LDC1000 / principle of getting resonance point

Ryuji

Guru 20090 points

Hello,

Could you please let me know the deriving method of fsensor?
I would like to know the principle.(why LDC1000 can get the resonance point.)

My understanding are the following.
-Setting the min resonance frequency.
-increment the frequency counter(sweep the signal frequency)
-searching the maximum impedance of LC circuit.Then that point is ther resonance frequency point.
-At the resonance frequency point, difference voltage between INA - INB is maximum.
-Thus, LDC1000 can get the frequency point and write the data to Frequency counter.

Best Regards,
Ryuji

over 11 years ago

0 Igor Gorbounov over 11 years ago

Expert 1070 points

Hi, Ryuji,as it has been said here in the forum previously the minimum frequency is used only for inner watchdog needs - to kick

the device when it hangs.

Best wishes,

Igor

0 Ryuji over 11 years ago in reply to Igor Gorbounov

Guru 20090 points

Hello Igor san,

I would like to know the method that LDC1000 get the Rp(d) at resonance point.
Do the Internal ADC of LDC1000 measure the difference voltage between INA and INB?

Best Regards,
Ryuji

0 Igor Gorbounov over 11 years ago in reply to Ryuji

Expert 1070 points

Hi, Ryuji,

I believe that the TI guys can give you a more accurate answer, but I suppose that (in general) this LDC1000

is measuring somehow the amount of electrical power that the LC tank absorbs, and when some conducting material
gets near the coil, this absorbtion increases.

There is a lot of semi-scientific articles devoted to eddy current measurements's applications, and in general those

interested in eddy current principles are simply sent to Maxwell equations...

Best wishes,

Igor

0 Ryuji over 11 years ago in reply to Igor Gorbounov

Guru 20090 points

Hello Igor san,

I wait the reply from TI.

And I could find the eddy current measurement articles. The article is useful for my understanding.Thank you for your advice.

Best Regards,
Ryuji

0 Evgeny Fomin over 11 years ago in reply to Ryuji

TI__Genius 9300 points

Hello Ryuji-san,

Unfortunately, we cannot disclose the information on how the resonant frequency is found - it's TI IP.

Sensors

Sensors forum

LDC1000 / principle of getting resonance point