cRIO scan mode high speed sampling

[MartinP]

I'm trying to sample data at 200 Hz during some few seconds, see below. When I'm not in need of the data, the loop goes at 2 Hz.

The hardware is a cRIO-9074. Problem is that the CPU goes at 100% during sampling. I have tried storing to file instead of these

FIFO Shared Variables, but with the same results. The Scan Engines Scan Period is set to 5 ms.

When I'm not logging, CPU is at about 25%. See attachment for source code.

Anybody got good suggestions about trimming the system, or other ways to dealing with the problem ?

Martin

[GerdW]

Hi Martin,

the cRIO ScanEngine is not the best when it comes to "high-speed DAQ"...

Additionally you're dealing with a lot of network-shared variables. Both parts of your VI take their time and will limit iteration speed (plus take their share of CPU time).

You can:

- use parallel loops for DAQ and network access

- limit the number of SVs by combining your DAQ data into an array or a cluster. Using a cluster you can also include timestamp data in it...