PXI-6115 Circular Buffer Problems

[nealpederson]

I have a PXI system with five PXI-6115s that I am trying to setup for fast
(i.e. 10MS/s each channel) sampling after receiving a trigger. I am setup
to acquire pre-trigger data so an internal circular buffer is required. The
problem I am having is that if enough time goes by for the 6115s to acuire
more than 2M samples of data before receiving a trigger I get the following
Error: Error -10845 at AI buffer Read, system and/or bus limitations. This
only happens when I am using more than one 6115, a fast sampling rate, and
multiple samples. It looks like the system is not creating a circular
buffer within the PXI-6115 memory but trying to do it over the PCI bus which
does not have the bandwidth for the number of channels that I am using. It
needs to happen withing each PXI-6115 using the onboard memory.

After searching around NI's website I did find something that appeared to be
very applicable to my problem:
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/30326d1ad48d86e086256e8e00245e48?OpenDocument

According to the document I chose the allocate device memory option as the
allocation mode in the AI Config.vi. After making this change I got the
following errors:

1. If setup for no pretrigger: results in an Error -10403 The specified
device does not support the requested action.

2. If setup for pretrigger results: in an Error -10608 No transfer is in
progress for the specified resource.

Does anyone else have similar experiences or solutions to my problem? I
have submitted this to NI (SR# 7063001) but they have not yet solved the
problem.

Thanks - Neal.