NotifyWhenScansQueuedBelow
Control firing of DataRequired
event
Description
When working with the session-based interface to generate output
signals continuously, the DataRequired
event is
fired when you need to queue more data. This occurs when the ScansQueued
property drops below the value
specified in the NotifyWhenScansQueuedBelow
property.
Values
By default the DataRequired
event
fires when 1/2 second worth of data remains in the queue. To specify
a different threshold, change this property value to control when
the event is fired.
Example
Control When DataRequired Event Is Fired
Specify a threshold below which the DataRequired
event
fires.
Create a session and add an analog output channel.
s = daq.createSession('ni') addAnalogOutputChannel(s,'cDAQ1Mod2', 0, 'Voltage')
Queue some output data.
outputData = (linspace(-1,1,1000))'; s.queueOutputData(outputData);
Set the threshold of scans queued to 100
.
s.NotifyWhenScansQueuedBelow = 100;
Add an anonymous listener and generate the signal in the background:
lh = s.addlistener('DataRequired', ... @(src,event) src.queueOutputData(outputData)); startBackground(s);