What is Rotary Encoder
It is an electro-mechanical device that coverts the angular motion/position of the shaft to analog or digital code.It is also known as shaft encoder.
Application
Rotary encoders can be used in all applications that require monitoring rotation rate, speed, acceleration and direction. These sensors can be utilized in many applications found in mechanical engineering, the conveyor industry, material handling and the packaging industry. You are certain to find a suitable rotary encoder for your application from our broad product offering.
In automation, rotary encoders are used as sensors for angle, position, speed and acceleration. Linear motion can also be measured through the use of spindles, gear racks, measuring wheels or cable pulls.
Rotary encoders convert a mechanical input into electrical signals, which can be processed by counters, tachometers, programmable logic controllers and industrial PCs.
Rotary encoders in many application which require precise shaft unlimited rotation specialy in robotics,industrial control,special purpose photographic lense,computer input devices(mouse & trackballs)
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| Absolute rotary encoder ROQ 425 |
There are two types of rotary encoder :
- Absolute
- Incremental(Relative)
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| A Gray code absolute rotary encoder with 13 tracks. At the top the housing, interrupter disk, and light source can be seen; at the bottom the sensing element and support components. |
Absolute Encoder
Output of absolute encoder indicates current position of the shaft.It maintains position information when power is removed from the system and when power is again to the system the position is retrieved.
Incremental Encoder
Output of incremental encoder supplies information regarding motion of the shaft in terms of speed,distance,position.It doesn't power up with fixed relation between encoder state and position.
Use in industry
Encoders used on servomotors
Rotary encoders are often used to track the position of the motor shaft on permanent magnet brushless motors, which are commonly used on CNC machines, robots, and other industrial equipment. Incremental (Quadrature) encoders are used on Induction Motor type servomotors, but absolute encoders are used in Permanent Magnet Brushless Motors, where applicable. In these applications, the feedback device (encoder) plays a vital role in ensuring that the equipment operates properly. The encoder synchronizes the relative rotor magnet and stator winding positions to the current provided by the drive. Maximum torque results if the current is applied to the windings when the rotor magnets are in a particular position range relative to the stator windings. The motor will perform poorly or not at all if this timing is not adjusted correctly. Improper encoder alignment on the motor can actually cause it to run backwards sometimes resulting in a hazardous run away condition. Correct alignment is essential to proper operation of these motors.