suggestions for high-speed DAQ with triggering

[faustina]

I want to take 2 channels of data at 1 mega-samples/sec each. I would prefer to use Digital Reference triggering. The problem is it could be up to 2 hours before I receive the trigger. Is it even possible to have a big enough buffer for this situation given this hardware: PXIe-1075 chassis, PXIe-6368 card, and PXI-6133 card? Should I consider different triggering or different hardware?  I'm using LabVIEW 2016.

The current error I'm receiving is:

Error -200361 occurred at Sync DAQ only.vi

Possible reason(s):

Onboard device memory overflow. Because of system and/or bus-bandwidth limitations, the driver could not read data from the device fast enough to keep up with the device throughput.

Reduce your sample rate. If your data transfer method is interrupts, try using DMA or USB Bulk. You can also use a product with more onboard memory or reduce the number of programs your computer is executing concurrently.

Task Name: _unnamedTask<1A>

[Kevin_Price]

Can you post the code for how you've configured this task?

While researching to test my thoughts on how reference triggering works, I came across some fairly in-depth details here.  Despite its age, I expect it's still pretty relevant.

You're likely in a situation where there should be continuous DMA transfer of data from the board to the task buffer at the application level.  All the business of circular buffering seems to be handled in the task buffer by the driver.  (It isn't quite clear to me though how the board indicates to the host PC exactly *when* the reference trigger condition occurs.)

The error you see is saying that the board can't move data off the board fast enough.  That's surprising because DMA and PCI-express are *easily* capable of 2 channels at 1 MHz.

Do you have a controller in the PXI chassis or are you using some kind of remote connection such as MXI?  Is there other high-bandwith activity occupying the data bus?

-Kevin P