new use for LDC1000

Gaylord Olson

What would be the smallest diameter coil that can be used with the LDC1000?

Is it practical to consider using an analog MUX to combine 2 coils on the LDC1000 device to sense more than one location?

Can differential coils be used to sense the difference for a more exact measurement?

over 11 years ago

0 Evgeny Fomin over 11 years ago

TI__Genius 9300 points

What would be the smallest diameter coil that can be used with the LDC1000?

-Please see FAQ: http://e2e.ti.com/support/data_converters/inductive-sensing/f/938/t/295036.aspx#Q2

Is it practical to consider using an analog MUX to combine 2 coils on the LDC1000 device to sense more than one location?

-Yes. The tradeoff is reduced data rate.

Can differential coils be used to sense the difference for a more exact measurement?

-Could you please elaborate on this? you might need to add an extra coil in series, if total inductance of the differential coils becomes insufficient to meet Rp requirements.

0 Gaylord Olson over 11 years ago in reply to Evgeny Fomin

Prodigy 25 points

Evgeny, I looked at FAQ question 2 as you suggested, but it does not show coil diameter.

Also, regarding differential measurements, it seems that with two coils multiplexed into one LDC1000 a more precise measurement could be done because any temperature drift in either the coils or the electronics would be largely removed. I assume that a metal target motion perpendicular to the coil axes is to be measured. Has this been done?

0 Evgeny Fomin over 11 years ago in reply to Gaylord Olson

TI__Genius 9300 points

Hello,

I'm sorry for the confusion, we have updated the FAQ q2, please take a look again.

In short, there is no simple answer to your question (please see the explanation there). It greatly depends on the coil design/parameters.

Indeed, what you have described is one of the ways to deal with temperature variation. Please see the app note http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=snaa212&fileType=pdf for more details.

Yes, it has been done for a very similar applications.

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new use for LDC1000