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Datasheets and User Guides

App Notes

Software & Driver

 

2.4 - Stream Functions

To stream an unlimited number of scans from a device:

  1. Initialize stream, allocate memory, and start a stream using LJM_eStartStream
  2. Repetitively read from the device stream using LJM_eStreamRead
  3. End the stream and free memory using LJM_eStreamStop

To stream a finite number of scans, use LJM_StreamBurst.

Data Movement

After starting stream:

  1. The device collects samples at the given scan rate in a buffer on the device.
  2. LJM collects samples from the device in a buffer within LJM.
  3. LJM_eStreamRead or LJM_eStreamBurst reads those samples from the LJM buffer.

3 comments

Is it possible to stream data out using LJM library (e.g. with LabView)? If so, could you provide a simple example e.g. how to stream out a square wave with LabView (from DAC0)? Thank you in advance.

Yes, you can stream out certain outputs such as the DAC lines using the LJM library. We document that here in the T7 datasheet:

http://labjack.com/support/datasheets/t7/communication/stream-mode/strea...

There is a general stream out example section on that page. It demonstrates what names/registers to write to for configuration. As for code examples, we currently only have a stream out example (o_stream_run) for C/C++ and Python. It looks like our LabVIEW examples currently do not have an example like this but we will look into adding one. All LJM code example downloads can be found here:

http://labjack.com/support/ljm/examples

There is now a stream example with stream-out in the LabVIEW_LJM archive.