RT global variable data transfer, RT parallel loops data transfer problem

[Aaziee]

Hi,

I am having a problem with data transfer on RT target using global or local variable.
My system configuration is:
128 AI channels (4 CRIO 9205) with 2000 Hz sampling rate.(I am using 3M FPGA and 9014 RT controller)
I am using DMA FIFO for data transfer from target to host (2 DMA FIFOS) and read 100 ms or 200 samples on RT host.
I need to transfer data to HOST PC for analysis.
I set up a TCP/IP connection between RT and PC. All works fine when I read from DMA FIFO and send data to the PC in the same loop .
What I want is to have a communication loop that runs in parallel with main loop and sends data to the PC.
I tried to transfer data from one loop to other using global or local variables but I have encountered a problem of data loss somewhere in that process.
My data loss is always on 200 -th, 400 -th etc.. point (I belive that it has something to do with reading blocks from FIFO??).
What can be the problem.

Thank you in advance!

[The Specialist]

Hi Aaziee,

I beleive what you want to do is read the data out of the DMA FIFO, and then place it into an RT FIFO.  The RT FIFO then passes the data to your TCP loop, which then sends it to your PC.  Since local variables do not retain historical data, you can possibly overwrite the data before you send it.  I hope that help.  The architecture is going to be very similar to producer/consumer.