Incremental Rotary Encoder


An incremental rotary encoder is a type of electromechanical device that translates the rotational movement of an object into digital signals. It generates a series of electrical pulses, also known as counts, for each incremental movement. Unlike an absolute rotary encoder, it does not provide an absolute position but measures relative changes in position, requiring the use of a reference point to track the overall rotation.


“Incremental Rotary Encoder” in International Phonetic Alphabet (IPA) can be represented as:/ˌɪnkrɪˈmɛntəl ˈroʊtəri ɛnˈkoʊdər/Each syllable can be broken down as:- ˌɪn: in- krɪ: cre- ˈmɛn: men- təl: tal- ˈroʊ: ro- tə: ta- ri: ry- ɛn: en- ˈkoʊ: co- dər: der

Key Takeaways

  1. An Incremental Rotary Encoder is an electromechanical device that converts the angular position or motion of a shaft to a series of digital pulses.
  2. Unlike an absolute encoder, an incremental encoder provides only relative position data, which means it requires a known reference point or a home position to determine the absolute position.
  3. Incremental Rotary Encoders are commonly used for speed control, direction sensing, and position tracking in various applications such as robotics, CNC machines and other automation systems.


The term “Incremental Rotary Encoder” is important in technology as it refers to a vital electromechanical device that converts the angular position or motion of a shaft or axle to an analog or digital code.

This process enables precise monitoring and control of mechanical systems, such as robotics, motors, and other automated equipment.

Incremental rotary encoders differ from absolute encoders by providing relative position data, which means they register the change in position rather than the absolute position.

This makes them cost-effective, simple to implement, and highly reliable for various applications, including industrial automation, motion control systems, and measurement devices.

The significance of an incremental rotary encoder lies in its ability to enhance the performance, efficiency, and accuracy of numerous technological systems.


Incremental rotary encoders serve as essential components in various industries and applications that demand precise positional feedback or require the monitoring of rotational movements. For instance, they play a crucial role in the automation industry, motor control systems, robotics, and even in everyday devices like computer mice and CNC machines.

These encoders convert rotational motion into digital signals, which allow control systems to accurately track specific movements, thereby ensuring the precision and effectiveness of the operations being performed. An incremental rotary encoder works by generating a series of pulses in response to the rotations; these pulses are then interpreted by a connected controller to regulate speed, displacement, or positioning.

The encoder consists of a rotating disc with a set of specialized patterns usually made of opaque and transparent segments to create an alternation. As the disc rotates, an LED emits light that passes through or is blocked by these segments, resulting in a pulse train output.

The number of pulses corresponds to the angular displacement of the rotating disc, enabling the connected system to monitor and control operations effectively. Incremental rotary encoders are valued for their simplicity, cost-effectiveness, and versatility, which make them ideal for a wide range of applications.

Examples of Incremental Rotary Encoder

Robotic Arms: Incremental rotary encoders are used in robotic arms to track the angular position and speed of each joint. By attaching an incremental encoder to each joint, the robot’s control system can precisely control the position and motion of the arm. This level of accuracy allows a robotic arm to perform tasks like assembly, welding, or even delicate tasks like surgery.

Conveyor Belt Systems: In an industrial setting, incremental rotary encoders are often used to monitor the speed and movement of conveyor belts. By continuously measuring the rotation of a conveyor belt’s roller, the encoder sends signals to the control system, which can then adjust the belt’s speed, direction, or position as needed. This ensures that products move efficiently and accurately throughout the manufacturing, packaging, or warehousing processes.

Wind Turbines: In wind energy generation, incremental rotary encoders are employed to measure the rotational speed of the turbine blades. By accurately monitoring the wind turbine’s speed and position, the control system can optimize the angles of the blades and generator performance, thus ensuring optimal power generation and reducing the chance of damages caused by excessive wind speeds or adverse weather conditions.

Incremental Rotary Encoder FAQ

What is an Incremental Rotary Encoder?

An Incremental Rotary Encoder is an electromechanical device that converts the angular position or motion of a shaft or axle to an analog or digital output signal. These encoders provide incremental, or relative, position information, which means they report the change in position rather than the absolute position.

How does an Incremental Rotary Encoder work?

An Incremental Rotary Encoder consists of a disc with evenly spaced markings that interrupt a light source as they rotate. This interruption generates a series of electrical impulses, which are counted by an encoder counter. The counter measures the number of electrical impulses to determine the change in position or motion.

What are the common applications of Incremental Rotary Encoders?

Incremental Rotary Encoders are commonly used in industrial automation systems, robotics, machine tools, and other applications requiring precise control of motion and speed. They help in monitoring and controlling position, velocity, and acceleration in various applications like CNC machines, motors, conveyor belts, and robotics.

What are the advantages of using an Incremental Rotary Encoder?

Incremental Rotary Encoders offer several advantages, including their high resolution, rapid response time, and simple design. They are cost-effective, easy to install, and typically have a long service life. Incremental encoders are also immune to power loss, as they do not require a power source to retain position information.

What is the difference between Incremental and Absolute Rotary Encoders?

The primary difference between Incremental and Absolute Rotary Encoders lies in the information they provide. Incremental Encoders produce relative position information, meaning they report the change in position. In contrast, Absolute Encoders generate unique codes for each position, allowing them to provide absolute position information. Incremental Encoders are typically less expensive and faster, while Absolute Encoders provide more precise positioning and are better suited for applications where position information must be retained after power loss.

Related Technology Terms

  • Optical Disc
  • Quadrature Signals
  • Pulses per Revolution (PPR)
  • Index Pulse
  • Interface Circuit

Sources for More Information


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