Which variable have the information that the hardware stop trigger came, in double-buffered functions.

[AVI]

I'm reading continuous I/O data with 653x board, using the double-buffered functions, I start the acquisition with hardware trigger and I want stop the acquisition with hardware trigger too. For do the acquisition I use a repeat loop, when the stop trigger come the NI-DAQ stop the acquisition and I don't know what variable can I read for exit from the loop and go to the show window, in other words, which variable have the information that the hardware stop trigger came.

[aasenjo]

AVI,

Since you don't mention the development environment you are using so it is a little difficult to be specific about your options. Basically, NI-DAQ has been designed so that once you get the stop condition, the driver stops acquiring data and does not put anything else in the application buffer.

Once your application has read in all the data received before the stop condition, you will find that no newer data is being returned by your read function, and you can use this as a sign that you may exit the acquisition loop. Normally an error code is returned in text-based environments. In LabVIEW, the Read VIs contain an output terminal that indicates that the Acquisition has been completed.

Regards,

Alejandro Asenjo
Applications Engineer
National Instr
uments

[aasenjo]

As the customer further revealed, via email, he was using Delphi 5 implemented the solution by looking for the specific noTransferInProgError error code returned by the DIG_DB_HalfReady function in the acquisition loop. Once the error code was received the application would exit from the acquisition loop.

Regards,

Alejandro Asenjo
Applications Engineer
National Instruments