Calibration Phase

[JeanRintoul]

Hi there,
When I run Z logger I can get temperature but then it will stall. Is there something that you are supposed to do apart from press p to do calibration?

[itkwon]

Can you describe the situation more?

This program assumes people do some wiring manually. Thus, someone should change the wire before the pressing 'p' and enter.

At the first time, the user should put the calibration resistor between Vin and Vout, and press 'p' in the terminal (on Arduino) and press enter. After the calibration, press 'p' and enter after you place the actual resistor to measure.

If you can read source code, I recommend to analyze the code.

Thanks.

[JeanRintoul]

I have a 10K resistor located across Rcal and am running Z_logger. However I notice it is breaking in the function bool AD5933_Class::isValueReady() on the function getStatusReg() returning false every time. I have it set up exactly as per your diagram, supplied with 3v3 v from arduino diecimila. What does isvalueready do and how does it relate to ADC conversion as per the comment in the code?

[itkwon]

The internal (private) function isValueReady returns the signal whether the measurement and ADC conversion is completed. If isValueReady() is false, the measurement process is not completed.
Please read page 26/40 of datasheet.

I am not sure your problem. If you provide your circuit diagram, it would be helpful.

[JeanRintoul]

[JeanRintoul]

Thank you for helping. The above is my circuit diagram exactly and isvalueready is always false and never returns true.

[tunjid]

@JeanRintoul What is the ratio between Rcal and Rfb? Might not change much, but I can't guess why else. Also I notice you're using pull-up resistors for your I2C wiring. Most Arduino boards have internal pull-up resistors, so I don't think that's necessary either. We don't use ours with pull-up resistors, that may be the problem. I'm not sure, but I suggest trying it without.

[itkwon]

Sorry, I am late little. I am back from my vacation, and compared yours with mine.
I examined the diagram, but I cannot figure out what is really wrong. Also, I just figured out that the diagram is produced by TJ (@tunjid), and it works.

1. I think you can try TJ's (@tunjid) suggestion to run the circuit without pull-up resistors. In my circuit, I am using 2k ohm pull-up resistors.
2. Regardless of the value of Rcal and Rfb, the circuit might produce any result, but you can provide the value of Rcal and Rfb to track down the problem. You can try the settings in the document CN-0217.
   http://www.analog.com/static/imported-files/circuit_notes/CN0217.pdf
3. Just make sure every single component works well. Check every connection and voltage source with Multimeter. Check the breakout board and its connection with the AD5933. Make sure I2C communication works well.
4. Make sure you are using most recent source code and library. Make sure you copied my library into your Arduino library, and you do not alter any source code.
5. I am not sure it works, but taking a picture of your circuit might be helpful, too.

[barrybelmont]

Hello Jean.

Did you ever get this working?

[itkwon]

Did you test I2C communication between the chip?