jamesbraza

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  1. Okay @attila, thank you for providing that script! That cleared me up. My mistake was thinking that FDwfAnalogImpedanceStatusInput returns a value with units = dB. It seems the units were actually = V/V. This is more desirable functionality. One suggestion: maybe in future Waveforms versions, specify the units of gain returned by FDwfAnalogImpedanceStatusInput in the SDK documentation. Again: thank you again for answering all of these questions!
  2. @attila okay thank you for answering all of my questions, your answers all makes sense! Also, I was not previously aware of Hungarian notation. So I implemented the code you suggested above: I ran the Impedance Status Input on a load of a 100 kΩ resistor and a 0.1 μF capacitor in series. I found the formula `gain2 - 1.0` does not match what WaveForms is outputting. Waveforms output, attached My output (gain2 - 1.0), attached These are slightly off, and I am trying to figure out why. @attila do you know if WaveForms has some compensation done internally that a raw FDwfAnalogImpedanceStatusInput would not output?
  3. Hi @attila, Thank you again for your response. I have several follow-up questions: I constantly see the prefix `rg` in your programs. What is the meaning of `rg` prefix in all array namings? Why does the gain term = V_C1 / V_C#? I would think it's the inverse... gain = output / input = V_C2 / V_C1 Does the formula you listed, M = gain2 - 1.0, come from a simplification of M = (V_C1 - V_C2) / (V_C2 - 0)? Also, please see the attached image. It's of input phase. Note sometimes the points are flipped about 360°. My final question is, do you know why this might be happening?
  4. Hello Digilent Forums, I have an Analog Discovery 2 + Impedance Analyzer board, and have been programmatically manipulating the board via the DWF library. I am now trying to plot Input Phase (∠) programmatically. The SDK for Python comes with a `dwfconstants.py`, which houses values of `c_int()`, corresponding with various measurement types. For example, `DwfAnalogImpedanceImpedance` measurement type corresponds to `c_int(0)`. I do not see a constant for Input Phase inside `dwfconstants.py`. Is it possible to get Input Phase? Thank you in advance for your help!
  5. Hello Digilent Forums, I have two question about the Impedance Analyzer and Waveforms. On the voltage plot, there is a V_RMS, V_Real, and V_Imag. My understanding of V_RMS is that it's the RMS voltage drop through the load. How does WaveForms get V_Real and V_Imag? Are these calculated values, and if yes, how are they calculated? Also, my understanding of Input Phase ∠ is it equals the phase difference between V_C2 and V_C1. Does a positive ∠ mean that V_C2 lags or leads V_C1? Thank you in advance for your help!
  6. Hi @attila, Thank you for getting back to me. I ended up writing 1:1 wrapper functions on the API methods I use that look something like this. def FDwfDeviceClose(hdwf: c_int) -> int: """Close the handle for a given device. Args: hdwf: (c_int) dwf handle Returns: int: 1 if successful, 0 if unsuccessful """ return dwf.FDwfDeviceClose(hdwf) Note: `dwf` is a global variable in this case. Cheers to AD2!
  7. Hello Digilent Forums, I am trying to write a Python script for the impedance analyzer. I am reading the WaveForms SDK and following examples. I noticed all methods in the examples that use the dwf (Ex: `dwf.FDwfDeviceOpen`) use positional arguments. In the SDK, it lists the parameter names/types for the method (Ex: `FDwfDeviceOpen(int idxDevice, HDWF *phdwf)`). I have tried and failed to figure out how to specify them using keyword arguments instead. Is it possible? Thank you in advance for your help!
  8. Hi @attila, Okay so I read Test Equity's Application Note and found the below image on pdf page 15 of Keysight's handbook. So I now understand what θ is, and also now I understand what is the point of having added all the parallel and series channels. Thank you again for your help!
  9. Thank you again for the response @attila. That `Time` view comparing the two oscilloscope's voltage measurements is quite useful! Your response has made me question my understanding of θ ("Phase") vs ∠ ("Input Phase"). To reword what you said above: ∠ = difference (°) between Phase_VC1 and Phase_VC2 What does that make θ?
  10. Hello Digilent Forums, I am a new user of the Analog Discovery 2 + Impedance Analyzer instruments. I am using WaveForms 3.10.9. I am trying to understand the metrics for Input and Phase. In the docs, `impedance.html`, it lists: Input as showing the "DUT/reference resistor". The Y axis plot is "M Input Gain" with units in dB. Phase as showing the phase angle and Ref RLC input phase. I am assuming θ ("Phase") is the phase difference seen by the Analog Discovery 2's two scopes between V and I. Can you please explain more what the terms mean? M ("M Input Gain") ∠ ("Input Phase") For your reference, I have attached a plot generated using a 100 kΩ resistor and then a 0.1 μF capacitor in series. Thank you in advance for your help!
  11. @attila @JColvin thank you for your answers! As I understand more about this software, I come to think you guys are doing something great - making impedance measurement more accessible -James Braza
  12. @JColvin thank you again for answering! I read in the other posting as well, and found it useful! Here is what I meant by my parallel vs series question: I set up my DUT to be a 100 kΩ resistor and then a 0.1 μF capacitor in series. I ran the Impedance Analyzer for a single run. I have attached a screenshot of my result, Impedance view. You can see the Xp and Xs values are very different. My thoughts are: WaveForms doesn't know what the DUT is, whether it was a parallel or series setup. All it knows is what was measured across the J2 connector's pins. However, WaveForms is reporting very different reactances for a so-called "parallel" and "series" set up. So what does WaveForms mean by Xs and Xp? Clearly it's doing some different processing to make these plots Thank you again in advance. I am going to @attila since you did so above for WaveForms questions.
  13. Okay that makes sense, thank you for your answer @JColvin The heart of my question is confusion about why we tell WaveForms this information, if In other words: What is the purpose of marking as series or parallel? Does WaveForms do additional computations with this information? What if my DUT has multiple inductors/capacitors in a network, such that they are sort of both in a series/parallel arrangement? Also, how does the use of the Element parameter tie into this? For example, what is the difference between marking `Auto` and `Capacitance`? What would happen if I have an inductor in series with a capacitor, and then marked the Element as `Capacitance`? Regardless, thank you again for your above answer.
  14. I am a new user and am trying to understand what all the knobs in this program are for. I have an Analog Discovery 2 + Impedance Analyzer board. In `impedance.html` of the documentation, it talks about series resistance/reactance and parallel resistance/reactance. However, it never actually defines what these address. The same thing goes for the Meter's parameters for series model and parallel model. What do these terms refer to? Is it some hardware configuration within the AD2? There seems to be no documentation of these terms, despite me searching through this forum. Thank you in advance for your help! -James