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Found 13 results

  1. Both the export data display in Waveforms and the exported CSV data are incomplete/garbled I am using the image save function as workaround , but then have to manually transfer to spreadsheet Using most current Waveforms, downloaded today. Haven't looked at analyser export function yet impedance data.csv
  2. Hello there!! I'm trying to do capacitance measurements over the time with a Analog Discovery 2 NI edition and save then, as the code on the image below. But now, I need to implement 2 things in this script, wich I would like to know if it is possible to. 1) Save the measurements acquired automatically in a file on the computer (like a .txt or anything like that) 2) Make the script change the frequency of the Impedance meter as it run ( for example, acquisition 0 to 4 runs in 10kHz and 5 to 9 runs in 5kHz) If it is possible, how could I implement that on my script ? Thanks everyone for the attencion!
  3. Hi guys, love this product, wish I had it when I was back getting my EE degree, couple of questions I don't understand what activates the warning message for load resistor too high or too low? I haven't found the guidance for what it should be - is it supposed to be some percentage of the expected impedance range? Is it meant to be a current limit? I'm measuring a small RLC network and getting both "too high" and "too low" warnings at nearly the same frequency points (2-3 each) near resonance of the circuit. That's with a 10k ohm load resistor and a network impedance that runs from 3k to 40k ohms from audio 20Hz to 20kHz. The curve looks smooth so I've mostly been ignoring it, but If my measurement is off due to the load I'd like to fix it (but don't know what to do with conflicting warnings). If I just live with the warnings can I suppress the display of the warnings, so they're not visible when I take screen captures for my presentation? Also, new topic - can I make the traces for Z, R and X different colors from each other? I only see how to change the color in a way that changes all of them to still be the same. 2nd new topic - can I change the background of the display to be white instead of the dark grey. I think I've seen some screen caps posted that were white but don't see how to change.
  4. Dear, Is it possible to build a custom graph by the Script tool? My intention is to construct a graph of the imaginary part versus the real part of the impedance. Thanks in advance for your attention. Cleber Borges
  5. Hello I want to purchase a PmodIA board for some impedance analysis on batteries. I was wondering if I could connect the Pmod IA to an arduino to carry out the testing. Thank-you
  6. Notes and questions on impedance function Observations 1) Impedance function/capability not listed on the AD2 Data sheet 2) AD2 data sheet shows only one channel voltmeter "Single channel voltmeter (AC, DC, ±25V) Network analyzer – Bode, Nyquist, Nichols transfer diagrams of a circuit. Range: 1Hz to 10MHz" Questions 3) Online manual for the impedance function does not cover use with the BNC adapter "Selectable AC and DC coupling to oscilloscope probes Selectable 50-ohm or 0-ohm output impedance on arbitrary waveform generator (AWG) channels" 3a) Only DC coupling is shown in the Impedance application selection boxes , so the adapter jumpers should be set that way ? 3b) Should output impedance jumper be set to 50 ohm to match BNC cables, 0 ohms or does the compensation function make it irrelevant ? 4) There is a drop down menu in the application in Wavforms that I did not see explained in the online Impedance application manual "Element " with choices Auto, Inductance , Capacitance and "Model " with choices Series, Parallel. What are these functions ?
  7. Hello, I'm using the pattern generator with the output type set to open drain when the output is Z, measuring the output impedance I read almost 5K Ohm, What could be the problem?
  8. Hello to everyone. I recently purchased an pmodIA board for a project we are conducting at work. The main goal is to obtain some resistivity vs frequency spectra for different objects as part of a object characterization problem involving Oil/Gas stuff. I already read the guide that digilent guys provide (http://store.digilentinc.com/pmod-ia-impedance-analyzer/) and I found some C libraries for the AD5933 (https://github.com/analogdevicesinc/no-OS/blob/master/Pmods/PmodIA/AD5933.c and https://github.com/analogdevicesinc/no-OS/blob/master/drivers/AD5933/AD5933.c). I am using a Raspberry Pi 3 Model B to control & communicate with the pmodIA. I based my code on those C libraries I mentioned. In order to use i2c protocol with the raspberry pi I use wiringPi library (http://wiringpi.com/reference/i2c-library/). In my code I have tested everything I've been able to, from all functionalities of the pmod: I get the temperature readings, set the frequency sweep params, make a freq. sweep measurement, etc. I have attached my code to this post (pmodIA_test.tar). All functionalities I tested seem to be okay, and everything seems to be working: I get the temperature, I can do a frequency sweep and if I connect the outputs of the pmod to an oscilloscope I can see the frequency sweeping (look at this video I recorded) Now, the thing is that even though everything seems to be WORKING, the result values I am getting back just make no sense AT ALL!!! For calibration purposes I am using a 100k resistor. In my code I first set the gain (X1) and range (2Vpp), I configure the sweep params and start it, then I calculate the gainfactor using that 100k resistor (which I later use on all my calculations), and then I ask the user to change the impedance and put the one that they desire to measure. On the main loop I simply do the frequency sweep, increasing the frequency at each step, calculate the impedance and put this value into an array (Z). I am also using gnuplot to display the results (the values obtained from the pmod are the exact same values that are being plotted using gnuplot, so this is not a display problem, as I checked this). This is when things get weird. These are the results I got for the following tests: 1) If I leave the 100k resistor for obtaining the impedance magnitude vs frequency I get the following curve ("100kresistor.png"). Just a noisy set of values, all of which are OVER 2 MEGAOHM. How is that possible, if I am using the same resistor I used to calibrate the pmod, that these results, for that same component, are so unaccurate? 