--- title: What is a rotary encoder and how does it work? description: Find out how encoders detect and control precise movements in industrial automation and mechanical engineering, and what technologies and applications are available. image: https://news.contelec.ch/hubfs/drehgeber.jpeg --- 4 min read # What is a rotary encoder and how does it work? [Roger Zingg ](https://news.contelec.ch/funktionale-sicherheit/author/roger-zingg)Aug 21, 2025 8:30:00 AM Share article ![Facebook](https://news.contelec.ch/hubfs/144894419/2025-assets/social/share.svg) - [![Facebook](https://news.contelec.ch/hubfs/144894419/2025-assets/social/facebook.svg) Facebook ](https://www.facebook.com/sharer/sharer.php?u=https://news.contelec.ch/funktionale-sicherheit/what-is-a-rotary-encoder) - [![Instagram](https://news.contelec.ch/hubfs/144894419/2025-assets/social/instagram.svg) Instagram ](https://www.instagram.com/share?url=https://news.contelec.ch/funktionale-sicherheit/what-is-a-rotary-encoder) - [![LinkedIn](https://news.contelec.ch/hubfs/144894419/2025-assets/social/linkedin.svg) LinkedIn ](https://www.linkedin.com/shareArticle?mini=true&url=https://news.contelec.ch/funktionale-sicherheit/what-is-a-rotary-encoder&title=What%20is%20a%20rotary%20encoder%20and%20how%20does%20it%20work?&summary=&source=) ![](https://news.contelec.ch/hs-fs/hubfs/drehgeber.jpeg?width=300&name=drehgeber.jpeg) What is a rotary encoder and how does it work? 6:42 Rotary encoders, also known as angle sensors, angle encoders or encoders, are indispensable components in industrial automation, mechanical engineering and many other technical applications. They enable the precise measurement of rotary movements and positions. Machines can thus be efficiently controlled and monitored. Β  What is a rotary encoder? A rotary encoder is a sensor that converts the rotary movement of an axis into an electrical signal. This signal can be used by control systems to precisely record the position, speed or direction of a movement, position, speed or direction of a movement. Rotary encoders are crucial for automated systems in many applications. They enable precise and reliable acquisition of movement data. ### Areas of application for rotary encoders: - Industrial automation: Position control of robots, machine control - [Vehicle technology](https://www.contelec.ch/en/products/product-worlds/mobile-vehicles): Steering angle detection, engine control, pedal position - [Medical technology](https://www.contelec.ch/produkte/produktwelten/medizin): Precision control in diagnostic devices, surgical robots - [Renewable energies:](https://www.contelec.ch/produkte/produktwelten/energie) Speed and blade angle monitoring of wind turbines ### How does a rotary encoder work? Rotary encoders typically consist of three components: - The measuring body can consist of a magnetic encoder or an encoder disk, for example, and is connected to the rotating axis of the machine. - The sensor system detects the movement and converts it into an electrical signal. - The electronic interface transmits the signals to a controller or a display. The function of rotary encoders is based on various measuring principles, which are divided into two main categories: ### Incremental encoders #### Functionality: An [incremental](https://www.contelec.ch/en/products/technologies/incremental) encoder generates a certain number of pulses per revolution. By counting these pulses, the speed or relative position can be determined. #### Advantages: - High resolution possible - Simple design and cost efficiency - Ideally suited for speed detection #### Disadvantages: - No absolute value (position is lost in the event of a power failure) #### Application example: πŸ”΅Β In CNC machines for detecting the speed of a spindle ### [Absolute rotary encoder](https://www.contelec.ch/en/products/product-lines/absolute-rotary-encoders) #### Functionality: Absolute encoders measure the exact angular position of an axis and output this as a digital value. They are available in singleturn (measures position in one revolution) or multiturn (measures position and number of revolutions)versions. #### Advantages: - Saves position even after a power failure - Direct angle measurement possible - Greater safety thanks to exact position data #### Disadvantages: ❌ More complex and more expensive than incremental encoders #### Application example: #### πŸ”΅Β In robot arms to maintain the exact position of each joint even after a restart. There are also two fundamental differences in the mechanical design of rotary encoders: ### Rotary encoders with integral bearing This type of encoder has its own bearing-mounted axis to which the measuring scale is attached. #### Advantages: - The dimensional scale is precisely guided, the encoder can be precisely calibrated by the manufacturer - Simple installation in the customer application - The measuring scale and sensor system form a complete unit #### Disadvantages: ❌ Limitation of the permissible rotation speed (depending on the bearing) ❌ Use of couplings required so that no forces are transferred to the sensor bearings ❌ Relatively high overall height due to the integrated bearing ❌ Torque due to the bearing and possibly the seal ### Bearingless magnetic encoders With these rotary encoders, the measuring scale, for example the magnetic encoder, rotates freely. It is not connected to the actual sensor unit. #### Advantages: - No wear - No mechanical limitation of the rotational speed - No couplings required - Flat design - No torque - High level of integration into the application Β  #### Disadvantages: Β  ❌ The measuring scale must be aligned with the sensor unit (within certain tolerances: x-y-z, eccentricity and tilt). ### Rotary encoder technologies Different sensor technologies are used depending on the measuring principle: - Optical rotary encoders: The movement is detectedusing a light source and a coded disk - precise, but sensitive