FDC1004: Implementation of a cylindirc capacitor

Hi,

We have received your question. Let me review your information and get back to you a couple of days.

Regards

Sharath.

Hi Sarath,

No problem. I will wait your answer.

Thank you very much for your attention.

Regards,

Juan Pablo

Hi 

Did you get a chance to read the app note regarding the Immersive Straw Approach? This document gives you an overview of using the FDC1004 for liquid level sensing 

Regards

Sharath.

Yes, I read it.

The problem is different:
1) The electrodes are cylindrical.
2) The tank is metallic and is not connected to the measurement system, so I suspect that any contact with it could generate capacitive couplings with GND and therefore affect the measurement or even introduce noise in GND if GND is the electrode external capacitor. I would like to know how I can isolate the external capacitances in this configuration.

Hi,

Having a cylindrical electrode is not an issue if the capacitance value is within the specified range (+- 15pf). It might be difficult to shield the electrode with the setup you have shown. Unfortunately, FDC1004 might not be ideal for the solution you are trying to implement. It is a good idea to actually test your setup with an EVM to measure liquid levels using the measurements. We have not tried with a setup similar to yours to have an idea about the results. 

Regards

Sharath.

Hi Sharath,

And what do you recommend to measure the capacitance of the cylindrical capacitor if the FDC1004 is not suitable?

If there is no other technique, I should change the sensor.

Regards,

Juan Pablo

Hi,

I would first try with an EVM and take measurements to see if the results are satisfactory. Trying out with the actual sensor would be the best option before changing the sensor.

Regards

Sharath.

Hi,

Thanks for the help.

Regard,

Juan Pablo.