Digital Caliper with PSoC

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Anonymous
Not applicable

Hi everybody,

   

I try to develop digital caliper with PSoC instead of ASIC. As you know digital caliper use capacitance change for measure the displacement.

   

First i use TI FDC1004(capasitance to digital converter) for observe capacitance change but i can't get clear results. After that i decide to use

   

PSoC for produce PWM's for input and measure capacitance change. Any body help me how can i use PSoC for capacitance measurement ?

   

Here is the good page for understand how does digital caliper work.

   

http://electronics.stackexchange.com/questions/6713/how-does-an-electronic-caliper-work

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1 Solution
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

The magnitude of the C you want to address is important. If its large simple

   

ways to measure C with a current source and ramp the C to a V and time

   

that Q = C x V, I = C x dV/dT, C = ( I x dT) / dV.

   

 

   

If the C is quite small, a few pF to 10's of pF, a ac bridge approach may be more

   

appropriate to measure Z and compute C from that.

   

 

   

Regards, Dana.

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3 Replies
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

What is -

   

1) Range of C you have to measure

   

2) Resolution of measurement

   

3) Accuracy desired

   

 

   

Regards, Dana.

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Anonymous
Not applicable

I plan 0.5 mm resolution, but accuracy is not my first duty. First i will observe capacitance change, second with change of capasitance, i measure distance. After these steps, i think about accuracy

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

The magnitude of the C you want to address is important. If its large simple

   

ways to measure C with a current source and ramp the C to a V and time

   

that Q = C x V, I = C x dV/dT, C = ( I x dT) / dV.

   

 

   

If the C is quite small, a few pF to 10's of pF, a ac bridge approach may be more

   

appropriate to measure Z and compute C from that.

   

 

   

Regards, Dana.

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