Streaming data from multiple High Speed Digitizer Modules

[ninjaphil]

Please provide feedback, comments, and questions on the Streaming data from multiple High Speed Digitizer Modules Reference Design in this thread.

[arrowcq]

One of our customer need to use C#  to programme scope streaming function:

hardware: PXIe-8130 PXIe-8265, double PXIe-5122

Configuration： 4 channel @ sample rate 100MBPS

can your reference code be easily transfered to C# enviroment?

[kalyanramuv]

The acquisition and writing disk part can be reused from the C code in the above document. However, you would have to modify the user interface code according to your needs.

[FredEm]

I am very interested with this example. i will have to adapt it. But i don't understand how it is possible to reach 600Ms/s after my tests.

When i tested 2 examples from NI "Fetchforever" (5.8e6 fetched point instead of 1.2G that is the memory of the 5185 card) and  "Multi Record Fetch More Than Available Memory", at 312Ms/s, it seems that speed fetch is too low to follow records acquired.

Ideally for my application I would like to set up a continuous multi-record acquisition on the PXIe-5185 using external trigger. In other words, its an infinate record acquisition.

For example: I would acquire 4096 samples (this is record length) at about 4 KHz at 312.5 Ms/s sampling rate. This would go on and on using the "more than available memory option" so as to keep overwriting the memory cyclically.

So i will have to adapt this example, but i don't understand why the exemples does not work at 300Ms/s...! I started to code it but i have the same probleme : after 500 000 records, acquired records not fetched are more than 100 000. I tried with the external PC and it is the same problem than with the 8135 controller.

How is it possible to do streaming at 600Ms/s if at 300Ms/s, fetched record speed is too low !? At a moment, with this "fetch" speed, the memory is full and data are overwritten with an error or the 100 000 records not fetched are reached.

My setup :

NI PXIe-1075 where are plugged :

3 cards NI PXIe-5185 12.5G bits/s 8bits Memory : 512Mo per channel

1 Remote contrôle card NI PXIe-8381 linked to the PC

2 NI-8262 Expansion Module linked to the disks

- 2 NI RAID disks (5To each) linked in PXIe to the computer

- NI PXI-8135 2.26 GHz Quad-Core PXI Embedded Controller card.

- 1 external PC (windows 7, Intel(R) Xeon(R) CPU E5-1620 0 @ 3.60GHz, 3601 MHz, Quad-Core, 8 logical processors)