ScopeChannelMeasurement.BeginRead Method

public IAsyncResult BeginRead(
	PrecisionTimeSpan timeout,
	long numberOfSamples,
	AnalogWaveformCollection<double> waveforms,
	AsyncCallback callback,
	Object asyncState
)

Public Function BeginRead ( 
	timeout As PrecisionTimeSpan,
	numberOfSamples As Long,
	waveforms As AnalogWaveformCollection(Of Double),
	callback As AsyncCallback,
	asyncState As Object
) As IAsyncResult

Parameters

timeout

Type: NationalInstrumentsPrecisionTimeSpan
The time to wait for data to be acquired. Using 0 for this parameter tells NI-SCOPE to fetch whatever is currently available. Using -1 for this parameter implies infinite timeout.

numberOfSamples

Type: SystemInt64
The maximum number of samples to fetch for each waveform. If the acquisition finishes with fewer points than requested, some instruments return partial data if the acquisition finished, was aborted, or a timeout of 0 was used. Use –1 for this parameter if you want to fetch all available samples. The method reads the actual record length and attempts to acquire all available samples. If it fails to complete within the timeout period, the method returns an error.

waveforms

Type: NationalInstrumentsAnalogWaveformCollectionDouble
The waveform object whose memory can be reused while creating the output waveform. To allocate memory during the call to this method, set waveforms to . The method will also allocate memory during the call if waveforms is set to a waveform object with zero-sized data or waveforms is set to a waveform object with a different size than that required for the output waveform. For example, if waveforms is set to a waveform object with the same size as that required for this method call, then no new memory is allocated for the output waveform, and instead the memory of the waveform object from waveforms will be reused for the output waveform.

callback

Type: SystemAsyncCallback
A delegate of type AsyncCallback, which will be invoked once the operation is complete.

asyncState

Type: SystemObject
The state of the asynchronous operation.

Return Value

Reference