Cyclo-Voltammetry example project not giving expected results

Hi Eyals, we are working on something with the Cyclo voltammetry. However, we cannot read the data from sensor by using terminal program (RealTerm) can I ask what program you are using to get the char and do you need to modify any code in it to make the program work? our program tells us that it fails to read the SP and PC vector tables and there is no value that is stored in to the variable

Hi!
RealTerm seems to work fine for me with no code modification, although I have encountered someone asking the same question as yours previously in the forum. I would try to look it up...

After playing with the parameters I managed to reach the following graph:

This was done by raising the voltage by a constant 0.32 V and reducing the current by a constant of 5 uA.

Here are the new parameters:

My questions are:

1) why aren't my parameters in line with the alleged parameters? 

2) What may cause the constant bias (both in voltage and current measures)?

3) How can I overcome the gaps before the peaks, i.e force the current values to overlap at the ends of the voltage sweep? I assume they have something to do with some sort of selective bias, but I'm having trouble putting my finger on it...

Thanks a lot!   

Thank you. We found the solution to that problem. You can tell your friend too that using any example for Digital Die and then pass the not working code into that example and add all the library needed in. After that, it will run well. In short, the code is fine but we need to change its location. 

Hi,

Could you please increase the sample delay and ramp duration and check:

pRampCfg->RampDuration = 10*1000; /* Total duration of ramp signal. unit is ms. */
pRampCfg->SampleDelay = 2.0f; /* Time between update DAC and ADC sample. Unit is ms. */

Thanks for your response!

I've tried multiple combinations of the specified parameters, all of which affect the shape of the graph but still no luck with matching the alleged stacture.

basically I calculated the average of the distance between the edges of the shape, and then subtracted it from the increasing part of the ramp and added it to the decreasing part of the ramp (so I can "sew" the edges together). by this I got the following:

Meaning, I'm still getting the skew in the X-axis and still unable to explain the bias added/subtracted to the current respectively...

Hi,

May I know if you have checked by varying pRampCfg->SampleDelay because enough time must be give for ADC to sample and convert the settled current input at each sampling instant.

Hi again!

Thanks for your patience! Increasing the sample delay did the trick.

this is the output for 50 ms delay:

I would like to further ask though - 

1) Is the current skew between the graphs also configurable or is it, by this point, a matter of statistical  bias?

2) Is there a way to smooth the graph?

thank you!

Making progress!

by increasing the RTIA to 1 KOhm I managed to smooth the graph. still working on the skew...

Hello,

I want to know how to increase the value of RTIA.