HALL EFFECT SENSING AND APPLICATION MICRO SWITCH Sensing and Control 7DEOHRI&RQWHQWV Chapter 1 • Hall Effect Sensing Introduction ................................................................................................................................ 1 Hall Effect Sensors..................................................................................................................... 1 Why use the Hall Effect .............................................................................................................. 2 Using this Manual....................................................................................................................... 2 Chapter 2 • Hall Effect Sensors Introduction ................................................................................................................................ 3 Theory of the Hall Effect ............................................................................................................. 3 Basic Hall effect sensors ............................................................................................................ 4 Analog output sensors................................................................................................................ 5 Output vs. power supply characteristics ..................................................................................... 5 Transfer Function ....................................................................................................................... 6 Digital output sensors................................................................................................................. 7 Transfer Function ....................................................................................................................... 7 Power Supply Characteristics..................................................................................................... 8 Input Characteristics .............................................................................................................................. 8 Output Characteristics............................................................................................................................ 8 Summary.................................................................................................................................... 8 Chapter 3 • Magnetic Considerations Magnetic Fields .......................................................................................................................... 9 Magnetic materials and their specifications ................................................................................ 9 Basic magnetic design considerations...................................................................................... 10 Magnetic materials summary.................................................................................................... 11 Magnetic systems..................................................................................................................... 11 Unipolar head-on mode ............................................................................................................ 12 Unipolar slide-by mode............................................................................................................. 12 Bipolar slide-by mode............................................................................................................... 13 Bipolar slide by mode (ring magnet) ................................................................................................... 14 Systems with pole pieces ..................................................................................................................... 15 Systems with bias magnets................................................................................................................... 16 Magnetic systems comparison ................................................................................................. 17 Ratiometric Linear Hall effect sensors ...................................................................................... 18 Summary.................................................................................................................................. 18 For application help: call 1-800-537-6945 Honeywell • MICRO SWITCH Sensing and Control i Table of Contents Chapter 4 • Electrical Considerations Introduction .............................................................................................................................. 19 Digital output sensors............................................................................................................... 19 Electrical specifications........................................................................................................................20 Specification definitions............................................................................................................ 20 Absolute Maximum Ratings.................................................................................................................20 Rated Electrical Characteristics............................................................................................................21 Basic interfaces........................................................................................................................ 21 Pull-up resistors ....................................................................................................................... 21 Logic gate interfaces.............................................................................................................................22 Transistor interfaces .............................................................................................................................22 Symbols for design calculations ............................................................................................... 24 Analog Output Sensors ............................................................................................................ 29 Electrical specifications........................................................................................................................30 Basic interfaces.....................................................................................................................................30 Interfaces to common components .......................................................................................... 31 Summary.................................................................................................................................. 32 Chapter 5 • Hall-based Sensing Devices Introduction .............................................................................................................................. 33 Vane-operated position sensors............................................................................................... 33 Principles of Operation.........................................................................................................................33 Sensor Specifications............................................................................................................................35 Digital current sensors.............................................................................................................. 36 Principles of Operation.........................................................................................................................37 Sensor Specifications............................................................................................................................37 Linear current sensors.............................................................................................................. 38 Principles of Operation.........................................................................................................................38 C.losed Loop Current Sensors ................................................................................................. 39 Principles of Operation.........................................................................................................................39 Mechanically operated solid state switches.............................................................................. 41 Principles of Operation.........................................................................................................................41 Switch specifications ................................................................................................................ 42 Gear Tooth Sensors................................................................................................................. 42 Principles of Operation.........................................................................................................................43 Target Design........................................................................................................................... 43 Summary.................................................................................................................................. 44 Chapter 6 • Applying Hall-effect Sensing Devices General sensing device design ................................................................................................ 45 Design of Hall effect-based sensing devices ............................................................................ 47 System definition.....................................................................................................................