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LDC1612: Proximity of multiple sensing coils

Ashley Foxcroft
Prodigy 20 points
Part Number: LDC1612
Other Parts Discussed in Thread: LDC1614

I intend to create an array of inductive sensors covering a surface.

Assuming the sensor coils have the same diameter and are operating at the same frequency, how much separation is needed (if any), to prevent measurement problems due magnetic field interaction?

It does not matter if adjacent sensors detect the same target (if the target is between sensors), it only matters if close proximity of sensor coils causes malfunction, significant loss of accuracy or reduction of measurement distance.

If I imagine the field lines around a Coil, I would guess that there would need to be a gap (from OD to OD) equal to at least twice the coil diameter, but for my application a smaller gap equal to the coil diameter would be preferred. I intend to experiment but any advice would be helpful.

Thanks

  • 0
    TI__Genius 13650 points

    Hello Ashley,
    a keep-out area around the coils certainly helps, especially if the coils are active at the same time. Devices such as LDC1612/LDC1614 are multiplexed and operate in a round-robin activation scheme, so only one of the coils is active at any time. If only one coil is driven at any time, the keepout area can be smaller.
    Since the coils are on the same plane, the sensing range is smaller than coils that are arranged on parallel planes. We don't have a specific rule for keepouts around the coils because it depends on accuracy requirements and on whether or not there other coils in the same array are driven, but 1/2 coil diameter is appropriate for most applications.