to dust and dirt. - Magnetic encoders work with Hall sensors or magnetoresistive sensors - more robust than optical variants, ideal for harsh environments and compact in design. - Inductive encoders are based on electromagnetic induction - insensitive to magnetic interference fields. - Capacitive encoders use electric fields for measurement - robust and durable, but complex in design. #### Which technology is the best? The choice of technology depends entirely on the application. Optical encoders are ideal for high-precision applications, while magnetic and inductive variants are preferredfor use in harsh environments. #### Selection criteria for the right encoder When choosing an encoder for a specific application, there are several factors to consider must be considered: - Resolution - How many distinguishable positions per revolution are required? - Ambient conditions - Temperature, humidity, dust exposure - Measuring accuracy - Is relative or absolute position detection required? - Installation conditions - How much space is available? How should the encoder and the measuring scale be mounted? - Interface and protocols - Compatibility with existing control systems (e.g. [CANopen](https://www.contelec.ch/produkte/technologien/canopen), [IO-Link](https://www.contelec.ch/en/products/technologies/io-link-system), SSI, SPI, [SENT](https://www.contelec.ch/en/products/technologies/sent), analog) Tip: Contelec offers a wide range of customized encoder solutions - absolute measuring and incremental, magnetic and inductive, singleturn and multiturn. ## Why Contelec? Contelec stands for high-precision encoder solutions that are based on state-of-the-art, continuously developed sensor technologies: - Customized solutions from prototype to series production - Highest precision: Swiss-made sensor technology for industrial applications - Flexibility and individualization: Customizable encoders for specific requirements - Reliability and durability: Developed for demanding applications Whether highly precise angle measurement or a robust encoder solution for extreme conditions - Contelec offers the optimum solution for every application. Conclusion: Encoders as key components for modern control systems Encoders are essential components for the precise control of machines and processes. Whether incremental or absolute, inductive or magnetic - the right choice of sensor depends on the requirements of the application. With customized solutions and innovative technology, Contelec offers the perfect encoder technology for all individual requirements. [βœ…](https://www.contelec.ch/kontakt)Β [Contact us now - Let our experts advise you!](https://news.contelec.ch/contact?hsLang=en) [Roger Zingg ](https://news.contelec.ch/funktionale-sicherheit/author/roger-zingg)Roger Zingg has been Managing Director of Contelec AG, a company based in Biel, Switzerland, which specializes in the development and production of angle sensors, since 1989. Under his leadership, Contelec has established itself as a leading provider of sensor solutions used in various industries such as agricultural engineering, medical technology and the energy sector. With over 35 years of experience in the sensor industry and a strong commitment to sporting activities, Roger Zingg embodies a balance between professional success and personal passion. Translated with DeepL.com (free version) ## RELATED ARTICLES ```json { "@context" : "https://schema.org", "@type" : "Organization", "address" : { "@type" : "PostalAddress", "addressCountry" : "", "addressLocality" : "Biel/Bienne", "addressRegion" : "Schweiz", "postalCode" : "2503", "streetAddress" : "Portstrasse 38" }, "knowsLanguage" : "en", "logo" : { "@type" : "ImageObject", "url" : "https://144894419.fs1.hubspotusercontent-eu1.net/hubfs/144894419/logo_309x802pixel.png" }, "name" : "Contelec AG", "url" : "https://news.contelec.ch/funktionale-sicherheit/what-is-a-rotary-encoder" } ``` ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "abstract" : "Find out how encoders detect and control precise movements in industrial automation and mechanical engineering, and what technologies and applications are available.", "author" : { "@type" : "Person", "name" : "Roger Zingg" }, "dateModified" : "", "datePublished" : "", "headline" : "What is a rotary encoder and how does it work?", "image" : "https://144894419.fs1.hubspotusercontent-eu1.net/hubfs/144894419/drehgeber.jpeg", "inLanguage" : "en", "keywords" : "[Functional Safety]", "mainEntityOfPage" : { "@type" : "WebPage" }, "name" : "What is a rotary encoder and how does it work?", "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://144894419.fs1.hubspotusercontent-eu1.net/hubfs/144894419/logo_309x802pixel.png" }, "name" : "Contelec AG" }, "text" : "Rotary encoders, also known as angle sensors, angle encoders or encoders, are indispensable components in industrial automation, mechanical engineering and many other technical applications. They enable the precise measurement of rotary movements and positions. Machines can thus be efficiently controlled and monitored. What is a rotary encoder? A rotary encoder is a sensor that converts the rotary movement of an axis into an electrical signal. This signal can be used by control systems to precisely record the position, speed or direction of a movement, position, speed or direction of a movement. Rotary encoders are crucial for automated systems in many applications. They enable precise and reliable acquisition of movement data. Areas of application for rotary encoders: Industrial automation: Position control of robots, machine control Vehicle technology: Steering angle detection, engine control, pedal position Medical technology: Precision control in diagnostic devices, surgical robots Renewable energies: Speed and blade angle monitoring of wind turbines How does a rotary encoder work? Rotary encoders typically consist of three components: The measuring body can