SMU and VPS Devices

Refer to the following sections for information about setting up a SMU and VPS instruments in InstrumentStudio.

SMU/VPS Modes of Operation

Device Operating Modes

You can use one of the following modes for acquiring measurements using an SMU or VPS device in InstrumentStudio: Chart, Waveform, and Sweep.

Operating Mode Sourcing Behavior Large Panel Plotting Behavior Pause Behavior Potential Uses Notes
Chart Allows one or more channels to source current or voltage. Appends samples to the chart as they are measured. Channels continue to source at the last configured level when you pause measurements. Observe signals over an infinite duration.
Waveform Allows one or more channels to source current or voltage. Plots samples to the graph all at once; the length of the graph is determined by capture time. Channels continue to source at the last configured level when you pause measurements. Observe signals over a shorter, finite duration, similar to an oscilloscope. Unless you press Single, InstrumentStudio automatically configures the device for a faster sample rate and runs the output continuously in a loop.
Sweep Sweeps through configured current or voltage steps for a single channel (Single-Channel Sweep) or two channels (Two-Channel Sweep). Plots sample step results on the graph as they are measured. Both measurement and output channels are paused when you pause measurements. Allows you to plot the relationship between current and voltage in an I-V curve. When you are using Two-Channel Sweep, the sweep acts as a nested loop, where the inner channel executes all the steps for each step configured in the outer channel.
Sweep (LCR Mode) Sweeps through configured frequency or DC bias steps for a single channel (Single Channel Sweep) Plots sample step results on the graph as they are measured. Both measurement and output channels are paused when you pause measurements. Allows you to plot the relationship between frequency or DC bias and enabled LCR readbacks.
Note Waveform and Sweep modes are not available on PXI-4110, PXIe-4112, PXIe-4113, PXI-4130, or PXI-4132 devices.
Note Waveform mode is only available for single-channel sessions in debug mode. Waveform mode is disabled when a session contains two channels.
Note Sweep mode is available on PXIe-4190 device when operating in LCR mode. To change to LCR mode, go to the Channel settings within the device panel, click the Mode drop-down, and select LCR meter.

Channel Operating Modes

In addition to device operating modes, you can also specify an operating mode for each channel. Some channel operating modes are only available on devices with certain capabilities.

If you change the operating mode of a channel, all panel measurements are paused. Any enabled outputs continue to generate signal at the last configured level. The new operating mode of the channel will not take effect until you run the panel.

  • Idle—The channel is not programmed. If you change a channel to Idle from another mode, the channel continues to generate signal according to its last configuration.
  • Voltage or Current—Sources DC voltage or DC current at a single configured level while the output is enabled.
  • Pulse voltage or Pulse current—Generates a single pulse at the pulse level, then returns to the bias level.
    Note
    • For more information on pulsing and devices that support pulse measurements, refer to Pulsing in the NI-DCPower help.
    • InstrumentStudio currently supports single point pulsing only; InstrumentStudio 2019 does not support pulse sequencing.
  • Voltage sequence or Current sequence—Allows you to configure a level and a duration for each step in a list. You can configure the list of steps on the device panel, or import steps from a .CSV file. For more information on creating voltage or current sequences, refer to Configuring Sequences.
    Note
    • If you import a step sequence from a .CSV file, the .CSV file must have two columns: the first for the level, and the second for the duration.
    • Voltage sequence and Current sequence modes are not available on the PXI-4110, PXIe-4112, PXIe-4113, PXI-4130, or PXI-4132 devices.

SMU Measurement Autorange

When the range for a signal is unknown, using measurement autorange enables the signal range to be automatically determined.

When a measured signal exceeds the specified range in InstrumentStudio, InstrumentStudio will not be able to accurately measure that signal, and will warn you that the measurement is over range. When you enable measurement autorange, InstrumentStudio uses incoming signal data to automatically set measurement ranges, ensuring more accurate measurements.

Enabling Autorange

  1. To enable autorange mode for an SMU or VPS device, click the Measurement Autorange toggle within the device panel and ensure it is in the On position.
  2. Optional: Use the device panel to configure autorange settings.
  3. Optional: To disable autorange, click the Measurement Autorange toggle again and ensure it is in the Off position.

