Loop rate on my RT system not faster than 1kHz

[v1212800]

Hi,

I have a PXI5404 frequency generator card without memory. So I tried to program the memory list on my own with  while-loop. The value for the frequency card is updated with an extern digital signal. But it sems that my loop doesn't run faster thn 1ms. Is there any solution?
 I have a PXI system with an PXI 8176 Controller, an 6259 M-series card, a PXI 6723 analog out card and the frequency card.

Thanks for your help
Tim

[squared123]

I was unable to view your loop vi.  I take it that you have seen this web site: http://digital.ni.com/public.nsf/allkb/0c0a6ee528f85a6486256f6700061790  You might have to try pipelining in the FPGA to get the speed that you need.

[v1212800]

Thanks for the answer.

I have an PXI8176 controller, but also with the timed loop, I dont get faster rates for one loop than 1 kHz.

Do I need extra hardware for programming with FPGA?

Thanks

Tim

[Jochen]

It looks like the driver can't update the frequency of the 5404 faster than 1 kHz. An FPGA won't solve this problem as it won't be able to generate 100 MHz sine waveforms. Sorry but I don't see a good solution for your application.

Jochen Klier
National Instruments Germany

[v1212800]

Thanks for the answer.

In deed, I was able to change my frequency faster, down to 200 microseconds. First I gave out a frequency of 20kHz, switched to 3 MHz for 200 µs and back to 20 kHz. So, the card can read the frequency faster, but after I switched back to 20 kHz, the frequency isn't updated any more. The card is missing one trigger. Could it be faster to communicate directly with the analog devices chip un the card via some hardware addresses?

Thanks

Tim