What’s the Difference Between Rotary and Linear Encoders?

Across many modern industrial and automation applications, signal accuracy and optimized system feedback are two crucial elements of upholding efficiency, performance, and safety. Encoders are central to these goals, serving as electromechanical devices that convert motion into electrical signals to determine position, velocity, and direction. Among the most commonly used types are rotary encoders and linear encoders, each of which presents its own set of unique characteristics and capabilities that make them suited for different applications. As such, understanding their differences is vital for making the most informed purchasing decisions.

The Role of Encoders in Automation and Control

Encoders generally work by converting physical movement into electrical signals that control systems can interpret and harness for various functions. For instance, these signals provide feedback to machinery that promotes more precise positioning and motion control, a very tangible benefit. Without encoders, many automated systems would struggle to maintain accuracy, efficiency, and repeatability in operations, all of which are necessary for the requirements of modern operations.

Encoders typically fall into two broad categories: rotary encoders, which measure angular motion, and linear encoders, which measure straight-line displacement. Both share the same principle of motion-to-signal conversion, though they are each designed for different types of measurement.

An Introduction to Rotary Encoders

Rotary encoders are designed to detect rotational movement, often being mounted on shafts to measure angular displacement, velocity, and the direction of rotation.

How Rotary Encoders Work

Rotary encoders generally use optical, magnetic, or capacitive sensing principles to function. With the spinning of a disk or ring that is attached to a rotating shaft, sensors can detect changes in light, magnetism, or capacitance. The sensors then send a signal in relation to the change, which is interpreted by the control system to determine the shaft’s position and speed.

Common Types of Rotary Encoders

• Incremental Encoders: These encoders are able to measure changes in position relative to a starting point, allowing them to provide information concerning direction and speed.
• Absolute Encoders: These encoders provide a unique digital signal for every shaft position, allowing accurate levels tracking even when power is lost.

The Applications of Rotary Encoders

• Robotics: Rotary encoders in robotics applications are often tasked with monitoring the angle of joints to uphold controlled movements.
• Industrial Motors: Industrial motors leverage rotary encoders to control speed and torque for the benefit of automated machinery.
• Elevators and Conveyors: Rotary encoders are useful for tacking rotational motion in elevators and conveyor systems to synchronize movement.
• Aerospace Systems: Measuring rotational components in navigation and control systems is made easier through the use of rotary encoders.

An Introduction to Linear Encoders

While rotary encoders handle angular motion, linear encoders are specialized for measuring linear displacement. These devices specifically detect movement along a straight path, making them indispensable in a range of applications with their high levels of accuracy.

How Linear Encoders Work

Linear encoders often operate on optical, magnetic, inductive, or capacitive sensing principles, where a scale is paired with a sensor head to detect changes as an object moves along the scale. The system then translates measurements into digital signals that represent position or displacement. Linear encoders often vary in what is used as the scale, with magnetic strips, glass grating, and other mediums all being popular.

Common Types of Linear Encoders

• Incremental Linear Encoders: These linear encoders provide relative position changes along a path, requiring a reference point for calibration.
• Absolute Linear Encoders: These linear encoders offer unique readings at each point along their path, ensuring accurate feedback even after interruptions.

The Applications of Linear Encoders

• CNC Machinery: Linear encoders are regularly employed throughout CNC machinery to uphold accuracy during cutting, milling, and drilling operations.
• Semiconductor Manufacturing: Linear encoders provide ultra-high accuracy in component placement, supporting semiconductor manufacturing.
• Medical Imaging Equipment: Medical imaging equipment may leverage linear encoders to assist in the positioning of scanners and tables.
• Metrology Tools: Metrology tools with linear encoders achieve more exact measurements in quality control and testing environments.

How Internet of Hardware Can Address Your Needs

As we have shown in this article, rotary and linear encoders both play notable roles in industrial automation, robotics, aerospace, and engineering applications. While rotary encoders measure angular displacement for shafts and motors, linear encoders provide exact measurements of straight-line movement for machinery and metrology. By understanding their differences, decision-makers and industry professionals can better match encoder technology to their operational needs, ensuring efficiency.

For organizations seeking reliable rotary or linear encoders, it is essential to source from trusted suppliers that prioritize quality and compliance. Internet of Hardware is the perfect solution with our wide range of quality-assured encoders and automation solutions, all of which are sourced from leading manufacturers and suppliers to meet the needs of demanding industrial applications. Take the time to explore our offerings at your leisure, and with our online Request for Quote (RFQ) forms, you can always kick off procurement with ease.

---

1. rooland cooper
2. Posted on October 3, 2025
aviation

---

Related Blogs