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IviDigitizer Query Min Waveform Memory (G Dataflow)

Last Modified: October 24, 2017

Determines the minimum amount of memory that is needed to fetch or read data from the digitizer with maximum performance. The returned value includes the memory needed to handle DMA alignment issues and any internal memory that is used by the digitizer hardware or the driver. The parameters to this node are similar to the parameters used in Read and Fetch VIs. Users should call this node before allocating data buffer memory, and then call a Read or Fetch Node with the same parameter values. Notes: This node will return a value that can be used to allocate the optimally-sized memory buffer for Read and Fetch calls with the same passed parameters. If the Read and Fetch calls specify fewer data points, the data buffer will still be large enough and no performance penalty will be realized (aside from wasted memory space). If the Read and Fetch calls specify more data points they will simply fill the allocated memory buffer as fully as possible. Subsequent Fetch calls can then be made to retrieve the remaining data.

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Numer of Points Per Record (256)

Specifies the number of data points to return. Default Value: 256

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Number of Records (1)

Specifies the number of records that will be read. Default Value: 1

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Numer of Samples

Returns the minimum buffer size in samples needed for a subsequent Read or Fetch call with the same readout parameters.

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Data Width (Real64)

Specifies the size of the sampled data that will be retrieved. The value of this parameter must be 8, 16, 32 or 64, corresponding to the intended Read/Fetch VI. Valid Values: Int8 - 8 Int16 - 16 Int32 - 32 Real64 - 64 Default Value: 64

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Offset Within Record (0)

Specifies the start index within the record from which the data should be retrieved. Unit: volts Default Value: 0

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instrument handle out

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

Default: None

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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

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instrument handle

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

Default: None

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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