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FDC1004: Please help understand how to use the GUI v1.9.4 and FDC1004evm

Janine Lin
Expert 2190 points
Part Number: FDC1004

Dear TI

Please help me understand how to use this GUI v1.9.4 , I am stuck here.  In the datasheet, it says that starting the measurement configuration i have to set the input channel in GUI and choose what type of measurement (either single-ended or differential). Does this fdc1004 evm consider as differential? If so, what to set in the Channel measurement? What these means CAPDAC, offset capacitance and gain, measured sensor data?

 

What does delta and standard deviation in statistics mean?

and this?

  • 0
    TI__Expert 6625 points
    Hi Janine,
    Please refer to sections 8.3.2, 8.3.3 and 8.3.4 of the datasheet: www.ti.com/.../fdc1004.pdf, for explanation on CAPDAC, offset capacitance and gain. After reading about these parameters, you can change these values in the GUI as you see fit for your application. Please refer to our FDC1004 EVM user's guide on how to use the GUI: www.ti.com/.../snau163c.pdf. Delta is the difference between the max and min values measured. Standard deviation is the one sigma deviation from the mean value. Graph configuration can be used to change up how the data is plotted, you can vary the time for samples collected, change the vertical axis and so on. You can also download the data as an excel file from the data streaming tab and plot the data yourself.

    Best Regards,
    Bala Ravi
  • 0 in reply to Bala Ravi
    Expert 2190 points

    Thank you Bala. 

    I have another question. The data shown below is the test result for a single ended configuration by using our own sensor (size 2.5cm, 0.4 cm thickness).

    The target is aluminum with a thickness of 1.5cm, dimension is 3cm x 3cm. You said, to determine its sensing range the delta between them is 10 times the noise floor. What do you mean by this?

    Results below,   

    - mean value without target is (1.35 CpF), Delta is 0.038

    - at 1 cm value with target is (1.829 CpF), Delta is 0.104

            

                             

    This is how we connect our sensor. Shield 1 and shield 2 are shorted. Cin connects to Sensor electrode. 

  • 0 in reply to Janine Lin
    TI__Expert 6625 points
    Hi Janine,
    What I meant to say was without target, the delta measurement can be considered as your noise floor. Then the delta with target needs to be 10x greater than the noise floor. From your results it looks like the delta is only 3x the noise floor. You can either do one of the following: 1. Make a bigger sensor, 2. Decrease the target distance. Or you could do both which is also good.

    Best Regards,
    Bala Ravi

    Please click "This resolved my issue" button if this post answers your question