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test-and-measurement:analog-discovery-pro-3x50:logging-data-to-usb [2022/09/12 14:57] – changed forum.digilentinc.com to forum.digilent.com jeff.greenberg_ni.comtest-and-measurement:analog-discovery-pro-3x50:logging-data-to-usb [2022/10/04 11:38] (current) – external edit 127.0.0.1
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 +====== Logging Data to a Flash Drive with Analog Discovery Pro (ADP3450/ADP3250) ======
 +~~TechArticle~~
  
 +<WRAP center round todo 60%>
 +This page is under construction.
 +</WRAP>
 +
 +===== Overview =====
 +<WRAP group>
 +This guide demonstrates using the Analog Discovery Pro in Linux mode to automate data logging directly to a USB flash drive. Automation is accomplished using WaveForms SDK and Python 3. Before following this guide, make sure that you run the latest Linux version on your device. Follow this guide to update the Linux on your Analog Discovery Pro: [[test-and-measurement:analog-discovery-pro-3x50:recover-linux-mode|]].
 +</WRAP>
 +----
 +
 +===== Inventory =====
 +<WRAP group>
 +  * [[test-and-measurement:analog-discovery-pro-3x50:start|Analog Discovery Pro (ADP3450/ADP3250)]]
 +  * A FAT/FAT32 USB drive
 +  * [[https://ttssh2.osdn.jp/index.html.en|Tera Term]], [[https://www.chiark.greenend.org.uk/~sgtatham/putty/|PuTTY]], or any other terminal emulator of your choice
 +</WRAP>
 +----
 +
 +===== Boot Into Linux Mode =====
 +<WRAP group>
 +<WRAP group><WRAP column half>
 +Mode selection can be done through WaveForms using the Device Manager. With the Analog Discovery Pro connected to the host computer by Ethernet, open WaveForms. If the Device Manager hasn't opened yet, then click Settings -> Device Manager.
 +</WRAP><WRAP column half>
 +{{ :test-and-measurement:analog-discovery-pro-3x50:usb_st.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Select the Analog Discovery Pro from the device menu, then click the Boot button. The Boot Mode window should open. By default, Standard Mode which allows the user to communicate with the instrumentation device over USB or Ethernet will be selected.
 +
 +To change to Linux Mode, select Linux, then click "Apply & Reboot".
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:linux_mode.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +At this time, an audible click should be heard and the Analog Discovery Pro will disconnect from WaveForms. About 10-15 seconds should pass before it reconnects. Confirm that the second column next to the Analog Discovery Pro says "USB Linux", confirming the mode has successfully been switched.
 +</WRAP><WRAP column half>
 +{{ :test-and-measurement:analog-discovery-pro-3x50:usb_lx.png?400 |}}
 +</WRAP></WRAP>
 +</WRAP>
 +----
 +
 +===== Connect Through a Terminal Emulator =====
 +<WRAP group>
 +<WRAP group><WRAP column half>
 +Find what serial port the Analog Discovery Pro is connected to and note it.
 +
 +Open a terminal emulator such as PuTTY or TeraTerm and connect to the noted serial port using 115200 Baud, 8 data, 1 stop, and no parity bits.
 +</WRAP><WRAP column half>
 +{{ reference:test-and-measurement:analog-discovery-pro-3x50:terminal-settings.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Login with username: "digilent" and password: "digilent".
 +</WRAP><WRAP column half>
 +{{ reference:test-and-measurement:analog-discovery-pro-3x50:linux-mode-login.png?400 |}}
 +</WRAP></WRAP>
 +</WRAP>
 +----
 +
 +===== Mount the Flash Drive =====
 +<WRAP group>
 +<WRAP group><WRAP column half>
 +Download {{ :test-and-measurement:analog-discovery-pro-3x50:logger.zip |this}} package and extract the contents onto the USB drive.
 +
 +Plug the USB into the back of the Analog Discovery Pro. In the terminal, type <code>sudo fdisk -l</code> to find the USB device path. It should look like ///dev/sd<drive letter><partition number>//. This guide will use /dev/sda1 in its text and images, and care must be taken to match the drive letter and partition number of your USB drive.
 +</WRAP><WRAP column half>
 +{{ reference:test-and-measurement:analog-discovery-pro-3x50:fdisk-output.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Make the drive contents accessible by entering the command <code>sudo mount /dev/sda1 /mnt</code> and then <code>cd /mnt</code> to navigate into the USB's directory.
