PMOD IA impedance analyzer

[AnasMu]

Hello everyone, I'm actually working on impedance measurment , i choosed PMOD IA with arduino UNO , i've read all it's component's datasheet ( AD5933 AGD849 ...) i do understand every part of it , i used the code and libraries form the web site below, bu it stil not working , actualy the part i dont undersand well is first of all how calibrate it ? ( i tryed what is noted everywhere but it didin't work ) may any one tell me in details what  should do ? i'll be very grathful and thankful :) for your help,at second , at the header of the folder ad5933-test.ino may any on te me what is REF-RESIST ? 

 

 

 

https://github.com/mjmeli/arduino-ad5933

[jpeyron]

Hi @AnasMu,

Welcome to the forums! Here is a forum thread where a community member was able to get all of the functions working correctly with a Raspberry Pi 3 Model B . They also posted some helpful setup and usage hints as well as their code(unverified). I haven't worked with the PmodIA but I do know that there are specific calibration ranges in reference to impedance that the community member goes through as well.  I believe that REF-RESIST refers to reference resistance.

thank you,

Jon

[AnasMu]

hello  dear jon 

after calibrating PMOD IA and measuring with high precision different impedance from 100ohm til 10M ohm using a frequency sweep , i need now to use low frequencies so i need to load an external clock , the problem is that i dont have time neither the oscillators suggested on the ad5933 schematic , so i use an exernal clock SI351 programmed as the PMOD IA with ARDUNO UNO , did anyone havean idea about how to connect it to the board PMOD IA ( just wire part that  need) normally it should be connected to the back of the card but the pins are with no numbers so i dont know which one is MCLK ... 

thank you so much for valuable time and consideration 

[JColvin]

Hi @AnasMu,

If you are referring to the Pmod IA, the I2C clock pins are located on header J1 (labeled as SCL), just below the single pin on header J2.

If you are instead referring to the Si5351 (such as this one from Adafruit), none of us here are familiar with that particular chip, but based on the pinout page, it looks like it has three generated clock outputs available on the 3 normal 100 mill spaced pins. The three sets of the triple pads at the top are loading spots for SMA connectors that you can add yourself. The output clock (if you are using it as a I2C clock) can be connected to the SCL pin on the Pmod IA.

Let me know if you have any questions about this.

Thanks,
JColvin

[JColvin]

Hi @AnasMu,

Just realized I misunderstood your question. The clock output on IC4 that you would want to connect your external clock to is pin 3. I have attached an image of where this is located on the bottom of the Pmod IA below. Naturally, you will also want to connect the grounds between the Si5351 and the Pmod IA (available on header J1 or on pin 2 in the unloaded IC4).

Additionally, you will encounter some difficulty running a continuous frequency sweep over the range you specified as per the AD5933 datasheet (more details on this on page 17).

Let me know if you have any questions about this.

Thanks,
JColvin

[flaviaR]

Hello @AnasMu I'm working with Pmod ia and arduino too. Could I please get in touch with you to ask you some questions? It's for my final year diploma so it's very importat.