- An incremental encoder is a type of encoder device that converts angular motion or position of a shaft into an analog or digital code to identify position or motion.
- An incremental encoder is the most widely used of all rotary encoders due to its low cost and ability to provide signals that can be easily interpreted to provide motion-related information such as velocity or change in position.
- An incremental encoder provides excellent speed and distance feedback.
- An incremental encoder can measure the change in position but not the absolute position.
- The absolute encoder output indicates the current position of the shaft whereas an Incremental Encoder output provides the data regarding the motion of the shaft which can be data related to speed, distance, and position.
Working of Incremental Encoder
- The incremental encoder working principle is, that it works by changing the shaft’s angular position into a pulse or digital signal through an optical disk.
- For every revolution, several pulses are generated where every pulse is an increment related to the defined resolution.
- Every time an incremental encoder is switched on the pulse is counted from zero, this means that the position is not stored and a ‘reset or reference’ position must be obtained before the encoder begins counting again. This is the main difference between an absolute and an incremental encoder.
- The output can be a single line of pulses (an “A” channel) or two lines of pulses (an “A” and “B” channel) that are offset to determine rotation.
- In an incremental optical encoder, the typical assembly consists of a spindle assembly, PCB, and cover. The PCB contains a sensor array that creates just two primary signals for position and speed. For an incremental optical encoder, an optical sensor detects light as it passes through a marked disc. The disc moves as the spindle assembly rotate and the information is translated into pulses by the PCB.
Specifications of Incremental Encoder
- Operating voltage ranges from 5V to 24V.
- Pulse is 500 P/R.
- The output waveform is a Square wave.
- Slew speed is 6000 RPM.
- The diameter of the shaft is 4mm.
- Body diameter is 25mm.
Incremental Encoders vs Absolute Encoders
- Absolute Encoders work in situations where accuracy for both speed and position, fail tolerance, and interoperability matters more than system simplicity. The absolute encoder can “know where it is” about its position in case of system power-down and restart if the encoder were to move during a power-down.
- The absolute encoder itself understands the positioning information – it doesn’t need to rely on outside electronics to provide a baseline index for the encoder position.
Applications of Incremental Encoder
- X and Y Indication system
- Testing Machine
- CNC Machine
- Labeling Machine
- Medical Equipment
- Drilling Machine
- Motor Feedback
An Incremental Encoder is designed to be versatile and customizable to fit a wide variety of applications. The three broad categories of applications based on the environment
- Heavy Duty demanding environment with a high probability of contaminants and moisture, higher temperature, shock, and vibration requirements as seen in pulp, paper, steel, and wood mills.
- Industrial Duty general factory operating environment which requires standard IP ratings, moderate
shock, vibration, and temperature specs as seen in food and beverage, textile, and generally factory automation plants.
- Light Duty/Servo controlled environment with high accuracy and temperature requirements such as robotics, electronics, and Assembling machine semiconductors.