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Encoders Provide Motor Speed and Position Control

August 31, 2021

How Encoders Provide Motor Speed and Position Control 

In many mechanical systems, precise motion hinges upon effective monitoring and control of the motor. Encoders make motion control possible by sensing the motor’s speed and position and sending feedback signals to control components. Two square waves, or channels, shifted 90 electrical degrees from each other, along with an optional index pulse that occurs once per revolution, encode the angular position data. 

Where You’ll Find Encoders 

Here is just a small sample of the many applications that incorporate encoders: 

  • Drug delivery systems. During a pump’s development process, feedback helps determine the motor speed needed to deliver the proper amount of medication.
  • Automated window shades. The mechanism that provides automatic speed and position control incorporates an encoder. Console settings are developed based on the motor speed requirement to move the shade into the desired position.
  • Electronic assembly equipment. Motors used in electronic assembly operate in sync, relying on encoder feedback to ensure that all varying components are picked up and placed on the circuit board simultaneously.
  • Robotics. Varying speeds and pressures are required for robotic grippers. Encoders help engineers understand motor speed and position of grippers to create accurate motion profiles. 

Optical and Magnetic Encoder Benefits 

Portescap offers two popular encoder types: optical and magnetic encoders. Each type offers designers many features and benefits. Examples include: 

  • Incremental Optical Encoders. A dedicated ASIC, composed of optoelectronic sensors, receives infrared (IR) light emitted from an LED and passed through a metal disc — known as a codewheel — with both opaque and clear segments in order to provide very precise positioning without sensitivity to external magnetic fields.
  • M2 Magnetic Encoder. Using an integrated magnetoresistive sensor to provide sin/cosine magnetic field measurements, this encoder is not affected by temperature and exhibits a low sensitivity to unwanted external fields. Resolution up to 512 lines is available.
  • M-sense Magnetic Encoder. This compact encoder uses just a single chip to provide three channels of feedback, and includes an RS-422 line driver. Resolution ranges from one to 1,024 lines per revolution.‘

Encoder Feedback Ensures Precise Motor Control 

Designers of motor-driven systems have come to rely on encoders to provide feedback in response to motor speed as well as the direction and position of the rotor. This feedback is used to develop control systems for the final product. Portescap offers robust optical and magnetic encoders that stand up to severe environments and can deliver resolutions from four to 1,024 lines per revolution, with up to three channels. 

For more information about Portescap encoders, download the complete white paper or visit our product page.