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Jeffrey

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Posts posted by Jeffrey

    Reading data files with *.wdd format from WebDAQ-504

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hello @Sajad

    Measurement Computing provides you with 2 options to convert WebDAQ data files (.wdd) to csv:

    Conversely, 

    the link you provided (

    21 hours ago, Sajad said:

    https://kb.mccdaq.com/KnowledgebaseArticle50726.aspx

    )

    offers you the option to create your own app.  Perhaps you didn’t quite understand the knowledgebase article?  The file is divided into three sections and only one of them is json format.  There is a fixed size binary header (not json), followed by a json header (the size of the json header can vary and is defined in the last 4 bytes of the binary header), followed by binary data until the end of the file.

    Note that the Newtonsoft.Json nor built-in json package of Python, when used by itself will not work as it does not handle the other 2 sections of the .wdd file.

    There is also a REST api that allows you to access the data as it is collected by the WebDAQ.  More information on this is located  https://www.mccdaq.com/downloads/WebDAQ/REST-API/1.0.0/

    Thanks,

    Jeffrey

    Library Installation for MCC DAQ HAT for Raspberry Pi 4

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hello @Duc Anh Nguyen

    Click on the Raspberry Pi 4's Start icon, and then Preferences >> Raspberry Pi Configuration.

    Click on the "Interfaces" tab, and enable SPI and I2C.

    Reboot the system and try accessing your DAQHat from the MCC DAQ HAT Manager control panel.

    If that still fails, then I will need to know:

    What model(s) daqhat you have?

    What version Raspberry Pi are you using?

    What OS version are you using?  You can run “cat /etc/os-release” if you cannot remember.

    Are you running the graphical version of the OS or terminal only?

    Are any other applications running when they have the problem?

    Do you have any other HATs attached to the RPi?

    Thanks,

    Jeff

    DASYLab display lag - live display falls progressively more behind real time

    in Data Acquisition (DAQ) & Data Logging

    Posted

    This is a known phenomenon of DASYLab when used with software paced acquisitions as you are using in your worksheet.

    This occurs because the timing values used in some of the drivers does not pass the same number of significant digits of a floating point number to the calling software, so after a while there is a time lag.

    "How to fix this?"

    Change the timebase of the USB-1408FS from DASYLab to USB-1408FS -Input HW, and modify the scan rate to 60 Hz.  This will set the block size to 6.  You can either decimate the data using the separate module:

    image.png

    or, average the data in the bock using the Average module:

    image.png

    Keep in mind that DASYLab abhors when data from more than one source,  does not arrive at the inputs of module at the same time.  The fix for this is to write these individual values to Global Variables, and read them into the receiving module such as the Write Data module.  I cannot test your worksheet as I do not have your serial port device, but I have edited your worksheet to include these changes.

    457527162_RIGTest1LCver1_rev1.DSB

    ADP5250 Logging/Recording

    in Test and Measurement

    Posted

    Most data acquisition devices don't read 0V when nothing is attached.

    Their inputs are high impedance so they only require a tiny amount of current.  Because of this trait, they act like antennae.  So with nothing attached, you cannot trust what you see.  you need to have a known input source or signal attached else.

    Using  the capacitance/static electricity on your fingers is a good test to see if the device is responding but that is all that test is worth.  Keep in mind that an abundance of static could damage the instrument due to the static discharge, so it is not recommended.

    Creating an LabVIEW installer with LV_Link Library

    in Data Acquisition (DAQ) & Data Logging

    Posted

    According to my system, the help file is located C:\Program Files (x86)\National Instruments\LabVIEW xxxx\help\DT-LV_Link3.chm

    where 'xxxx' is the version of LabVIEW.

    This is the contents of that help topic (there are no links on that page)...

    Building and Distributing an Executable

    If you want to create a stand-alone executable of a VI that you have created, you need LabVIEW's Application Builder. The Application Builder is included as part of the LabVIEW Professional Development System and is also available as a separate option that you can purchase from National Instruments.

    The Application Builder creates executables from user-specified files (such as VIs, libraries, documentation, data files, and so on) and saves individual build settings as part of the project file.


    Note: If you are running a version of LabVIEW that is newer than 8.5.1 (32-bit) or 2009 (64-bit), you may get a warning message about "unsaved changes." In most cases, you will want to save the VI to run in the version of LabVIEW that you are using. However, once saved, the VI cannot be read in older versions of LabVIEW. If you decide to save the VIs, it is recommended that you do a mass compile, removing the read-only attribute of the VIs. Refer to your LabVIEW documentation for details.


    To create an executable, perform the following steps:

    Open the VI that you want to build into an executable.

    From the Tools menu, click Build Application (Exe) from VI....
    The default project name is displayed. If desired, you can change the default project name.

    Click Continue.

    Specify the application information, including the name of the build specification, the name of the executable you want to create, the destination directory of your executable, version information, and a description of your executable.
     

    Note: If desired, you can customize settings, preview the file organization, and specify the languages that the application will support by clicking OK, and modifying the Build Specifications Properties dialog. See the documentation for the Application Builder for more information.

    In LabVIEW 2009 and greater, ensure that you change the destination folder so that the executable is not located in the user.lib folder of LabVIEW; otherwise, errors will occur.

    Click Build.
    The Application Builder creates an executable of your project based on the specified build specifications.

    After successfully building an executable, run your executable to verify that it works as designed. If desired, you can also create an installer for the executable using the Application Builder. See the documentation for the Application Builder for more information.