consist of a magnetic encoder or an encoder disk, for example, and is connected to the rotating axis of the machine. The sensor system detects the movement and converts it into an electrical signal. The electronic interface transmits the signals to a controller or a display. The function of rotary encoders is based on various measuring principles, which are divided into two main categories: Incremental encoders Functionality: An incremental encoder generates a certain number of pulses per revolution. By counting these pulses, the speed or relative position can be determined. Advantages: High resolution possible Simple design and cost efficiency Ideally suited for speed detection Disadvantages: No absolute value (position is lost in the event of a power failure) Application example: πŸ”΅ In CNC machines for detecting the speed of a spindle Absolute rotary encoder Functionality: Absolute encoders measure the exact angular position of an axis and output this as a digital value. They are available in singleturn (measures position in one revolution) or multiturn (measures position and number of revolutions)versions. Advantages: Saves position even after a power failure Direct angle measurement possible Greater safety thanks to exact position data Disadvantages: ❌ More complex and more expensive than incremental encoders Application example: πŸ”΅ In robot arms to maintain the exact position of each joint even after a restart. There are also two fundamental differences in the mechanical design of rotary encoders: Rotary encoders with integral bearing This type of encoder has its own bearing-mounted axis to which the measuring scale is attached. Advantages: The dimensional scale is precisely guided, the encoder can be precisely calibrated by the manufacturer Simple installation in the customer application The measuring scale and sensor system form a complete unit Disadvantages: ❌ Limitation of the permissible rotation speed (depending on the bearing) ❌ Use of couplings required so that no forces are transferred to the sensor bearings ❌ Relatively high overall height due to the integrated bearing ❌ Torque due to the bearing and possibly the seal Bearingless magnetic encoders With these rotary encoders, the measuring scale, for example the magnetic encoder, rotates freely. It is not connected to the actual sensor unit. Advantages: No wear No mechanical limitation of the rotational speed No couplings required Flat design No torque High level of integration into the application Disadvantages: ❌ The measuring scale must be aligned with the sensor unit (within certain tolerances: x-y-z, eccentricity and tilt). Rotary encoder technologies Different sensor technologies are used depending on the measuring principle: Optical rotary encoders: The movement is detectedusing a light source and a coded disk - precise, but sensitive to dust and dirt. Magnetic encoders work with Hall sensors or magnetoresistive sensors - more robust than optical variants, ideal for harsh environments and compact in design. Inductive encoders are based on electromagnetic induction - insensitive to magnetic interference fields. Capacitive encoders use electric fields for measurement - robust and durable, but complex in design. Which technology is the best? The choice of technology depends entirely on the application. Optical encoders are ideal for high-precision applications, while magnetic and inductive variants are preferredfor use in harsh environments. Selection criteria for the right encoder When choosing an encoder for a specific application, there are several factors to consider must be considered: Resolution - How many distinguishable positions per revolution are required? Ambient conditions - Temperature, humidity, dust exposure Measuring accuracy - Is relative or absolute position detection required? Installation conditions - How much space is available? How should the encoder and the measuring scale be mounted? Interface and protocols - Compatibility with existing control systems (e.g. CANopen, IO-Link, SSI, SPI, SENT, analog) Tip: Contelec offers a wide range of customized encoder solutions - absolute measuring and incremental, magnetic and inductive, singleturn and multiturn. Why Contelec? Contelec stands for high-precision encoder solutions that are based on state-of-the-art, continuously developed sensor technologies: Customized solutions from prototype to series production Highest precision: Swiss-made sensor technology for industrial applications Flexibility and individualization: Customizable encoders for specific requirements Reliability and durability: Developed for demanding applications Whether highly precise angle measurement or a robust encoder solution for extreme conditions - Contelec offers the optimum solution for every application. Conclusion: Encoders as key components for modern control systems Encoders are essential components for the precise control of machines and processes. Whether incremental or absolute, inductive or magnetic - the right choice of sensor depends on the requirements of the application. With customized solutions and innovative technology, Contelec offers the perfect encoder technology for all individual requirements. βœ… Contact us now - Let our experts advise you!", "url" : "https://news.contelec.ch/funktionale-sicherheit/what-is-a-rotary-encoder", "wordCount" : "3048" } ``` ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Roger Zingg", "url" : "https://news.contelec.ch/funktionale-sicherheit/author/roger-zingg" }, "dateModified" : "2025-08-21T06:30:06.236Z", "datePublished" : "2025-08-21T06:30:00.000Z", "headline" : "What is a rotary encoder and how does it work?", "image" : [ "https://news.contelec.ch/hubfs/drehgeber.jpeg" ], "mainEntityOfPage" : { "@id" : "https://news.contelec.ch/funktionale-sicherheit/what-is-a-rotary-encoder", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://news.contelec.ch/hubfs/logo_309x802pixel.png" } } } ```