Quantum Devices Incremental Optical Rotary Encoders

Incremental Optical Rotary Encoder Basics

Incremental optical rotary encoders, also known as shaft encoders, are electromechanical position feedback devices. The output data they generate provides information to control systems and allows them to determine position, speed, acceleration, deceleration and travel distance in motion control applications.

An optical encoder consists of the following components: a moveable disc, an LED (Light Emitting Diode) source, a photo detector and a signal processor that converts the analog waveforms to digital waveforms.

The encoder disc, or code wheel, has a pattern of spaces, called windows, on it. When the LED light passes through one side of the disc, the photodiode detects interruptions. The photodiode creates analog signals which are processed and digitized for use by external control devices.

What are Incremental Optical Rotary Encoders Used For?

Industrial and commercial applications that use optical rotary encoders include:

Aerospace & Defense
Automated Guided Vehicles (AGV)
Autonomous Mobile Robots (AMR)
Conveyor Applications
Elevators
Factory Automation
Galvanometer Scanners
Industrial Controls
Medical Devices
Off-Highway Vehicles
Oil & Gas
Passenger Rail
Pulp & Paper Mills
Robotics
Rotating Radar Platforms
Servo Motors
Steel Mills
Stepper Motors
String Potentiometers
Wood Processing

Learn more about optical encoder applications or contact us for help selecting the best encoder for your specific project.

Rotary Encoders

Rotary encoders, also known as shaft encoders or transmissive rotary encoders, are electromechanical position feedback devices. The output data they generate provides information to control systems and allows them to determine position, speed, acceleration, deceleration, and travel distance in motion control applications.

They’re called rotary encoders because they measure how far something turns (like a servo motor shaft). This measurement of distance around an axis is called angular position.

Incremental Encoders

An incremental encoder is a type of rotary encoder that indicates motion and direction. Incremental encoders work by generating A/B output signals based on a specific number of pulses per rotation. In this way, the angular motion of the shaft is converted into a code (encoded) to determine its position or motion.

Incremental encoders provide information about rotary motor speed and distance. They’re commonly used for industrial motion control applications.

Rotary Encoders: Incremental vs. Absolute

An incremental rotary encoder is different from an absolute rotary encoder in the type of information it measures. Incremental encoders measure change in position. Absolute encoders indicate the absolute position, which is a designated starting point. Because the absolute or “zero” position of the shaft is recorded, an absolute encoder provides position data even after a power failure, or if the shaft moves while the encoder is turned off. Incremental encoders require a reset or reference position every time they’re turned on, to locate their position in rotation.

Optical Encoders

An optical encoder is a type of rotary encoder that uses an LED light source, a photodetector (light sensor), and a moveable disc with slotted openings to generate and count light pulses as the shaft turns. Optical encoders are used to measure position, velocity, and acceleration in a variety of applications.

Optical rotary encoders are extremely precise and offer higher resolution (accuracy), making them ideal for applications like machine tools, robotics and CMMs (coordinate measuring machines).

If you’d like to learn more, dive into the technical details behind how optical encoders work or explore: