Explore the Different Types of Rotary Encoders

Rotary encoders have become important components in various industries for the purpose of providing position, speed and direction feedback of rotating machinery and systems. They are widely used in fields such as automation, robotics, aerospace and manufacturing. With their precision and accuracy, rotary encoders enable precise control and monitoring in numerous applications.

There are two main types of rotary encoders: incremental and absolute. While both function similarly, there are differences in how they work and what they do to provide feedback. In this article, we will explore these different types of rotary encoders and focus on the main differences between incremental and absolute encoders.

Incremental encoders, also known as relative or quadrature encoders, provide incremental readings of rotation, indicating changes in position and velocity. They generate an output signal in the form of pulses. Each pulse represents a specific increment of motion. The number of pulses produced per revolution is called the resolution of the encoder. These pulses are usually sent to a counter or PLC, which converts them into useful information such as speed, distance or position.

A significant advantage of incremental encoders is their simplicity and cost-effectiveness. They are relatively easier to implement and less expensive than absolute encoders. Additionally, incremental encoders do not require a reference point to determine absolute position. They can start counting from any point in the rotation cycle, which makes them suitable for applications requiring continuous motion, such as conveyor belts or motor control.

However, incremental encoders have a significant limitation. They do not provide absolute position feedback. In the event of a power outage or system reset, incremental encoders cannot track absolute position, only relative motion after reset. This limitation makes them less suitable for applications requiring precise positioning and absolute accuracy.

Absolute encoders, on the other hand, provide precise absolute position feedback. These encoders generate a unique output code for each index position or increment in their rotational cycle. This code represents the exact position of the encoder shaft at any given moment. Unlike incremental encoders, absolute encoders do not require a reference point to determine absolute position.

The advantage of absolute encoders is that they retain position information even in the event of a power loss or system reset. This feature makes them ideal for applications where precise positioning is critical, such as CNC machine tools, robotic arms, or medical equipment. Absolute encoders also offer higher resolution and greater accuracy than incremental encoders.

However, the cost and complexity of absolute encoders is high. Implementing an absolute encoder requires additional circuitry and decoding mechanisms to interpret the output codes. Also, unlike incremental encoders, absolute encoders cannot directly determine the speed or distance of rotation. These parameters need to be calculated based on location information over a period of time.

In summary, both incremental and absolute encoders play a vital role in various industries, providing the necessary feedback for controlling and monitoring rotating machinery. The choice between these two types depends on the specific requirements of each application. Incremental encoders are simple and cost-effective for continuous rotation applications. Absolute encoders, on the other hand, provide precise absolute position feedback and are ideal for applications where precise positioning is critical. Understanding the differences between these types of rotary encoders is critical to selecting the most appropriate encoder for each specific use case.