Timing of NI-9263 when USB-6343 used as master timing

[llobs]

Dear Madam/Sir,

 my experiment is using a USB-6343 as controller/acquisition card. As I need to add some more AO outputs to the system, I have the possibility to use a NI-9263 (with a USB connection - cDAQ-9171) to expand the present card to 8 AO.

My question is about making the NI-9263 timing slaved to the USB-6343 card:

- Is it possible to do it? I guess so, although the NI-9263 has not trigger input, through bus triggering

- How is good such synchronization?

- At the end, what I would like to obtain, is the output of 8 waveforms (4 from USB-6343 and 4 from NI-9263) with the same timing provided by USB-6343

- The driving software is developed in CVI.

Thanks

Regards

Luca

[bstreiff]

The cDAQ-9171/NI-9263 combination doesn't have a means to accept an external trigger input nor sample clock, so there's no way to synchronize it directly to a USB-6343 with any degree of confidence.

The best you'd be able to do is create two AO tasks (one with the 6343, one with the 9263) and try to start them at the same time, but the actual start times are going to be system-dependent. (If you want to go this route, I recommend using DAQmxTaskControl with DAQmx_Val_Task_Commit on both tasks before you start both tasks, to reduce the amount of overhead that occurs in DAQmxStartTask.)