    ADP5250 Logging/Recording

    in Test and Measurement

    Posted

    Hello @tfkrauss

    the WAVEFORMS logger defaults to 1 sample per second, and max's out at 10 S/s (100 mS/sample)

    I'm unclear what you mean by "recording at high resolution".  Assuming you mean at a high sample rate?  What rate?

    There is an example in the WaveFormsSDK titled AnalogIn_Acquisition.py, it demonstrates sampling at 20 MHz with a buffer size of 4000 samples.

    I have a VB.NET version of this example if you prefer.

    In either case, you would need to flesh out this example by adding the ability to save the collected data to file.

    There are plenty of resources on line demonstrating writing data to file.

    Append a datafile of manually triggered readings instead of rewriting it?

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hello @AndrewV

    Unfortunately no.  DAQami will create a new file with each new trigger.

    if you mean you want one sample at each trigger, such as a button press for example, then I recommend you connect your trigger source instead to the external clock in (AICKI). (1 trigger : 1 sample)

    However if you mean you want to collect a number of samples for each trigger, then the digital trigger input is correct. (1 trigger : many (>1) samples)

    DAQami does not include a feature for external clock.  so in either scenario you will need to use a different software.  Choices are:

    DASYLab (Basic or higher)

    LabVIEW

    Write your own app in a Universal Library supported language such as VB.NET, C#.NET, C/C++, or Python.

     

    Lost connection to USB-1608G and USB-TC; requires unplugging and plugging USB

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hello @MattA

    Measurement Computing USB devices such as the USB-1608G and USB-TC, when directly connected to a computer automatically power up along with the computer. 

    Reasons they would not power on with the computer are:

    • Bad USB port.
    • Using USB cables longer than the published spec found in the User's manual (3 meters / 9.84 feet max).
    • Using a USB cable extender.
    • Using an external USB port expansion device (unpowered or powered).
    • Under powered USB port.
    • Wrong or incorrect power management settings for the USB Root Hub found in the device manager (don't let the port power off). 
    • Bad of faulty installation of Windows OS (run Windows update, or anti virus software).

    These are the ones we are aware of.

    Using LabView to control the USB2020 to acquire data at 20MS/s/ch

    in Data Acquisition (DAQ) & Data Logging

    Posted

    Hello Ke,

    The USB-2020 is fully capable of acquire data at 20 MHz in LabVIEW using ULx for NI LabVIEW.  You need to nothing special to enable BURSTIO other than in the ULx Timing.vi set the samples per channel above 8 MHz, and set the sample mode to 'FiniteSamples'. 

    Note that the USB-2020 cannot run in continuous mode when BURSTIO mode is enabled.

     

    The ULx example: ULx Acq&Graph Voltage-Int Clk.vi is the correct example to use here.

    Measurement Computing's Support Engineers can help you with getting the USB-2020 to operate and acquire data in a supported software such as LabVIEW, however what you do with the data once it is acquired is up to you to implement. To write the data to file, I recommend you look at the Express VI, Write To Measurement File.vi

    USB-1616FS systematically stops working

    in Data Acquisition (DAQ) & Data Logging

    Posted

    14 hours ago, Antovigo said:

    * The voltages readers, when used on their own, can work for an extended period of time without problems

    * It's when I run it while doing operations using the ERB24 switchboards from the same computer that it crashes

    Is the app that runs the USB-ERB24, the same app that controls the USB-1616FS?

     

    14 hours ago, Antovigo said:

    When the ERB boards are running, I often hear the sound effect that signals that there was a problem with one of the USB devices (I'm not sure what this means exactly, since it's just a sound). I think this often happens when turning a switch off.

    The only USB related computer sounds I am aware of are:

    • 2 tones played low tone then high tone means a a device was attached and drivers are loaded.
    • 2 tones played high tone then low tone means a device was removed and/or drivers unloaded.
    • is either of these what you are hearing?

    How are you connecting your '1616FS and ERB24(s?) to the computer? 

    • Are you using the USB cables that came with these devices (ie 2 Meter cables)?  or are they ones you are using longer?
    • Are you using a USB HUB? (if yes, powered or unpowered?)
    • Are you using a USB cable extender?
    On 9/8/2022 at 10:52 PM, Antovigo said:

    The LED starts blinking regularly and there is no measurement anymore.

    This means the micro on the device has lost connection and is no longer communicating with the computer, or the micro is 'confused' (in a state where it doesn't know what to do).

    Since this occurs when a relay energizes or de-energizes,

    is there a particular relay every time?  this could mean there is an electrical arc or spark feeding back up the USB cable.  The relays used on USB-ERB24 are equipped with flyback diodes across the coils to snub any fed-back signal, but if your signal is large enough the spark or noise could jump the diode and cause the system to hang.  As a test, you can test this by disconnecting the signals to the relays.

    Lastly, just some basic questions:

    What is the computer's operating system?

    What version of InstaCal do you have installed?

    What is your app written in?

    Have you tried your setup on another computer?

    I have never heard of someone having to repeatedly install/uninstall the MCCDAQ software due to this reason.

    14 hours ago, Antovigo said:

    Do you know if there's a way to tell exactly what's going on when the USB-problem sound effect is played? Is there a way to diagnose the units and their connection to the computer? Is there any log from the 1616FS that could give me information about the crash?

    Q1:  see above.

    Q2:  not that I am aware of.

    Q3:  https://www.partitionwizard.com/partitionmagic/windows-10-crash-log.html

     

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