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IviScope Fetch Min Max Waveform [MmW] (G Dataflow)

Version:
    Last Modified: October 24, 2017

    Returns the minimum and maximum waveforms that the oscilloscope acquires for the channel you specify.

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    initial x

    Indicates the time of the first point in the Min Waveform Array and Max Waveform Array. The time is relative to the trigger event. For example, if the oscilloscope acquires the first point in the waveforms 1 second before the trigger, this parameter returns the value -1.0. If the acquisition of the first point occurs at the same time as the trigger, this parameter returns the value 0.0. Units: seconds

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    actual points

    Value that indicates the number of points the node places in the Min Waveform Array and Max Waveform Array parameters.

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    x increment

    Value that indicates the length of time between points in the Min and Max Waveform Arrays. Units: seconds

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    max waveform array

    Returns the maximum waveform that the oscilloscope acquires. Units: volts

    Associated Nodes

    IviScope Actual Record Length Returns the number of points the oscilloscope acquires for each channel.
    IviScope Configure Interpolation [I] Configures the interpolation method the oscilloscope uses.
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    Note  

    If you disable interpolation, the oscilloscope does not interpolate points in the waveform. If the oscilloscope cannot sample a value for a point in the waveform, the driver sets the corresponding element in the Waveform Array to an IEEE defined NaN (Not a Number) value and the VI returns IVISCOPE_WARN_INVALID_WFM_ELEMENT (0x3FFA2001).

    IviScope Is Invalid Waveform Element Tests a waveform value for an invalid value condition.
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    min waveform array

    Returns the minimum waveform that the oscilloscope acquires. Units: volts

    Associated Nodes

    IviScope Actual Record Length Returns the number of points the oscilloscope acquires for each channel.
    IviScope Configure Interpolation [I] Configures the interpolation method the oscilloscope uses.
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    Note  

    If you disable interpolation, the oscilloscope does not interpolate points in the waveform. If the oscilloscope cannot sample a value for a point in the waveform, the driver sets the corresponding element in the Waveform Array to an IEEE defined NaN (Not a Number) value and the VI returns IVISCOPE_WARN_INVALID_WFM_ELEMENT (0x3FFA2001).

    IviScope Is Invalid Waveform Element Tests a waveform value for an invalid value condition.
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    waveform size

    Value representing the expected size of the waveforms that the oscilloscope acquires. That value is greater than or equal to the minimum number of points you specify in the IviScope Configure Acquisition Record Node.

    Determining Waveform Size

    Default: 1000

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    channel name

    String you pass to represent the virtual channel name that you assign to the instrument in the Configuration Utility from which you want to read the minimum and maximum waveforms. This control accepts virtual channel names you have assigned to the specific instrument you are using. It also accepts the instrument-specific channel names.

    Achieving Interchangeability

    Virtual Channel Names

    The virtual channel name should be sufficiently specific to the test system such that it is unlikely to conflict with a physical channel name. Virtual channel names are aliases for instrument-specific channel strings. The instrument-specific channel strings can differ from one instrument to another. Virtual channel names allow you to use and swap instruments without having to change the channel names in your source code. You assign a virtual channel name to an instrument-specific channel through the Configuration Utility.

    Default: "CHANNEL1"

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    instrument handle out

    The instrument handle that you obtain from the IviScope Initialize or IviScope Initialize With Options node. The handle identifies a particular instrument session.

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    instrument handle

    The instrument handle that you obtain from the IviScope Initialize or IviScope Initialize With Options node. The handle identifies a particular instrument session.

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    error out

    Error information.

    The node produces this output according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.
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    error in

    Error conditions that occur before this node runs.

    The node responds to this input according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Default: No error

    Channel Not Enabled Error

    If the channel is not enabled for the acquisition, this function returns the IVISCOPE_ERROR_CHANNEL_NOT_ENABLED (0xBFFA2001) error.

    Invalid Acquisition Type Error

    This node fetches waveforms when you set the acquisition type to IVISCOPE_VAL_PEAK_DETECT or IVISCOPE_VAL_ENVELOPE. If the acquisition type is not one of the listed types, the node returns the IVISCOPE_ERROR_INVALID_ACQ_TYPE (0xBFFA2004) error.

    Obtaining Min/Max Waveforms

    Use the IviScope Initiate Acquisition Node to start an acquisition on the channels that you enable with the IviScope Configure Channel Node. The oscilloscope acquires the min/max waveforms for the enabled channels concurrently. You use the IviScope Acquisition Status Node to determine when the acquisition is complete. You must call this node separately for each enabled channel to obtain the min/max waveforms.

    The waveforms are from an acquisition that you previously initiated. You can call the IviScope Read Min Max Waveform [MmW] Node instead of the IviScope Initiate Acquisition Node. The IviScope Read Min Max Waveform [MmW] Node starts an acquisition on all enabled channels, waits for the acquisition to complete, and returns the min/max waveforms for the channel you specify. You call this node to obtain the min/max waveforms for each of the remaining channels.

    Configuring Interpolation

    You configure the interpolation method the oscilloscope uses with the IviScope Is Invalid Waveform Element Node. If you disable interpolation, the oscilloscope does not interpolate points in the waveform. If the oscilloscope cannot sample a value for a point in the waveform, the driver sets the corresponding element in the Waveform Array to an IEEE defined NaN (Not a Number) value and the node returns IVISCOPE_WARN_INVALID_WFM_ELEMENT (0x3FFA2001).

    Min/Max Waveform Array

    After this node executes, each element in the Min Waveform Array and Max Waveform Array parameters is either a voltage or a value indicating that the oscilloscope could not sample a voltage.

    Testing for Invalid Conditions

    You can test a waveform value for an invalid value condition by calling the IviScope Is Invalid Waveform Element Node.

    Checking Instrument Status

    This node does not check the instrument status. Typically, you call this node only in a sequence of calls to other low-level driver nodes. The sequence performs one operation. You use the low-level nodes to optimize one or more aspects of interaction with the instrument. If you want to check the instrument status, call the IviScope Error-Query Node at the conclusion of the sequence.

    Simulated Waveforms

    The class driver returns a simulated minimum and maximum waveform when this node is called and the IviScope>>Inherent IVI Settings>>User Options>>Simulate property is set to TRUE and the IviScope>>Inherent IVI Settings>>User Options>>Use Specific Simulation property is set to FALSE. For information on how to configure a simulated waveform, refer to the online help manual.

    Extension Group

    This node is part of the IviScopeMinMaxWaveform [MmW] extension group.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: Not supported

    Web Server: Not supported in VIs that run in a web application


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