SLYA060 August   2022 TMAG5110 , TMAG5110-Q1 , TMAG5111 , TMAG5111-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1 Introduction
  4. 2 System Block Diagram
  5. 3 Key System Specifications
  6. 4 HW Connections
  7. 5 Software
    1. 5.1 TI-RSLK LaunchPad Software
    2. 5.2 LaunchPad Software
  8. 6 How to Design With Hall-Effect Latches
  9. 7 Simulation Results
    1. 7.1 Select Device Sensitivity
    2. 7.2 Select Axis of Sensitivity
  10. 8 Performance Comparison
    1. 8.1 Speed and Direction
    2. 8.2 Power Consumption
    3. 8.3 Susceptibility to External Particles
  11. 9 Encoder Board Schematic and Image
  12. 10Summary

1 Introduction

Motors can be used to harness and convert electrical energy into mechanical energy, enabling us to control the motion of components connected to them. Typically, this is done by controlling the rotation of the motor’s shaft and having external components connected so that they rotate along with it. For today’s standards, causing an external component to move is simply not enough. Many systems require detection of the external components' relative movement to extract the speed in which the module is rotating. This allows us to pass the information back to the system so that it could be refined to meet the systems requirements. Information such as speed or displacement of an object can be derived by tracking the speed of a motor shaft.

To detect the speed of each motor shaft, either an incremental or absolute encoder may be implemented. An absolute encoder can provide information on the position of the shaft itself. An incremental encoder, on the other hand, simply provides information on the incremental change in position instead of the exact position of the shaft, which is sufficient for measuring the shaft speed. Magnetic incremental encoders and optical incremental encoders are two common implementations for incremental encoding.

This document expands on some of the topics covered in the Differences Between Optical and Magnetic Incremental Encoders application brief. The breif mainly focuses on the use of incremental encoders in robotic vacuum cleaners, but encoders can be found in a vast amount of devices and across various industries. Automatic blinds, textile machines, ventilators, automotive seat position modules, and liquid flow meters are all some examples of equipment that use rotary encoders.

The following sections provide an overview on how to design with Hall-effect latches and how to setup the TI RSLK platform used for testing the magnetic and optical incremental encoders developed. There are also a test/result-based comparison near the end of this document. The test will cover the ability to measure speed of pulses, show how the system performs in a dusty environment, and lists current consumption measurements between both implementations.