high speed data between CRIO and HOST

[ern]

I am trying to view a signal obtained using an analogue input module (9215) on my CRIO. After having a lot of trouble with low sampling rates i read

Developing High Speed Continuous Buffered Data Acquisition Applications with CompactRIO

http://zone.ni.com/devzone/conceptd.nsf/webmain/8E999A74E43AC76186256F5E0068CFAC

Now i obtain around 600 s/s but this is still far too low. Please could someone give me some suggestions on how to increase the sampling rate.

Many Thanks.

my files -  http://www.formulastudent.strath.ac.uk/newsim.zip

[AdamB]

Hi ern,

(did you manage to solve your problems on this forum: http://forums.ni.com/ni/board/message?board.id=170&message.id=193189)

Well looking at the code it seems fine.

What values are you using for the sample rates etc?

I believe the loop function stalls the loop for the stated amount of time... so the higher the number the slower the program will go.

You'll probably find that your host machine is only executing 600 times a second and that is where your problem lies.

It might be worth looking into DMA transfer to get the information to your computer from the cRIO device.  What might be happening is that your host machine isn't querying the information on the cRIO quickly enough so you need a way of forcing the information to the host by way of DMA.

http://zone.ni.com/devzone/conceptd.nsf/webmain/0B5FF8ED662652EE8625708C00548ED8 this link is a good example of a simle DMA transfer program and should help you get started.

Hope this helps

AdamB

[ern]

Cheers this works fine. I had thought the VI i had before used DMA. Regarding the other post, that worked fine as well although i hope to move it more on to the host when i am more familiar with LV as i would like to make the signal far more complicated and be able to compare the outgoing signal to the incoming.

Thanks for your help

Ern

[rud]

Hello,

I have got a question in that case. I am using a cRIO plus a 9215-Module. The controller is reading data

form the 9215 directly through the FPGA (without FIFO) every 10 ms. The problem is, that there is no change in data for

about 150 ms, so approximatly 10-15 samples have the same value. It looks like the sampling rate of

the 9215 is much to low. How can I solve this?

Thanks,

Rudi