NI-HSDIO Express (Acquisition) VI

NI Digital Waveform Generator/Analyzer

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NI-HSDIO Express (Acquisition) VI

Acquires a digital waveform from a National Instruments digital waveform generators/analyzer.

Dialog Box Options
Block Diagram Inputs
Block Diagram Outputs

Dialog Box Options

ParameterDescription
ConfigurationContains the following options:
  • Device—Specifies the device used. Unavailable devices are disabled.
  • Enable HW Compare—Specifies whether this Express VI compares the acquired data to an expected response. Configure the expected response data source using the HW Compare tab.
  • Tristate channels before acquisition—Specifies whether configured channels that were previously left generating data are tristated.

    Checked: Configured channels previously left generating data are tristated.

    Unchecked: Configured channels previously left generating data are not tristated.

  • Channels—Displays the channels currently configured to acquire data.
    • Modify—Click Modify to launch the Select Channels dialog box.
  • Timing—Contains the following options:
    • Rate (Hz)—Specifies the Sample clock frequency for the acquisition.

      Units: Samples per second (S/s)

    • Samples to Read—Specifies the number of samples to acquire.
VoltageContains the following options:
  • Logic family—Specifies whether you configure your voltage levels using one of the predefined voltage families for this device.
  • Custom levels (V)—Specifies whether you configure custom high and low voltage thresholds for the acquisition. This feature is not supported on all devices.
    • High—Specifies the high voltage threshold for the acquisition. This feature is not supported on all devices.

      Units: volts (V)

    • Low—Specifies the low voltage threshold for the acquisition. This feature is not supported on all devices.

      Units: volts (V)
TriggerConfigures the trigger options. Contains the following options:
  • Reference trigger type—Specifies the Reference trigger type for the acquisition.
    If this control is set to None, the acquisition starts as soon as you run this VI. For all other values, the VI configures the device to wait for a trigger and returns the number of samples you configure in pretrigger samples immediately before the trigger and returns the remaining samples immediately after the trigger.

    If this control is set to Digital Edge, the following options are visible:
    • Max Time (s)—Specifies the Sample clock frequency for the acquisition.

      Units: Samples per second (S/s)

    • Pretrigger Samples—Specifies the number of pretrigger samples the device must receive before the Reference trigger is acknowledged. Of the total number of samples returned by the VI, the number of samples configured as pretrigger samples are acquired immediately prior to the trigger. The remaining samples are acquired immediately after the trigger.
    • Trigger Source—Specifies the trigger source. The digital waveform generator/analyzer waits for the specified trigger to start the acquisition.
    • Digital Edge—Specifies whether to trigger on a rising or falling edge of the trigger signal.

    If this control is set to Pattern Match, the following options are visible:
    • Max Time (s)—Specifies the Sample clock frequency for the acquisition.

      Units: Samples per second (S/s)

    • Pretrigger Samples—Specifies the number of pretrigger samples the device must receive before the Reference trigger is acknowledged. Of the total number of samples returned by the VI, the number of samples configured as pretrigger samples are acquired immediately prior to the trigger. The remaining samples are acquired immediately after the trigger.
    • Pattern—

      Shows the currently configured pattern that activates the pattern-match trigger under the conditions specified in trigger when.

      The following list shows the characters you can use in your pattern string.

      X = Ignore the channel
      0 = Match on a logic 0
      1 = Match on a logic 1
      R = Match on a rising edge
      F = Match on falling edge
      E = Match on either edge

      Push the ... button to the right of the control to edit the pattern.

    • Trigger When—Specifies the conditions under which the trigger asserts.

      Data Matches Pattern means that the trigger asserts when the sampled pattern matches the pattern specified in pattern.

      Data Does Not Match Pattern means that the trigger asserts when the sampled pattern does not match the pattern specified in pattern.
Advanced TimingConfigures options used less frequently for timing. Contains the following options:
  • Clock Configuration—Contains the following options:
    • Sample clock source—Specifies the Sample clock source.
    • Reference clock source—Specifies the PLL reference clock source. The device phase-locks the Sample clock to the Reference clock signal to prevent the Sample clock from drifting relative to the Reference clock.
  • Data Position—Contains the following options:
    • Data position—Specifies which edge of the Sample clock signal is used to time the acquisition. You can also configure the device to acquire data at a configurable delay past each rising edge of the Sample clock.
    • Data position delay—Specifies the time after the rising edge of the Sample clock before data is acquired. Data delay is expressed as a fraction of the clock period.
HW Compare Contains the following options:
  • Expected Response Data—Contains the following options:
    • Data Source—Specifies whether the Express VI retrieves the data to generate from an .hws (Hierarchical Waveform Storage) file. Otherwise, data must be wired to the data input terminal.
    • Path—If Read from file is checked, use this control to specify the .hws file containing the data to generate.
    • Loop Count—Specifies the number of times to repeat the current finite waveform.
  • Results—Contains the following options:
    • BER—Enables bit error rate (BER) calculation. BER is calculated by taking the number of sample errors and dividing it by the total number of samples compared.
    • BER per channel—Enables bit error rate (BER) calculations for each configured channel. BER for an individual channel is calculated by taking the number of bit errors found for that channel and dividing it by the total number of samples compared.
    • Fault Locations—Enables the retrieval of the locations for the bits that were in error. Only the first 1,024 sample errors are returned.

Block Diagram Inputs

ParameterDescription
data Contains the expected response data for the comparison operation. data does not exist when you select the Read from File option in the NI-HSDIO Express (Acquisition) Results page.
closeDetermines whether the instrument session remains open when the VI finishes execution. Use this parameter for loop optimization by setting it to FALSE on all iterations other than the last iteration. close is TRUE by default.
Note  This input is not intended to be used to share the session between Express VIs. If you have a loop containing multiple Express VIs that use the same device, you must wire in TRUE for this input.
max timeSpecifies the timeout value for the Express VI.
error inDescribes error conditions that occur before this Express VI runs.

Block Diagram Outputs

ParameterDescription
data Contains the digital data acquired by the device.
passed Returns the pass/fail result of the last hardware comparison operation.
number of sample errors Returns the number of sample errors found in the last hardware comparison operation.
BER Returns the bit error rate (BER). BER is calculated by taking the number of sample errors and dividing it by the total number of samples compared.
BER per channel Returns the bit error rate (BER) for each channel. BER for an individual channel is calculated by taking the number of bit errors found for that channel and dividing it by the total number of samples compared.
error locations Returns the bit numbers and the bit locations that were in error for each sample that has an error.
error outContains error information. If error in indicates that an error occurred before this Express VI ran, error out contains the same error information. Otherwise, it describes the error status that this Express VI produces.

This Express VI uses the functionality of the following VIs and functions:

niHSDIO Init Acquisition Session
niHSDIO Tristate Channels
niHSDIO Assign Dynamic Channels
niHSDIO Configure Sample Clock
niHSDIO Configure Voltage
niHSDIO Configure Acquisition Size
niHSDIO Configure Data Position
niHSDIO Configure Data Position Delay
niHSDIO Configure Ref Clock
niHSDIO Configure Trigger
niHSDIO Read Waveform
niHSDIO Close

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