Jon Frey

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  1. Jon Frey

    AD2 Ehnacement Milliohmeter Version 2

    It will be a few weeks before I can look at this virtual instrament ,I am traveling and dont have labview available Attila would be best suited to answer I do recall some conversations stating you cant reprogram AD2 FPGA, but may not be necessary This thread keeps getting better,that would be an excellent function for many measuremnts
  2. Jon Frey

    AD2 Ehnacement Milliohmeter Version 2

    Wanted to stay within Digilent tools and use the logger application for triggering,control and display From than I can save,record over time or display using the logger application itself. However I don't see a one shot measurement, or a one sample selection in the application, so unless we can incorporate/accommodate the sampling function internal to the app, it may not be usable.The record time and update rate are fine , we can adjust update rate for the run time of the special script, but the minimum samples is 10. I suppose that might still be OK if the data is stable in memory after we run the script sequence, so that the extra sample sequence is harmless. Calling multiple waveform applications , while scripting in another is unclear to me. (Controlling AWG1,AWG2, Scope from logger script ) Also unclear is possibility of calling routines developed using the SDK from within a script. The only programming environments I have used are Octave and Python(<3.0)
  3. Jon Frey

    AD2 Ehnacement Milliohmeter Version 2

    Impedance analyser wont work as two outputs are needed I was hoping to use logger to run script/outside program and do any post process math It may even be possible to use Analog Parts kit hardware included in Digilent parts kit to do the whole job. Checking amps in the kit,since do not need to convert amp output Put component count as tiny to get microamp resolution
  4. Jon Frey

    AD2 Ehnacement Milliohmeter Version 1

    I neglected to attach the source document that this design was derived/adapted from. LowOhmsAdapter_3.pdf
  5. In researching simple circuits for low resistance measurements I cam across the attached design Low ohm Measurements.pdf It seems elegant and well suited to enhancing the AD2 and would be a simple add on board Several resistors and an op amp, as shown but may need a digital voltage level shifter if that AD2 output is to0 limited. However the software requirements are beyond my limits. Can it be done in scripting or would it need a new instrument in Waveforms ? I will share a build with anyone willing to help Might be something for Digilent to look at ?
  6. I have a need for small resistance measurement and would prefer to stay with AD2 . A simple circuit addition with just a few components, BNC adapters and Kelvin clips seems simple enough .Controlled current source at approximately 100 MA and 4 point measurement The LM317 can be replaced by alternate devices , designs are common . Calibration and display in ohm unit could be done in the logger function with measurement of the actual controlled output current . It would be nice if the voltmeter function had the capability to adjust the units displayed and capability to do the required basic math . Can anyone validate this approach as compatible with the AD2?
  7. Jon Frey

    AD2 Enhancement -Voltmeter

    I believe it would be useful to have the same data field description editing and basic math functions that are available in the logger implemented in the voltmeter function. Scripting wouldn't be needed Frequently a voltage is representative of some other physical quantity being measured and there is a simple scale factor that needs to be applied mathematically. All that may be needed at some times is just a single manual measurement . Particularly during setup and calibration. A single value displayed in the engineering unit being investigated is what is desired . I don't see in the logger the ability to do that, minimum samples is 10 , minimum update i 1 s and data must be read off graph ( even in single mode )
  8. 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
  9. Jon Frey

    Impedance instrument AD2

    Thanks for the swift reply and referral to Attila Adding one more observation and a question 5) Compensation carry over from analyzer to meter seems to have a glitch I did a open and short compensation in an analyzer sweep. When I switch to meter mode at the fixed frequencies , including the end points of the sweep , I get warning message stating no short compensation. No setting changed , only running single shot record It only complains about the short comp and is happy with the open comp recorded in the other screen. 5a) Are they separate tables for meter and analyzer? 5b) Will the sweep always get these fixed points or will it miss them due to range selected divided by samples selected in the sweep. 6) Nit picky observation, but spelling error in the warning message
  10. Jon Frey

    Impedance instrument AD2

    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 ?
  11. Jon Frey

    Analog Discovery troubleshooting

    Managed to capture startup sequence with the new AD2. Conversion is 1 mv to 1 ma Shows the failed start and retry after 125 MS . Did not see it reached cutoff currents to cause failure and the reported current in the error message did not match the reading on the scope Could not capture any time it reached the steady state , delay was too long Any time it reached flashing ready light status the current was around 246 ma I am confident in the current readings from my setup, current reported on the new AD2 status bar and the instrument setup are within 5% New AD2 , without any load pulls around 300 ma at 5.00 supply from USB cable I also see a voltage discrepancy of about 4 % between what the AD2 voltmeter reads and the status bar state Thanks for the help , I will pursue this as a latent hardware failure with sales. I was hoping it was not deceased . merely confused..
  12. Jon Frey

