LDC1614EVM: Measuring metal

Patrick O'Neill

Part Number: LDC1614EVM

Hello,

My question is two-fold:

Assuming a planar, circular coil is being used as the sensor, if a metal target (let's assume a small sphere of metal 1mm in diameter) is within the sensing region, is the LDC161x series "better" at measuring:

The proximity of the metal object,
The movement of the metal object through the field, or
The quantity/size of the metal object(s) in the field

AND

Is the LDC better at picking up certain types of metal than others? I.e. should metal with a higher conductivity be sought after, or would responses be better with magnetic/paramagnetic materials?

Thanks!

Patrick

over 3 years ago

+1 Justin Beigel over 3 years ago

TI__Mastermind 18545 points

Hello Patrick,

For a high level introduction into how our LDC devices work, please see https://training.ti.com/overview-inductive-sensing-technology. The LDC161x couple to a metal target through the magnetic field generated by the sensor coil. Because of this, they work best determining the proximity of flat metal targets. With a sphere, you would see a change in the measurement whether the sphere moves laterally to the sensor or across it but the amount of data change you see as the sphere moves across the sensor would be determined by how far away the sphere is. As for determining the quantity/size, you do have a slight impact here but it would not work as well as proximity sensing. For more information on target size impacts, please see: https://e2e.ti.com/blogs_/b/analogwire/posts/inductive-sensing-target-size-matters.

In regards to metal types, metals with a higher conductivity provide a better response. Whether the material is magnetic or not does not impact the sensor performance as it is immune to DC fields. A couple good resources that touch on target properties are LDC Target Design (Rev. B) and Inductive Sensing for LDC3114 Metal Proximity Detection.

Best Regards,

Justin Beigel

Sensors

Sensors forum

LDC1614EVM: Measuring metal