2) (After the calibration with the 100k resistor)... If I place a 10uF capacitor in the connectors, I get the following curve ("Capacitor.png"). Now, the impedance of a capacitor should decrease with frequency according to 1/(2*pi*f*C). The curve I obtained, however, says otherwise. On the other side, the initial value of the impedance (2e+06) is almost the same as in the 100k resistor case, which is very suspicious. And here things get even weirder (at least to me). To connect the pmodIA with my protoboard I am using two SMA pigtails which carry the signals. 3) If I leave the circuit opened (using the pigtails) I get the following curve ("opencircuit.png"). This curve displays a peak at a certain frequency and then a decay (and at the end, it grows again). With an opencircuit I would expect to see, however, and +INF impedance, or a very high value (impedance of the air between the connectors). 4) If I take off the pigtails and repeat the same experience (open circuit) I get the following curve (opencircuit_NO_PIGTAILS.png). The results is almost identical, except that the values are lower. 5) If using the pigtails, I make a shortcircuit between the connectors, I get the following curve (shortcirtuit.png). This curve makes sense (at least a little bit, to me) as it is telling me that the pigtails are acting as inductors (because they are wires) and so that their impedance grows with frequency according to 2*pi*L. 6) If I take off the pigtails and shortcircuit the sma connectors in the pmodIA board directly I get the following curve (shortcircuit_NO_PIGTAILS.png). Again, like in the opencircuit case, the curve is almost identical to the one using pigtails, except that the values are a little bit lower. Some extra information: I am supplying 3V3 to the pmodIA through the raspberry pi. I am NOT connecting the SEL pin to anything (not GND nor VCC). How is it possible that I am getting these results? Is there something wrong with my code? Is my board broken?? Is maybe my settling time for the sweep configuration not right? Do I have to connect the SEL pin to GND or VCC? I would really appreciate your help as I need to finish this experiment in, at least, 1 month. Thank you so much for your attention, and let me know if you need more info. Manu B. Valentin
  9. Hello, My question is about the output current of the AD2, AWG. I know the current Max. Output is 10mA, but, I can't find if that current is expressed in Irms or it is Ipeak. I need to know that, because I want to build a box with a potentiometer inside, in order to control the output amplitude in an analogic fashion, setting the AWG out (sinewave) to 10Vpp (5Vp or 3.53Vrms) and set the potentiometer to taste to achieve the voltage needed. Trying to figure out what potentiometer I should use, doing the math tells me that a 50ohm pot is way too low to load the AWG output, taking the 50ohm output impedance from the BNC board and adding the 50ohm potentiometer, it gives 50ohm + 50ohm = 100ohm then 5Vp/100ohm = 50mA ... five times the Max Rated current of the AWG output if the 10mA is expressed in peak current, or 50mA x 0.707 = 35.35mA thre and a half times if it is expressed in rms current. So, doing the inverse math, with a maximum current of 10mA, and the maximum voltage coming out of the AWG, it gives : 5Vp / 10mA = 500ohm potentiometer or 3.53Vrms / 10mA = 353ohm (not a standard value). Could I use a 500ohm potentiometer safely to control the amplitude of the AWG output with no drop of the 5Vp? If I'm at the maximum output voltage and current, will it present more THD at this output? Thanks in advance Albert
  10. Hi all, I am Viviane working in impedance spectroscopy as my PhD research performing it in ionic solutions and cell solutions. I have a solution which is simply CaCl2 salt dissolved in water in the concentration of 0.4M and I am measuring the impedance spectrum of the setup using the equipment Gamry Interface 1000 in the frequency range 0.1 to 1MHz. I have done some measurements and got my results. My student worked in the measurements for one month and have done the same experiments as I did. When I compare the impedance measured in our results, in high frequency they are very similar (as I would expect, because we are measuring the same solution) but in low frequency they diverge significantly. Does anyone have any idea why would that be happening? Could it be some interference from a nearby equipment (some strong electric field from a nearby equipment)? Regards Viviane Teixeira
  11. Greetings, I need to know what is the output characteristic impedance of the VHDC connectors on the Genesys Virtex 5 FPGA Develpment Board. The datasheet only says they are impedance-controlled matched pairs and the schematic does not have this info. Some online forums said SCSI is defined by ANSI X3.13, the nominal diff cable impedance is 122 Ohms and I want to check if my board IO is consistent with this standard or not. I need to design a mating board to convert high speed differential signals into single ended, and signal integrity is a big deal. Thanks in advance, Emanuel
  12. I'm an electrochemist wondering if I can use the Analog Discovery to do impedance spectroscopy. I've ordered one to try out, but it hasn't arrived yet so I'm playing around with WaveForms 2015 software. I am no electrical engineer, so I have lots of questions. The normal settings we use in electrochemical impedance spectroscopy (eis) are as follows: Frequency range: 0.01-10,000Hz (1-10,000 probably ok), single sine wave to probe system: amplitude 10mV, use Nyquist (real/imag impedance) and Bode (freq vs impedance/ohm) plots to analyze the system. There are other settings such as wait time between frequencies, but I've found most of these in the WaveForms software. This type of test is usually used in corrosion analysis on coated and uncoated metals. Expensive programs use circuit modeling to extract system parameters, but you can also do analysis just looking at high or low frequency impedance. My question: is there a way to get WaveForms software to display Bode plots with impedance in ohms directly? Or at all?
  13. Please, I need informations about how to physically connect PModIA to the circuit for impedance measurement. Can someone send-me a schematics? Thanks.