FDC2214 EVM setting for differential sensor configuration...

Peter Tseng

Other Parts Discussed in Thread: FDC2214

Dears,

My customer want to test FDC2214 with diff. sensor.

How to set the correct setting in EVM GUI while using diff. sensor?

Another question is, customer feedback the result they got(pF) is too small, no matter small or big PCB sensor they used.

Is there any method to get the larger value?

Thanks.

over 9 years ago

0 Yibo Yu over 9 years ago

TI__Expert 8050 points

Hello,

Please set CHx_FIN_SEL (where x can be 0 to 3) according to Table 1 in the datasheet.

The measurement result would depend on what the customer is measuring and their sensor and system configurations.

Best regards,
Yibo

0 Peter Tseng over 9 years ago in reply to Yibo Yu

Mastermind 6260 points

My customer want to measure the soil moisture.
As I know, the bigger sensor we used, the larger result difference we will get.
About the system configuration, what can I adjust to get larger difference value of result?
Thanks.

0 Yibo Yu over 9 years ago in reply to Peter Tseng

TI__Expert 8050 points

Hi Peter,

Bigger sensors should always give larger capacitance values, since capacitance is proportional to the area of the sensor if everything else is constant.

The challenging part of this application is that the capacitance change due to soil moisture change is probably very small. Does your customer has an estimate of how much capacitance change they are expecting to measure?

Thanks,

Yibo

0 Peter Tseng over 9 years ago in reply to Yibo Yu

Mastermind 6260 points

Hi Yibo,

After checked with customer, they hope to get around 100pF difference from Max. and Min. capacitance.
How about your suggestion for such requirement?
BTW, is there any design guide of sensor for FDC products?
Thanks.