• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 414 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

Original question:

LDC2112: Sensor stack up.

LDC2112: No target applications.

Alex Wu2
Intellectual 260 points
Part Number: LDC2112


Hi Kristin

1. I have a new design and the coil pattern will become larger. Is it do not need a target? because of my inductance very strong about 5.7uH. The external key is plastic. Can it be triggered with a finger click plastic button?

2. If the target still needs to be retained, the middle of the target is hollowed out, Din is about 6.4mm. The LED can shine through the middle and the external key is plastic. Hollowed out the target of the middle can be triggered by pressing the key? I'm afraid it cannot detect the deflection.

3. Could you share no target application?

Thank you.

Orange color is hollow out the target of the middle and covers to the coil.

New design DL:24mm Dout:12mm Din:6.4mm

  • 0
    TI__Genius 17440 points

    Hi Alex,

    1. No, inductive sensing always requires a metal target.

    2. No, the sensor will likely not be able to detect this target. The eddy currents that form on the target are a mirror image of the sensor coil. If there is a hole in the target above the coil, then the eddy currents will not be able to form there and the target response will be greatly reduced. In addition, the largest target deflection is at the center of the button, so the target movement (and therefore inductive response) would be minimized by removing the central area.

    3. There are no applications where there is never a metal target over the sensor. However, there are some applications that need to detect the presence or absence of a metal target. For example, some factory automation customers may wish to detect when a metal sheet is in front of a sensor and when there is no metal present at all. In this case they would need to know the sensor coil's characteristics with and without the target present.

    Best Regards,

  • 0 in reply to Kristin Jones93
    Intellectual 260 points

    Hi Kristin

    1. Which design is recommended? If A and B both are not workable, is there any spec of hole size on the target pattern or it can’t accept any tiny hole?

    2. Target Metal Plate is flat but the plastic housing outside is a curve. Would this kind of design impact on sensor's function or sensitivity?

    3. You suggest aluminum for target, the aluminum of any series is OK? I can use only the aluminum suggested by the form 6061-T6 and 1100? Our ME wants to use aluminum 5052. Is it suitable?

    Thank you.

    The blue section is the metal target.

    The yellow racetrack is the sensor coil.

  • 0 in reply to Alex Wu2
    TI__Genius 17440 points

    Hello Alex,

    1. We don't recommend any gaps or holes in the metal target because they disrupt the eddy currents. In addition, we recommend that the coil turns fill the central area of the coil for button applications.

    2. This will affect the mechanical response of the button. Thicker housings may require more force to activate the button, and thinner housings may require less force. This would also depend on the material used, so unfortunately I can't definitively say what effect this would have. You will need to test this.

    3. The most important aspect of the target material is the conductivity. If aluminum 5052 has similar conductivity as the aluminum suggested in the tool, then it would be suitable. 

    Best Regards,