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LDC1101: ldc1101

Raja Sharma
Prodigy 90 points
Part Number: LDC1101
Other Parts Discussed in Thread: LDC1312, LDC1612

Hello,

how can i measure the thickness of metal of MS range 1 mm to 12 mm. what should be design of sensor and and what are the parameter should set in LDC1101 like frequency nad other things.

  • 0
    TI__Genius 17440 points

    Hello,

    I don't recommend using the LDC devices to measure metal thickness directly. The eddy currents form on the surface of the target, and additional target thickness beyond the depth of the eddy currents will not change the target response. Depending on your application, you may be able to have a single target that moves closer to and farther from the sensor depending on the thickness of the material below it (see the diagram below for an example). I recommend starting with the LDC FAQ linked below.

    Best Regards,

  • 0 in reply to Kristin Jones93
    Prodigy 90 points

    Hello Kristin Jones

    thanks for your reply 

    actually my purpose is different.

    i want to measure the crack in the metal (and that thing i m doing with MFL Technology) in a pipeline.

    my purpose is that , crack is inner side or outer side in pipe line. can you suggest any other way to measure it .

    thanks 

    raja sharma

  • 0 in reply to Kristin Jones93
    Prodigy 90 points

    can you please tell me the main uses of LDC1101

  • 0 in reply to Kristin Jones93
    Prodigy 90 points

    and saw in many article that 

    Noncontact Thickness Measurement of Metal Films Using Eddy-Current Sensors Immune to Distance Variation

  • 0 in reply to Raja Sharma
    TI__Genius 17440 points

    Hello Raja,

    The primary use of the LDC1101 is for metal proximity detection. It may be possible to use inductive sensing for your application, but not the LDC1101. The LDC1101 has a minimum sensor frequency of 1MHz, and at this frequency the eddy currents would be concentrated at the surface of the metal. You would need to use a lower frequency sensor, so the LDC1312 or the LDC1612 would be more suitable.

    Please note that we have not supported this application before, so while we can provide general advice about sensor design, we don't have specific advice for this application.

    Best Regards,

  • 0 in reply to Kristin Jones93
    Prodigy 90 points

    Hello

    i see many article for high penetration depth for crack detection and eddy current testing.

    but don't get how much frequency should i take for 12mm pipeline material depth from this LC sensor.

  • 0 in reply to Raja Sharma
    Prodigy 90 points

    Above you suggest two LDC IC both has minimum LC frequency 1 KHz , my metal is MS grade 70, for that metal, this sensor is capable to penetrate to 12 mm ?

  • 0 in reply to Raja Sharma
    TI__Genius 17440 points

    Hi Raja,

    The depth of the eddy currents is based on the skin depth, which is affected by the sensor frequency and the conductivity of your target. You can calculate this with the equation in section 2.2 of LDC Target Design.

    Best Regards,

  • 0 in reply to Kristin Jones93
    Prodigy 90 points

    Thanks for this advice.

    i found skin depth in micro millimeter, Now i simply want proximity distance measurement. i did't find any sensor or IC which can penetrate up to 12mm.   

    can u please tell me what should be the sensor frequency for metal distance measurement. it has range 500kHz to 10 MHz. How can i calculate for which frequency should i take. i want to measure now only distance of metal. if any metal loss inside the pipe in inner side, sensor will measure it using distance measurement. 

    QUESTIONS?

    1. For sensor frequency setting , should  it be set by physical inductor and capacitor or it will be done by setting in IC registers.

       

  • 0 in reply to Raja Sharma
    TI__Genius 17440 points

    Hi Raja,

    For metal proximity measurements, you want all of the possible eddy currents to form in your target. We recommend that the target is at least 3 skin depths thick. Since you already have a known target, you can reverse this math to find your minimum sensor frequency.

    The resonant frequency is set by the physical inductor and capacitor. The LDC device automatically drives the LC tank at its resonant frequency.

    Best Regards,