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Create Waveform (From File » HWS) (G Dataflow)

Last Modified: May 16, 2018

Takes waveform data from a specified Hierarchical Waveform Storage (HWS) file and creates an onboard waveform for use in arbitrary waveform or arbitrary sequence output modes.

The waveform generator must not be in the Generating state when you call this node.

Programming Patterns

You must set the output mode input of Configure Output Mode to arbitrary waveform or arbitrary sequence before calling this node.

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session in

Handle that identifies your instrument session previously allocated by Initialize With Channels.

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channel name

Name of the waveform generator channel that the node uses.

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file name

Full path and name of the file that contains the waveform data.

The data must be between -1.0 and +1.0. The 16-bit integer (I16) data value range of -32,768 to +32,767 is assumed to represent -1.0 to +1.0 volts. HWS files may contain 16-bit integer (I16) or double-precision floating-point (DBL) data, depending on how they are saved.

You can use the gain input of Configure Arbitrary Waveform or Configure Arbitrary Sequence to generate different voltages. Check the Scale Data to +/- 1V option if writing data from the Analog Waveform Editor to ensure your data is between -1.0 and +1.0.

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use gain and offset from waveform

Boolean value that specifies whether or not the gain and offset values from the specified HWS file should be applied.

You store the gain and offset values when you save an HWS file using the Analog Waveform Editor.

True The node retrieves the gain and offset values from the specified HWS file and applies them.
False The node does not apply the gain and offset values from the specified HWS file.

Default: True

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use rate from waveform

Boolean value that specifies whether or not the sample rate or I/Q rate from the specified HWS file should be applied.

You store the sample rate when you save an HWS file using the Analog Waveform Editor.

True The node applies the sample rate or I/Q rate from the specified HWS file.
False The node does not apply the sample rate or I/Q rate from the specified HWS file.

If you set this input to True and if onboard signal processing (OSP) is enabled, the rate from the waveform is interpreted as the I/Q rate, which causes the node to set the IQ Rate property for you. In all other cases, the rate from the waveform is interpreted as the sample rate, and this node sets the sample rate for you.

Default: True

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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

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session out

Reference to your instrument session to wire to the next node.

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waveform reference out

Reference that identifies the waveform.

This output can be used later for setting the active waveform, changing the data in the waveform, building sequences of waveforms, or deleting the waveform when it is no longer needed.

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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.

Setting Gain and Offset with Create Waveform From File (HWS)

If you use this node to set the gain and offset, you should not use Configure Arbitrary Waveform or Configure Arbitrary Sequence, as they also set the gain and offset, thereby overriding the values set by this node.

Instead, use Property Node to set the arbitrary waveform handle or arbitrary sequence handle properties.

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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