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Using electrodes with ADuCM350 4 Wire BioZ board

Question asked by Majo on May 2, 2016
Latest reply on May 13, 2016 by emoloney
Branched from an earlier discussion

Hi Eoghan,

 

I would like to ask you for advice.

I do not know if I am doing again something wrong.

Today I wanted to try measure with 4 electrodes system.

I found on the analog device site (4Wire-Isolated-Bioimpedance ADuCM350 Connections To Sensor), that when I want to measure with 4 electrodes I have to remove all links besides (LK7 - LK10) and all R_access resistors. So, I did this. I put the wires on that places and I connected the AD8226 as is pictured in pdf (http://www.analog.com/media/en/technical-documentation/application-notes/AN-1302.pdf - page 14 to 15).

The measured output is different that I expected. When I increase the frequency the impedance is increasing. And I also tried to measure the output from AFE8 with oscilloscope and I am not able to measure anything. Maybe the measured impedance is therefore wrong because there is no output or lots of noise.

 

Thanks in advance

 

Best regards

Marian

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