Absolute Optical Encoder: Precision Position Feedback for Modern Automation

An absolute optical encoder is a high-precision sensor that provides unique digital position data for every shaft angle, making it a cornerstone of advanced motion control and automation systems. Unlike incremental encoders, which only track changes in position, absolute optical encoders deliver the exact position immediately upon power-up—eliminating the need for homing routines and ensuring reliable, repeatable performance in critical applications.

How Does an Absolute Optical Encoder Work?

At the heart of an absolute optical encoder is a code disc with concentric tracks, each etched with a unique pattern of transparent and opaque segments. As the shaft rotates, a light source (typically an LED) shines through the disc. Photodetectors on the opposite side read the light patterns, which are then converted into a unique binary code representing the precise angular position of the shaft. This code is transmitted digitally to the control system, providing instant and unambiguous position feedback.

Key Components:

· Optical Code Disc: Marked with a non-repeating binary or Gray code pattern.

· LED Light Source: Illuminates the code disc.

· Photodetectors: Capture the light passing through the disc to generate digital signals.

· Signal Processing Electronics: Convert optical signals into digital position data.

Types of Absolute Optical Encoders

· Single-Turn Absolute Encoders: Provide a unique code for each position within one revolution of the shaft. Ideal for applications where the shaft does not rotate more than 360°.

· Multi-Turn Absolute Encoders: Track both the position within a single turn and the total number of revolutions, using additional mechanical or electronic counting mechanisms. Essential for applications requiring extended range or multi-axis positioning.

Advantages of Absolute Optical Encoders

· True Position Feedback: Delivers the exact position immediately after power-up, even after power loss—no need for re-homing.

· High Resolution and Accuracy: Optical technology enables resolutions up to 23 bits (over 8 million positions per revolution) and absolute positioning accuracy within ±50 angular seconds.

· Noise Immunity: Digital output is less susceptible to electrical noise, ensuring reliable operation in industrial environments.

· Non-Volatile Memory: Retains position data without external power, making it ideal for safety-critical and mission-critical systems.

Typical Applications

Absolute optical encoders are widely used in:

· Servo Motor Feedback: Providing precise position and speed data for servo-driven control systems in robotics, CNC machines, and industrial automation.

· Medical Equipment: Ensuring accurate positioning in imaging and diagnostic devices.

· Aerospace and Defense: Delivering reliable feedback in navigation and stabilization systems.

· Material Handling: Enabling precise control of conveyors, lifts, and automated storage systems.

Our absolute optical encoders, such as the RZ series and RZ35 series bearing models, are specifically designed for servo motor applications. These products showcase the advanced features and reliability of modern absolute optical encoder technology. Their main features are:

· Resolution: 17 to 23 bits (131,072 to 8,388,608 positions per revolution)

· Multi-Turn Capability: 16-bit counter (up to 65,536 revolutions)

· Operating Temperature: -20°C to +105°C

· High-Speed Operation: Up to 6000 rpm

· Robust Communication: RS485 interface, 2.5 MHz baud rate

· Mechanical Durability: Withstands shock, vibration, and harsh industrial conditions.

An absolute optical encoder is the preferred choice for applications demanding high accuracy, reliability, and instant position feedback. Its advanced optical sensing technology, combined with robust digital output, makes it indispensable in modern automation, robotics, and precision machinery.

For more information on selecting the right absolute optical encoder for your application, or to learn about the RZ35 Series, contact our technical team today.