Post Go back to editing

3 electrode EIS measurement using AD5940 EVAL ELCZ

Thread Summary

The user is performing EIS measurements on a 3-electrode system using the AD5940 EVAL ELCZ board and is experiencing phase values outside the expected range of 0 to -90 degrees. The final answer suggests tuning the HSRTIA (Internal RTIA Selection) and ADC PGA gain to prevent saturation and improve accuracy. The user should also ensure the differential input to the ADC is within +/-0.9V.
AI Generated Content

Hello AD Team,

I have purchased AD5940 EVAL ELCZ board 

I want to perform EIS measurement for a 3 electrode system

Working electrode - Gold

Counter electrode - Platinum 

Reference electrode- Ag/AgCl (0.21 V vs Standard Hydrogen Electrode)

Calibration settings :

frequency range: 1KHz to 10Hz

Bias voltage: 300mV vs Ag/AgCl reference electrode

In the AD5940_examples code for impedance measurement , the method used was Sense electrode connected to AINx pins which was a 2 electrode system (WE :AINx and CE: CE0)

How do I modify this code to accommodate a 3 electrode system as given above ? What should be the switch matrix configuration ?

Kindly guide me through the process