SLYA048B March   2020  – June 2021 FDC1004 , FDC1004-Q1 , FDC2112 , FDC2112-Q1 , FDC2114 , FDC2114-Q1 , FDC2212 , FDC2212-Q1 , FDC2214 , FDC2214-Q1 , LDC0851 , LDC1001 , LDC1041 , LDC1051 , LDC1101 , LDC1312 , LDC1312-Q1 , LDC1314 , LDC1314-Q1 , LDC1612 , LDC1612-Q1 , LDC1614 , LDC1614-Q1 , LDC2112 , LDC2114 , LDC3114 , LDC3114-Q1

 

  1.   Trademarks
  2. 1Inductive and Capacitive Theory of Operation
    1. 1.1 Inductive Sensing Theory of Operation
    2. 1.2 Capacitive Sensing Theory of Operation
  3. 2FDC: Capacitive Level Sensing
    1. 2.1 Capacitive Technology Benefits in Liquid Level Sensing
    2. 2.2 Getting Started With Capacitive Liquid Level Sensing
    3. 2.3 Device Selection
    4. 2.4 Design Challenges and Additional Collateral
  4. 3LDC: Inductive Touch Buttons
    1. 3.1 Inductive Technology Benefits in Buttons
    2. 3.2 Getting Started With Inductive Buttons
    3. 3.3 Device Selection
    4. 3.4 Design Challenges and Additional Collateral
  5. 4LDC: Incremental Encoder and Event Counting
    1. 4.1 Inductive Technology Benefits in Incremental Encoders
    2. 4.2 Getting Started With an Inductive Incremental Encoder
    3. 4.3 Device Recommendations
    4. 4.4 Design Challenges and Additional Collateral
  6. 5LDC: Metal Proximity Sensor
    1. 5.1 Inductive Technology Benefits in Metal Proximity Detection
    2. 5.2 Criteria to Consider when Choosing Inductive Sensing for Metal Proximity Applications
      1. 5.2.1 Metal Target Movement in Relation to Inductive Coil
      2. 5.2.2 Sensing Distance
      3. 5.2.3 Size and Shape of Metal Target
      4. 5.2.4 Speed (Sample Rate versus Resolution)
      5. 5.2.5 Environmental Compensation
    3. 5.3 Getting Started With Inductive Metal Proximity Sensing
    4. 5.4 Device Recommendations
    5. 5.5 Design Challenges and Additional Collateral
  7. 6Revision History

5.2.1 Metal Target Movement in Relation to Inductive Coil

In general, movements in the z-axis (axial sensing) allow for higher sensitivity than those in the x and y-axis.

As far as the shape of the coil is concerned, a circular coil is recommended since it provides the highest Q factor for a given sized inductor. For applications that only allow for a smaller coil due to space constraints, a rectangular coil can be introduced, but will have tradeoffs such as sensing distance.

GUID-79015226-30F1-4831-BB58-A2C2CB459D89-low.pngFigure 5-3 Inductive Sensing Target Movement Topologies

For more information on sensor and coil design for the various sensing topologies, visit the LDC Sensor Design application report.