SNOAA04A March   2020  – June 2021 FDC1004 , FDC1004-Q1 , FDC2112 , FDC2112-Q1 , FDC2114 , FDC2114-Q1 , FDC2212 , FDC2212-Q1 , FDC2214 , FDC2214-Q1 , LDC0851 , LDC1041 , LDC1051 , LDC1101 , LDC1312 , LDC1312-Q1 , LDC1314 , LDC1314-Q1 , LDC1612 , LDC1612-Q1 , LDC1614 , LDC1614-Q1 , LDC2112 , LDC2114 , LDC3114 , LDC3114-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Inductive Sensor Simulation
  4. 3Using the Electromagnetic Problem Answer File
  5. 4Calculating Resolution
  6. 5Other Resources
  7. 6Summary
  8. 7References
  9. 8Revision History

Using the Electromagnetic Problem Answer File

  1. Open the .ans file
    1. The .ans file will generate in the same directory as the .FEM file. Open the .ans file.
    2. Note that if any changes are made to the .FEM file, solving the problem again will overwrite the .ans file.
    3. The .ans file should show the magnetic field lines, which should bend around the target. The outer boundaries represent a gradient to infinity, so the magnetic field lines may contort in this region. Only the region contained by the innermost boundary line is of interest.
      GUID-ED7D3EEA-859C-4EF9-ACE3-19979A144341-low.gif Figure 3-1 Axisymmetric Answer File Showing the Contour Plot of the Magnetic Field Around the Coil and the Target
  1. Change the contour plot options
    1. Navigate to View → Contour Plot, or click on the Contour Plot button GUID-4189B439-7583-4079-B820-D52788B923EE-low.gif
    2. In the Contour Plot Options, change the number of contour lines, as well as their upper and lower bounds, and click OK.
      GUID-5D125AB5-F7B0-4053-A587-CF2455F9E621-low.gif Figure 3-2 Contour Plot Options Menu
  2. Add various density plots
    1. Navigate to View → Density Plot, or click on the Density Plot button GUID-A63D7F0B-B5DB-40EA-8BC0-756431B43AB4-low.gif
    2. In the Dialog menu, check the Show Density Plot box.
    3. Select the desired Plotted Value, generally |Flux Density| (T) or |Current Density| (MA/m2). Flux density is useful for determining optimal target placement, because we want the target in the area of highest flux density. Current density is useful for displaying eddy currents.
      GUID-C6E5511A-A912-4970-AA7B-EDBF2F5AF9D9-low.gif Figure 3-3 Axisymmetric Answer File Showing Flux Density Plot
      GUID-7BA1EDCD-CF0D-4F21-8D0F-BD4A989ACBF3-low.gif Figure 3-4 Axisymmetric Answer File Showing Current Density Plot That Shows Eddy Currents on the Target
  3. Change the mesh
    The mesh is one of the most important aspects in generating an accurate answer file. Generally, it is best to choose a small mesh around the coils, the target, and the axis of symmetry (for axisymmetric problems).
    1. To display the mesh, navigate to View → Show Mesh, or click the Show Mesh button GUID-606B5BFA-80C6-4E58-B28A-9F87E45C95FF-low.gif
    2. To change the mesh, return to the .FEM file.
    3. To select the desired material, click the green materials button GUID-48A7AA2B-0F75-4BF5-9B00-F6931D34056C-low.gif then right-click near the desired material node and press the space bar. The Properties for selected block menu should open.
    4. Uncheck the Let Triangle choose Mesh Size box.
    5. Enter a new Mesh size. A mesh size around 0.01 is a good starting point. Note that the problem must be solved again to reflect any changes.
  4. View the inductance of the coil
    1. Click the Inductor button GUID-36623B4A-E4BF-48BF-9BB4-55D38DCD4C0F-low.gif at the top.
    2. The Circuit Properties menu should open. The inductance will be listed as Flux/Current.
      GUID-38B12951-90E1-4457-9360-1BBF7B7E6941-low.gif Figure 3-5 Circuit Properties Menu