    Analog Discovery troubleshooting

    The new AD2 is functioning correctly. My parts to capture the startup current and voltages on the malfunction unit have been delayed by the northeast weather conditions. I will still want to do that , I am suspicions that the detected and displayed currents are in error Screen shots with explanation per request Screen shot on cold start, device plugged into USB, Waveforms launched ,( device data is being read, setup started I presume ) This is a "splash screen" that closes itself Next screen is PLL error message , cold start current can be 1058 to 263 ma Hot start runs 263 to 63 ma Closing this screen gives , device not found error However ,the status light is on and closing this window shows the AD2 listed able to be selected. The sequence repeats itself if trying to boot by selecting the device. The first splash screen may or may not repeat and the currents reported in the error message vary , but have the three common average values 1058, 265, 63 Aha! Doe we have a bit error 64, (128), 256, (512), 1024 The status light does not appear change when initiating hot starts Closing the "No device detected ", error presents the
  13. Jon Frey

    Analog Discovery troubleshooting

    I am trying to boot with a bare AD2.only. New questions 6) What does the LED flash represent ? I obtain LED flash state ,only after boot attempt, and it exhibits correct power supply status ( Double flash with aux attached , single with USB only. 7) When first starting Waveforms , the device is recognized and a window appears loading the serial number etc Next the PLL lock error appears , from apparent auto boot attempt. Closing the PLL error window ,a " no device found error message" appears that was hidden under the PLL window I assume this is simply a messaging problem and the no device found error should have been superseded by the loading data screen ? Going back to question 1 ) Is the error triggered by an internal current reading, or some other cue? Should I break out a USB cable to verify current provided ? I am interpreting your response as the PLL error is only triggered by current excess or voltage out of range. There is no subsequent error thrown for timing clock not started? Reviewing the manual on power up,monitoring actual startup events will require some effort due to the timers in the power monitoring. I have received my new AD2, so can use it to troubleshoot problem unit. I have ordered a powered ( 2.5 amp ) USB hub, USB cable breakout boards , a current to voltage analog converter board I will see if I can monitor and capture USB supply voltage and current on the malfunctioning unit and report back results Materials wont arrive for several days
  14. Jon Frey

    Analog Discovery troubleshooting

    As stated, I have tried 3 computers , different ports , two cables . Adding the AC adapter makes no difference Includes the equipment where the AD2 was previously working The highest power setup will repeatedly show 1058 ma , but AD2 will not boot. After repeated attempts in Waveforms, with no physical change to the setup , the current shown typically drops to 250ma It will then repeat that level on further attempts , with a infrequent drop to around 63 ma Voltage does not appear to be an issue , error message voltage is 5v =/- 1% In other posts of this issue I see similar numbers . One post shows AD2 functioning with operating current at 960 ma Questions 1) Is the error triggered by an internal current reading, or some other cue? Should I break out a USB cable to verify current provided ? 2) What is the required start and operating current ? Can not be more than 500 ma for USB2 standard ports 3) PLL Failure at 1058 ma should not occur? 4) The AC adapter is capable of 4000 ma , but the boot up sequence is unclear. Will the AD2 switch from USB to adapter prior to initiating the rest of the device ? 5) Is there any method via the SDK to query the verify the device is actually failed and it is not a software error reporting a false positive and then preventing Waveforms from launching? ( Since the Adept utilities are not applicable ) I have already ordered another AD2 I cannot afford the same issue with it, and do not even want to power it until I understand this problem, I am on hold with my project until resolved Future need will be 3 to 5 units , one or two for excitation, one or two for data and one for general use on circuitry Can I send in the problem unit for examination?
  15. Jon Frey

    Analog Discovery troubleshooting

    I am having similar PLL1 issues on startup with previously functioning AD2, and I see other threads with same issue including new out of box units It is not clear what the currents in the error message represent Actual draw or available current ? I have tried 3 computers , multiple ports and with and without the Digilent AC adapter Current stated in error message with PC supply only ,will vary from 1000 ma to 60 ma , with typical value at 250 +/-10 With AC adapter the USB current drops to minimal 4 ma and the adapter shows the 250 +/- 10 dadutil shows the device Product name Analog Discovery2 User Name Discovery2 Serial 210321A41853 Product ID 40300360 Firmware 010A Transport 00020001 USB Capability 00000000 dsumecfg readbootsec or read sec 1 fails with error message failed to initialize scan chain failed to configure FPGA djtcnfg init fails with error message failed to initiate JTAC ecc1 I haven't powered up the AD2 in several months , but have been assembling a custom breakout board and test assembling PC mount header connectors to the unit. I am concerned about the recent posts of this type error . I have invested design time around the AD2 and must be sure it is not a flaw before I buy a replacement and continue down the path I am on Have any returned units be analyzed for the origin of the fault?