Incremental vs Absolute Encoders: Signal Output Classification and Applications

Signal Output Classification of Incremental and Absolute Encoders

Encoders are essential components in industrial automation, widely used for measuring parameters such as angle, speed, and position. When classified by signal output, incremental and absolute encoders are two common types, each with significant differences in working principles and signal outputs. In this article, we will explore the differences between these two types of encoders and their applicable use cases.

Signal Output Classification of Incremental Encoders

Incremental encoders transmit position changes via a series of pulse signals, with each pulse representing a small incremental movement. These encoders typically output two signals, A and B, which are orthogonal (90-degree phase-shifted) signals, enabling precise measurement of rotation direction and speed. The main features of incremental encoders are:

• Simplicity and Cost-Effectiveness: Incremental encoders are designed to be simple and cost-effective, suitable for applications where high precision is not critical.

• Pulse Output: Position changes are tracked by the number of pulses output, making them ideal for applications requiring relative position measurements.

• Need for External Reference: Incremental encoders cannot retain position data after power loss or system reset, requiring external devices or reference signals to restore the initial position.

Common Applications: Assembly lines, robotic control, CNC machines, etc.

Signal Output Classification of Absolute Encoders

Unlike incremental encoders, absolute encoders provide a unique signal output for each position, ensuring that position data is preserved even after a power loss or system restart. Absolute encoders often use multiple output signals, with each bit representing a different level of position information. Common signal types include:

• Parallel Output: Multiple digital signal lines are used to output position data, with each bit representing a different level of the encoder’s position.

• Serial Output: Serial buses (e.g., SSI, Modbus, CAN) are used to transmit position data, making them suitable for long-distance transmission and multi-channel applications.

• Multi-Turn Absolute: Some advanced absolute encoders can measure multiple rotations, offering highly precise position data, ideal for applications requiring high-precision positioning.

The main advantage of absolute encoders is their ability to retain position information without the need for external devices, making them crucial in applications that demand high reliability and accuracy.

Common Applications: High-precision machinery, aerospace, robotics, automated control systems, etc.

Choosing Between Incremental and Absolute Encoders

When considering the signal output classification, incremental and absolute encoders serve different application needs. Choosing the right encoder type can enhance system precision and reliability. Below are some guidelines to help with the selection:

• Choose Incremental Encoders: If your application only needs to measure relative position changes and does not require absolute position data, with a focus on cost and simplicity, incremental encoders are the ideal choice.

• Choose Absolute Encoders: If your application requires precise, absolute position data, and you prioritize system reliability and accuracy, absolute encoders are better suited, especially for high-end automation and precision instruments.

Understanding the differences between incremental and absolute encoders in terms of signal output classification can help you make an informed decision about which encoder type best suits your needs, ultimately improving the performance and reliability of your system.

Conclusion

Whether it’s an incremental encoder or an absolute encoder, each type offers distinct advantages and is suitable for different applications. Selecting the right encoder based on signal output classification can improve system efficiency and reduce maintenance costs. Understanding the working principles and output classifications of these encoders is crucial when making a decision. We hope this article helps you better understand the characteristics of incremental and absolute encoders, enabling you to make an informed choice.