To the moderators - I guess I am asking questions which were asked before, hopefully this is the right thread now, since my last two posts were not allowed. Let me know if I am doing something wrong.
Hi, obviosly measuring at low frequencies it is not a simple thing, but those low frequencies is exactly the area of interest of such measurements. I also have the same problem and already loose a lot of time with it.
What I am reading on the Analog website about blood coagulation application, which is quite close to mine (measure different contaminants in water) is following
"The AD5933 can measure impedance values between 100 Ω and 10 MΩ to a system accuracy of 0.5% for excitation frequencies from 1 kHz to 100 kHz"
OK, what I am using here, now, is AD5933-EVB Rev.C and generator on the board 16MHz. What I want to measure is for example 1K-10K, 10Hz to 5kHz, in steps of 10Hz. Can somebody tell me - is this possible to be done by optimising parameters or modifying Evaluation software (VB or LV), or I need to think about custom hardware/firmware/software solution or think about other way of measuring (not using AD5933 at all)? What will be "standard" setting values if I am measuring simple resistors - clock, settling time, excitation PGA, DDS, RFB?
@Patrick Lafont - can you publish Arduino code and schematics you are using? What is the lowest frequency you are able to measure at? I guess Arduino can be directly used with Pmod IA kit, and then add all the circuitry needed for specific measurement.