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What data would you acquire with this?

OwainM

We're appraising the NI USB-6421 for a RoadTest and would appreciate some member input.
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It's USB Type-C powered and has analogue and digital IO and 4 counters, analogue input channels with four input range settings between ± 200 mV to ± 10 V. The analogue output channels have an update rate of 250 kS/s/ch at up to ± 10 V.

It's compatible with some free data acquisition software from NI, but also has some professional software to use with it that's also available.

The full product specifications are available below:



Thanks for reading and commenting below

  • I didn't vote - none of the suggestions fit.

    This kind of box might be useful for multichannel applications but has several limitations that some people seem to have missed.

    There is no specification for round trip latency - ie the time taken to measure an input and adjust an output  - because of buffering and the USB interface it will be slow and jittery - so applications like DAB's acoustic levitation experiment won't work.

    It's slow (as   has pointed out) - very slow, the 250kHz sampling rate is only true if you just use 1 channel, for 16 channels its 15.6kHz.

    There is no input filtering - and the input bandwidth is approx 500kHz  - so you will have noise problems.

    So the extra bits had better include some way of doing filtering.

    Looking back over many years of measuring stuff I can see it being useful in component testing where you might want to test several parts at once and over a long time and will need to build a decent test jig anyway. When I've done this I've mostly used a DMM or a DMM with multiplexing built in or a scope for faster stuff. 

    MK

  • I would like to use this in a project that i am currently working on to study the power and the performance of the motor and also the current consumption as well. This would be a handy tool to capture all the data that would be necessary for the studies. 

  • Well, ADCs with 250 kB/s are relatively slow.

    So, they're mainly suitable for measurements involving slow movements.

    For example, an athlete running on a treadmill can be used to measure their vital signs.

    Or in the field of chemistry, color gradients of chemical substances (I worked in the 1980s for a company that manufactured multi-input blood analyzers and chromatographs), or physical relationships in gears, the fracturing of materials, etc.

    The analog outputs can be used, for example, for the fine-tuning of valve flaps.

    Please read the spec.:
    https://www.ni.com/docs/de-DE/bundle/usb-6421-specs/page/specs.html

    The digital inputs/outputs can also control the associated devices, such as relays, valves, or other switching operations, to automate the measurements.

    In the smart home sector, automated devices can now be easily controlled using the Raspberry Pi. This is what I see for my projects.

    So, this was the hardware.

    Software - here you have an extra cost, for the FlexLogger professional:

    FlexLogger Professional (785748-3501)
    FlexLogger Professional, Abonnementlizenz (Subscription license), Download
    € 575,00
    Recommended for automated, extensible data logging with NI DAQ hardware. Automate tests with alarms, triggers, and events, and extend functionality with plug-ins.
    Key Features
    Multi-Chassis Synchronization: Synchronize multiple NI chassis for accurate, time-aligned measurements with a high channel count.
    Logging Triggers: Automatically start, stop, or segment data recording based on sensor thresholds or other conditions to capture only what matters.
    Events: Respond to specific occurrences during a test, such as activating devices when a condition is met (for example, starting cooling fans when the temperature exceeds a threshold).
    Automation APIs: Control and monitor FlexLogger from external applications (Python, NI LabVIEW, or NI TestStand), enabling integration into larger automated test systems.
    Computational Channels: Perform real-time mathematical operations on captured data (averages, RMS, custom formulas) to track derived measurements during test execution.
    Plugins: Extend FlexLogger with custom LabVIEW or Python plugins to integrate third-party hardware, perform custom analyses, or connect to lab systems.
    CAN/LIN Data Recording: Capture and record vehicle network data along with sensor measurements for complete vehicle or subsystem testing.
    ---
    FlexLogger Lite (790818-35)
    FlexLogger Lite, Abonnementlizenz, Herunterladen
    kostenlos (free)
    Recommended for fast, interactive data acquisition with NI-DAQ hardware. Quickly configure, view, and record sensor data—ideal for simple tests, no programming required.
    Key Workflows
    Configure Measurements—Quickly set up channels from NI-DAQ hardware, scale, and label signals so you can start capturing meaningful data immediately.
    Create Dashboards—Build drag-and-drop dashboards with graphs, numeric displays, and other visuals to monitor live signals during a test.
    Save Results—Save log data in standard TDMS or CSV formats for easy review, sharing, and analysis in tools like Excel, NI DIAdem, or the TDMS Viewer included with FlexLogger.
    ---
    I would suggest the pro version.

  • 16Bit at  250 kS/s/ch?  I'd love to make it read high precision analog sensors, Especially GMR based rotation position sensor in the field of robot joint to verify a Toque-Velocity-Position Loop 

  • Very interesting device.

    I can see multiple projects for using the DAQ.

    1. Drive speakers to see if you can get acoustic levitation.

    2. Drive speakers to see mandalas patterns.

  • The only project I'm doing right now that could use this capability is a system with 8 piezo sensors that processes impact waveforms. The NI system could be used to capture raw waveforms that can be compared to the processed outputs.

  • I would use it to collect synchronized electrical, mechanical, and sensor data, including voltage, current, frequency, RPM, vibration, temperature, digital states, pulse timing, encoder position, startup behaviour, power consumption, and response to generated test signals. It would support automated testing of turntables, speakers, amplifiers, controllers, grounding systems, and other electronics, with the data logged for graphs, comparisons, fault detection, and pass/fail reports.