• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 32 subscribers
  • Views 750 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LDC 16xx

Syed Mansoor Shah
Prodigy 20 points

I am considering LDC 16xx to use for measuring lift off from and speed of a moving target. I would like to know if that could be done if

1) Target is a carbon steel material is under the influence of a magnetic field.

2) The lift off from the sensing coil would be in the range of 0 - 8 mm

3) There could be some debris (metallic and non-metallic)

4) The carbon steel target is moving at speed from 5 feet/ minute to 200 feet / minute and accurate speed measurement is required.

5) can one channel play dual role of distance measurement as well as the lift off measurement?

I need to evaluate this component for my application. Is there any evaluation kit available?

  • 0
    TI__Genius 14270 points
    Hello Syed,

    Please look for the evaluation module at www.ti.com/.../LDC1612EVM.

    Please clarify your question on lift-off. I assume it means the sensor coil is no longer in contact with the target. It is generally OK for the sensor to be in contact with the target, as long as the RP of the sensor does not drop too low.

    In response to your questions:
    1) Carbon steel will work fine with the LDC161x, as long as the sensor frequency is high enough. Typically, a sensor frequency >300kHz will work fine with steel.
    2) This can be addressed with a coil of 8mm diameter or larger. The larger sizes may be necessary depending on the resolution requirements.
    3) The non-metallic debris should not pose an issue. As for the metallic debris, it depends on the quantity; a small amount should not be an issue.
    4) What is the interval of time over which you need to measure the speed/position? For the LDC161x on its most accurate setting, you would be able to make a single channel measurement every 40ms; this would correspond to a position shift of ~1inch.
    5) Yes, although using two channels can help compensate for temperature effects.

    Regards,

    ChrisO
  • 0 in reply to Chris Oberhauser66
    Prodigy 20 points
    Thanks for the reply Chris,
    I bought the LDC 1614 EVM. I found some interesting feature that I would like to share. I installed the evaluation software, and then connected the board with my computer and observe the coils inductance. I noticed that when ever I touch the coil or press it with a minimal force in my fingers, the inductance changes by ~1.5 uH. The target is a carbon-steel cylindrical pipe. I need to measure the lift of with and accuracy of +-0.005 inches.
    I used the coil on the board that I guess has the diameter of 14mm. I used the capacitor setting of 200pF and the Rate = 10ms on the EVM software. I used the plastic gaps of .184" and .185". If I measure the inductance very carefully, I get the difference of 0.002uH. But the actual inductance reading vary from 0.100uH to 0.5uH. I don't have any clue how to make the inductance reading more stable.
  • 0 in reply to Syed Mansoor Shah
    TI__Genius 13650 points

    Hi Syed,

    what you are observing when touching the coil is a capacitive effect (see question "When I touch the sensor coil, the GUI shows an increase in inductance. Why?" on the Inductive sensing FAQ