: incremental, absolute and absolute multi-turn. All these styles contain the same basic components and operate under the same basic principle. First, we need to address the basic components of an encoder as shown in diagram I below: 1. Shaft/Hollow Shaft- connects to rotating object and transfers rotary motion to the pulse disc 2. Pulse Disc-disc with alternating clear/opaque segments which are photoelectrically scanned by an infrared light source. 3. Light Source-high quality infrared LED. 4. Grid Diaphragm- splits light source into an additional signal, phase shifted by 90°.
Products & Services
Absolute rotary encoders use optical, mechanical, or magnetic indexing for angular measurement. They do not lose their position after power-down, but instead provide absolute position upon power-up without requiring a home cycle or any shaft rotation. Search by Specification | Learn more about Absolute Rotary Encoders
Incremental rotary encoders are multi-turn sensors that use optical, mechanical, or magnetic index-counting for angular measurement. They contain no absolute reference, but instead count relative to the turn-on position. Search by Specification | Learn more about Incremental Rotary Encoders
Linear encoders sense and digitize linear position change for positional measurement and feedback to control systems. Search by Specification | Learn more about Linear Encoders
Rotary position sensors include potentiometers, resolvers and a variety of magnetic and capacitive technologies. Sensors are designed for angular displacement less than one turn or for multiturn displacement. Search by Specification | Learn more about Rotary Position Sensors
Product Announcements
Micro-Drives - Encoders
A range of different encoders is available for applications requiring an accurate control of motor velocity, direction of rotation, and positioning. The performance of a drive or servo system depends... (read more)
Gurley Precision Instruments - Low-Cost Model A37: Mini Rotary Absolute Encoder
The model A37 mini encoder is a 12-bit single-turn absolute rotary encoder with opto-electronic technology. These encoders are used in a wide variety of position-sensing applications for the measuring... (read more)
Gurley Precision Instruments - True Absolute Rotary Encoder
GPI improves the resolution of the A19 Low-Cost, True Absolute Rotary Encoder to 15 bits!... (read more)
Automation and Metrology, Inc. - ECN 1313 By Heidenhain
ECN 1313 Rotary encoder with integral bearing for integration in motors Mounted stator coupling Installation diameter 65 mm Taper shaft... (read more)
Gurley Precision Instruments - Virtual Absolute Technology
Gurley Precision Instruments has developed a unique encoding method that combines the simplicity of an incremental encoder with the reliability of an absolute encoder. (read more)
Excitron Corporation - Optical encoder with index and 800 ppr for motors
Optical rotary encoder mounted on the rear shaft of the motor for our stepper motors. Resolution is 800 pulses per revolutuion with an absolute index that you can use to further automate your... (read more)
Gurley Precision Instruments - GPI Model R112 - Smallest High Resolution Encoder.
GPI Models R112S and R112B optical rotary incremental encoders are designed for light industrial applications that require high resolution in a very small package. Available in either shafted or... (read more)
Heidenhain Corporation - Rotary Encoders for Common Automation Applications
In order to bridge the gap between resolvers and high-end rotary encoders in automated machine applications, HEIDENHAIN Corporation is now making available a line of inductive rotary encoders, the RIx... (read more)
Topics of Interest
Sensors and encoders are used everyday in manufacturing environments and high precision equipment to monitor the proximity or presence of an object, as well as the position, distance, direction, and... (Read More)
The Optical Encoders typically consist of a rotating and a stationary member. The rotor is usually a metal, glass, or a plastic disc mounted on the encoder shaft. The disc has some kind of optical... (Read More)
The purpose of an encoder is to act as a position feedback device as part of an integrated control system. The encoder is an electro-optomechanical device that attaches to a rotating shaft providing... (Read More)
Rotary and linear encoders are standard equipment in today's automated motion systems. Both types, generally, are optically based, relying on light passing through or reflecting off a scale and then... (Read More)
Absorption: The portion of optical attenuation in an optical fiber resulting from the conversion of optical power to heat; caused by impurities such as hydroxyl ions in the fiber. A/B Switch: A... (Read More)
See more product announcements for Absolute Rotary Encoders
ECN 1313 By Heidenhain

ECN 1313 By Heidenhain
Automation and Metrology, Inc.


Absolute Encoder AD 34

Absolute Encoder AD 34
Dynapar Corp.


9360 Rotary Dual Output Hall Effect Sensor

9360 Rotary Dual Output Hall Effect Sensor
BEI Duncan Electronics


11 See more product announcements for Absolute Rotary Encoders