Configuring Autorange

Use the following controls in the SMU or VPS device panel to specify how you want autorange to respond to incoming signals from your device.
Note Autorange mode must be enabled to access these settings in your device panel.
  • Aperture time mode — Specifies whether the aperture time used for measurement autorange is determined automatically or customized using the value specified by the Minimum aperture time setting.
  • Minimum aperture time — Specifies the aperture time used by the measurement autorange algorithm.
    Note This is a minimum value, and will be scaled up to optimize the algorithm for different ranges. For smaller ranges, the value will be scaled up to account for signal noise.
  • Minimum aperture time units — Specifies the units of the Minimum aperture time setting. Aperture time can be specified in seconds or power line cycles (PLCs).
  • Autorange behavior — Specifies the algorithm the hardware uses for measurement autoranging. Choose from the following behaviors.
    • Range up to limit then down — go to range limit the range down until measured value is within thresholds.
    • Range up — go up one range when upper threshold is reached.
    • Range up and down — go up or down one range when the upper or lower threshold is reached.
  • Minimum current range — Specifies the lowest range used during measurement autoranging.
    Note Limiting the lowest range can improve the speed of autoranging and minimize thrashing between ranges when measuring a noisy signal.

NI-DCPower Independent Channel Sessions

InstrumentStudio creates a single multi-channel session for all devices in a single SMU device by default.

Note This is not default behavior in some versions of InstrumentStudio.

Considerations when configuring sessions with SMU devices

Using independent channels allows you to configure multiple channels of the same instrument, or multiple instruments, within the same session independently of one another. InstrumentStudio exports a single session configuration for all channels by default. In certain cases, you must change your session type to Single channel (compatibility) mode.

Note To manually select the session type you want to use, open the instrument header menu () of the device in your panel, and click Session Type.

You should select Session Type » Single channel (compatibility) when:

  • Exporting a session to platforms which do not support NI-DCPower independent channel sessions. These include Python, LabWindows/CVI, LabVIEW NXG, and Linux desktop.
  • Exporting a session to NI-DCPower version 20.5 and earlier.
  • Exporting the session to end-user code which uses deprecated NI-DCPower Initialize Functions in C/LabVIEW or deprecated constructors in .NET.
  • Note Exports from sessions created in InstrumentStudio with independent channels cannot be imported into sessions created with single channels. To verify your session channel configuration, go to the instrument header menu () and click Session Type.

Output Status

You can determine the current output status of non-idle channels with the output status icon, located at the top of the Channels section of an SMU/Power Supply panel.

Table 2. SMU/Power Supply Channel Output Status
Icon Status Description


Generating Output One or more channels in the panel are sourcing voltage or current.


Not Generating Output No channels in the panel are sourcing voltage or current.


Waiting for Trigger Channels in the panel are waiting until the trigger condition has been met to start an operation.


Unknown Status The output status of the channel(s) in the panel is unknown. Run the panel to refresh the output status.
Note Output continues when closing a panel.

Configuring SourceAdapt Parameters to Measure Transients

You can use SourceAdapt technology to customize the source measure unit (SMU) response to any load. For more information on National Instruments' SourceAdapt technology, refer to NI SourceAdapt Next-Generation SMU Technology on ni.com.
Note Not all SMUs support SourceAdapt technology. Refer to the documentation for your SMU to see whether the SMU supports SourceAdapt.
Selecting a SourceAdapt Preset
  1. Place a SourceAdapt-compatible SMU in the large panel.
  2. Place the SMU panel into Waveform mode.
  3. Open the Channel Settings window.
  4. Scroll down to the SourceAdapt tuning parameters section of the Channel Settings window.
  5. Select a SourceAdapt preset from the list:
    • Slow—Slows the control loop for a more stable response.
    • Normal—The default SourceAdapt preset, a balance between speed and stability.
    • Fast—Speeds up the control loop for a faster response.
  6. (Optional) Make custom adjustments to the response using the fields in the SourceAdapt tuning parameters section.

Configuring Sequences

You can change the channel operating mode of an SMU/Power Supply channel to Voltage Sequence or Current Sequence mode to enable power sequencing. Power sequencing allows you to output the desired power-up sequence for a DUT with multiple power sources by configuring the order, timing, and level of each power supply channel.

Note
  • Channels within the same panel operating in Voltage Sequence, Current Sequence, Pulse Voltage, or Pulse Current mode are automatically hardware-synchronized. Refer to Multi-Device Synchronization for more information on hardware and software synchronization within panels.
  • Sequence channel operating modes are supported only on power supplies that support advanced sequencing. For more information on advanced sequencing and supported devices, refer to NI-DCPower Advanced Sequencing documentation.
  1. Place an SMU or power supply in a panel.
    If you place the device in a large panel, the graph shows a preview of the output sequence the channel will generate.
  2. Set the operating mode of the panel to Waveform or Charting.
    Placing the panel in Waveform mode enables fast sampling and allows you to visualize the sequence in more detail.
  3. Set the channel operating mode to Voltage sequence or Current sequence.
    A step table appears within the channel.
  4. Edit the steps in the step table by entering the values manually, importing data from a file, or pasting data from the clipboard.
  5. (Optional) Tune the output of the sequence using SourceAdapt parameters, found in the Channel Settings window.
  6. Enable the channel output and run the panel to begin the sequence.