attila

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attila last won the day on November 30 2018

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  1. Hi @StuE Here you can see the device configuration capabilities: >python Device_Enumeration.py DWF Version: b'3.10.2' Number of Devices: 1 ------------------------------ Device 0 : Name:'b'Analog Discovery 2'' b'SN:210321A419AA' Configurations: 0. AnalogIn: 2 x 8192 AnalogOut: 2 x 4096 DigitalIn: 16 x 4096 DigitalOut: 16 x 1024 1. AnalogIn: 2 x 16384 AnalogOut: 2 x 1024 DigitalIn: 16 x 1024 DigitalOut: 0 x 0 2. AnalogIn: 2 x 2048 AnalogOut: 2 x 16384 DigitalIn: 0 x 0 DigitalOut: 0 x 0 3. AnalogIn: 2 x 512 AnalogOut: 2 x 256 DigitalIn: 16 x 16384 DigitalOut: 16 x 16384 4. AnalogIn: 2 x 8192 AnalogOut: 2 x 4096 DigitalIn: 16 x 4096 DigitalOut: 16 x 1024 5. AnalogIn: 2 x 8192 AnalogOut: 4 x 4096 DigitalIn: 16 x 2048 DigitalOut: 8 x 256
  2. attila

    Maximum continuous sample rate

    Hi @StuE In record mode the device buffer is used as a fifo. The scan shift mode returns all the data fetched from the device buffer. It is not mend for recording, does not provide buffer overflow information. Record loop: FDwfAnalogInStatus(HDWF hdwf, BOOL fReadData, DwfState *psts); // fetch status and data FDwfAnalogInStatusRecord(HDWF hdwf, int *pcdDataAvailable, int *pcdDataLost, int *pcdDataCorrupt) cdDataAvailable - how many new samples are available since the last fetch cdDataLost/Corrupt - indicates fifo overflow, try to improve the loop performance, reduce sample rate, for AD select second device configuration to have more buffer Get the new data samples: FDwfAnalogInStatusData(HDWF hdwf, int idxChannel, double *rgdVoltData, int cdData); cdData <= cdDataAvailable
  3. Hi @fonak I thank you for the ideas. I plan to add CV/CC mode which will require auto resistor switching on wider frequency range, mentioned by @kojak
  4. Hi Mr. Attila,

    Thank you for helping me before.

    I would like to request another. 

    I want to read the Analog Input data of Channel 1 and Channel 2. I have tried several codes but there are lot of errors. Is there a simple code to get the data in an ai port?

     Kazumi

  5. attila

    DD triggered aquisitions to buffer

    Hi @Joker0208 You have simple trigger (combination edge, level) which you can configure in the T column, pulse (glitch, length, counter...) and protocol specific triggers. You can adjust the trigger position, number of samples and rate or time base according your needs.
  6. attila

    Buffer DD Pattern Generator

    Hi @Joker0208 Not yet, but thank you for reminding this.
  7. Hi @Ferdinand It looks like the first recorded sample is not valid. Until this software issue is fixed please skip the first sample. This code skips the first sample: AnalogIn_Record.py Thank you for the observation.
  8. attila

    Multi Device triggering

    Hi @dean8020 See following post:
  9. attila

    Help with pattern generator

    Hi @AlexRiga The custom pattern can be edited in the interface, with mouse on the signal, prefill generated (pulse, random or counter fur bus), edited in the table on the right side, signal imported from csv, txt files. Here 1MHz sample rate, with prefill of pulse 1 low and 999 high will generate 1us low, 1kHz signal
  10. attila

    Multi Device triggering

    Hi @dean8020 This looks like a wrong information... The Digital Discovery does not have dedicated trigger lines but any DIO or DIN line can be used for triggering, edge, pulse length or protocol specific trigger.
  11. attila

    Help with pattern generator

    Hi @AlexRiga Settings/ Device Manager/ 4th config Perform a capture with Logic Analyzer Export data Open Patterns, add signals, edit Import Select file, check column for signal adjust frequency as it was in Logic Analyzer. You may want to limit the imported signal to be periodic, like to 10k samples Do the same for the other signal. Select Auto Run and Repeat 1, or leave it with continuous if you need this way.
  12. attila

    WaveForms FM Modulation Index

    Hi @Rick314 The FFT/DFT tries to identify the sine wave frequencies that make up the captured signal. Having 1kHz FM on a 100ms capture period it means you have 100 cycles of modulation. After each cycle the carrier starts with a different phase, so the FFT can't correctly match sine wave on the capture. If you look at the frequency measurement which is performed progressively you see ~9kHz/~11kHz, but the FFT shows wrongly much wider spectrum. Here the FM frequency is 10Hz which is identical to the capture period of 100ms. With this the FFT can match more correctly sine waves to the capture and the 9/11kHz boundaries are is identified correctly. Before the FFT process a Window is applied on the capture to reduce the calculations errors due to non full period components, by smoothing the ends of the captures. Here to illustrate the process, I added as M1 a "FlatTop" window and M2 applied on the data. Because of the window the spectrum is not symmetrical, only about half of the capture reaches the FFT. http://download.ni.com/evaluation/pxi/Understanding FFTs and Windowing.pdf Setting the FM to 20Hz (50ms) we will have about one period of modulation in the windowed domain.
  13. attila

    Help with pattern generator

    Hi @AlexRiga You can use clock with 99.99% duty or configure pulse signal or custom pattern. To have more buffer for custom on Analog Discovery under Settings/ Device Manager select the 4th configuration.
  14. Hi @m@tt The calibration frequency depends on your requirements. You can do it monthly, yearly, biannually or never, or before any critical project... For school or hobby use where high accuracy is not important, you can leave with the factory calibration. A important source of error is the temperature drift, which causes mostly offset error, of about 40ppm/*C. To prevent/minimize such, leave the device for 10-30 minutes to heat up before starting the measurements. This is also important before calibration. During the factory calibration the boards are at about 40-45*C You can also use the "Zero offset" before each Scope measurement. This will do a quick calibration based on acquisition, canceling the offset error of the device, cabling or measured circuit.
  15. attila

    Waveforms v 3.7.5 crashing on OS X 10.9

    Hi @Baker Steve Thank you for the feedback. In case a device is not recognized, as a general troubleshooting method for any device: 1. disconnect the device, restart its application, connect the device 2. disconnect the device, reboot, connect the device, start its application