 +</WRAP><WRAP column half>
 +{{ reference:test-and-measurement:analog-discovery-pro-3x50:mount-usb.png?400 |}}
 +</WRAP></WRAP>
 +</WRAP>
 +----
 +
 +===== Script Overview =====
 +<WRAP group>
 +<WRAP group><WRAP half column>
 +Import the necessary Python packages, then define the name of the output file and the drive letter and number of the USB drive.
 +</WRAP><WRAP half column>
 +<code python># import modules
 +from ctypes import *
 +from dwfconstants import *
 +from subprocess import call
 +import sys
 +
 +# parameters
 +filename = "voltages.txt"
 +drive = "sda1"</code>
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +Load the WaveForms SDK dynamic library, then open the device.
 +</WRAP><WRAP half column>
 +<code python># load WaveForms SDK
 +if sys.platform.startswith("win"):
 +    dwf = cdll.dwf  # on windows
 +elif sys.platform.startswith("darwin"):
 +    dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf")
 +else:
 +    dwf = cdll.LoadLibrary("libdwf.so")
 +
 +# global variables
 +hdwf = c_int()  # device handle
 +
 +# open device
 +dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))  # open first device
 +# check for errors
 +if hdwf.value == hdwfNone.value:
 +    print("failed to open device")  # display error
 +    quit()</code>
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +Initialize the Oscilloscope. If you want to use a different instrument, change this part at your will.
 +
 +Mount the USB storage. If the file system is already mounted, this command will only return a message. Set the path and the name of your file.
 +</WRAP><WRAP half column>
 +<code python>try:
 +    # initialize the oscilloscope
 +    # enable the channel
 +    dwf.FDwfAnalogInChannelEnableSet(hdwf, c_int(0), c_bool(True))
 +    # set 0V offset
 +    dwf.FDwfAnalogInChannelOffsetSet(hdwf, c_int(0), c_double(0))
 +    # set the range from -5V to +5V
 +    dwf.FDwfAnalogInChannelRangeSet(hdwf, c_int(0), c_double(5))
 +    # start the oscilloscope
 +    dwf.FDwfAnalogInConfigure(hdwf, c_bool(False), c_bool(False))
 +
 +    # mount the USB strorage
 +    call(["sudo", "mount", "/dev/" + drive, "/mnt"])
 +
 +    # set file path
 +    filename = "/mnt/" + filename</code>
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +Load and save the oscilloscope data in a buffer, then write out the content of the buffer to the file. The file remains opened, until the script runs.
 +</WRAP><WRAP half column>
 +<code python>    # create/open the file
 +    with open(filename, "w") as f:
 +        while True:
 +            # measure voltage
 +            # load internal buffer
 +            dwf.FDwfAnalogInStatus(hdwf, False, None)
 +            voltage = c_double()    # buffer for raw values
 +            # save the internal buffer
 +            dwf.FDwfAnalogInStatusSample(hdwf, c_int(0), byref(voltage))
 +            voltage = float(voltage.value)   # get voltage values
 +
 +            # save voltage
 +            f.write("{}\n".format(voltage))</code>
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +Finally, exit the script on "Ctrl+C", then reset the used instruments and disconnect from the device.
 +</WRAP><WRAP half column>
 +<code python>except KeyboardInterrupt:
 +    # exit on Ctrl+C
 +    pass
 +finally:
 +    # reset and close the device
 +    dwf.FDwfAnalogInReset(hdwf)  # reset the oscilloscope
 +    dwf.FDwfDeviceClose(hdwf)   # disconnect the device</code>
 +</WRAP></WRAP>
 +</WRAP>
 +----
 +
 +===== Testing =====
 +<WRAP group>
 +Start the script with the following command:
 +<code>sudo python3 /mnt/logger.py</code>
 +To terminate the script and to close the file, press "Ctrl+C" on the keyboard. When the script is exited, the file is saved on your USB flash drive.
 +</WRAP>
 +----
 +
 +===== Next Steps =====
 +<WRAP group>
 +The script can be modified as needed for your project.
 +
 +For more information on WaveForms SDK, see its [[software:waveforms:waveforms-sdk:start|Resource Center]].
 +
 +For technical support, please visit the [[https://forum.digilentinc.com/forum/8-test-and-measurement/|Test and Measurement]] section of the Digilent Forums.
 +</WRAP>