NI-DAQmx .NET Framework 4.0 API Reference

AnalogSingleChannelReader.BeginReadWaveform Method (TimeSpan, AsyncCallback, Object)

Download PDF

Updated2023-02-21
2 minute(s) read

Begins an asynchronous read of one or more analog waveform samples from a single AIChannel object in a task for a specified duration.

Namespace: NationalInstruments.DAQmx
Assembly: NationalInstruments.DAQmx (in NationalInstruments.DAQmx.dll) Version: 20.7.40.49302

Syntax

public virtual IAsyncResult BeginReadWaveform(
	TimeSpan duration,
	AsyncCallback callback,
	Object state
)

Public Overridable Function BeginReadWaveform ( 
	duration As TimeSpan,
	callback As AsyncCallback,
	state As Object
) As IAsyncResult

Parameters

duration: Type: SystemTimeSpan
The duration of time to read the waveform. The duration specified must be long enough to read at least one sample at the configured SampleClockRate.
callback: Type: SystemAsyncCallback
An optional asynchronous callback that is called when the read is complete. Specify if you do not want a callback when the read is complete.
state: Type: SystemObject
A user-provided object that distinguishes this asynchronous read request from other requests. Use this parameter to provide information to the callback. Specify if you do not need to pass any additional information to the callback.

Return Value

Type: IAsyncResult
An IAsyncResult that represents the asynchronous call.

Remarks

To get the read data or any exceptions that occurred during an asynchronous read initiated with BeginReadWaveform(TimeSpan, AsyncCallback, Object), call EndReadWaveform(IAsyncResult), passing the returned IAsyncResult.

NI-DAQmx scales the read data to the units of the measurement, including any custom scaling you apply to the channel. You specify these units when creating channels using the create channel methods or the DAQ Assistant.

The data returned from analog waveform reads is affected by the WaveformAttributeMode property of the DaqStream being read.

NI-DAQmx read and write methods time out after the amount of time specified by the Timeout property on the Stream object used for the reads or writes.

Refer to NI-DAQmx Readers and Writers for more information about memory limitations in NI-DAQmx read methods.

Note
Refer to Asynchronous Reads and Writes for additional information.

NI-DAQmx .NET Framework 4.0 API Reference

Table of Contents

AnalogSingleChannelReader.BeginReadWaveform Method (TimeSpan, AsyncCallback, Object)

Syntax

Parameters

Return Value

Remarks

See Also

Reference

Other Resources

Log in to get a better experience