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XNET Write (Signal » Waveform) (G Dataflow)

Last Modified: November 2, 2017

Writes data to a session of Signal Output Waveform mode. The data represents a waveform of resampled values for each signal in the session.

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session in

The session to write. This session is selected from the LabVIEW project or returned from XNET Create Session. The session mode must be Signal Output Waveform.

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data

An input that provides a one-dimensional array of LabVIEW waveforms. The data you write is queued up for transmit on the network. Using the default queue configuration for this mode, and assuming a 1000 Hz resample rate, you can safely write 64 frames if you have a sufficiently long timeout. To write more data, refer to the XNET Session Number of Values Unused property to determine the actual amount of queue space available for writing.

Each array element corresponds to a signal configured for the session. The order of signals in the array corresponds to the order in the session list.

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t0

The waveform start time. This is a LabVIEW absolute timestamp.

This start time is unused (reserved) for Signal Output Waveform mode. If you change it from its default value of 0 (invalid), XNET Write (Signal Waveform) returns an error.

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dt

The waveform delta time. This is a LabVIEW relative time that specifies the time between each sample in the Y array.

LabVIEW relative time is represented as 64-bit floating point in units of seconds.

This delta time is unused (reserved) for Signal Output Waveform mode. If you change it from its default value of 0, XNET Write (Signal Waveform) returns an error.

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Y

The array of resampled signal values. Each signal value is scaled, 64-bit floating point.

The Y array size must be the same for all waveforms, because the size determines the total timeline for XNET Write (Signal Waveform). If the Y array sizes are not the same, XNET Write (Signal Waveform) returns an error.

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timeout

The time to wait for the data to be queued for transmit. The timeout does not wait for frames to be transmitted on the network (refer to XNET Wait (Transmit Complete)).

The timeout is a LabVIEW relative time, represented as 64-bit floating-point in units of seconds.

If timeout is positive, XNET Write (Signal Waveform) waits up to that timeout for space to become available in queues. If the space is not available prior to the timeout, a timeout error is returned.

If timeout is negative, XNET Write (Signal Waveform) waits indefinitely for space to become available in queues.

If timeout is 0, XNET Write (Signal Waveform) does not wait and immediately returns an error if all data cannot be queued. Regardless of the timeout used, if a timeout error occurs, none of the data is queued, so you can attempt to call XNET Write (Signal Waveform) again at a later time with the same data.

This input is optional. The default value is 10.0 (10 seconds).

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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

An output that is the same as session in, provided for use with subsequent nodes.

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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.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Supported

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


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