NI-6561 Stream to disk

[Modugno]

Hi,

I am currently using the NI-6561 and I want to stream to disk a 32,57MHz LVDS signal. I need to store only two of its 16 channels. I already read everything I could found about the NI-HSDIO but I couldn´t find a way to do continuous aquisition.

Thanks in advance,

Rodrigo Modugno

PS: I am using the NI-6561 with 2MB onboard memory

[Timothy 123]

Hi,

I have a pxi 6561 as well. For streaming to disk, have you looked at the continuous acquisition example with the new nihsdio driver. I belive this was not in the previous version 1.3 of the nihsdio driver. This example allows you to stream in data into the pxi 6561 from a device under test. Our pxi 6561 was in a pxi chassis and we were able to stream up to 50 MHz or 50MB/s of data using a fast computer with the 6561 in a pxi chassis with a mxi -4 connection. The streaming is highly dependent upon the computer as I had tested this on a slower computer and it was much slower.

-Tim

[Modugno]

Hi Tim,

I downloaded the new NI-HSDIO driver and I could test the streaming to disk sample. I could stream up to 8MHz, which is useless as I was trying to reach 32MHz. I´m using an Advantech Industrial FSBC with a 2.4GHz pentium 4 processor and 1GB of DDR/266 ram. I asked advantech for a faster board (and memory) and I´m gonna try it to see how fast it can get. Which computer have you used in your tests?

Thanks,

Rodrigo

[Timothy 123]

Hi,

I used a duall processor dell xps xeon computer. It is at 3.4 Ghz with 2GB of memory. also, if you have other things in your pci bus, performance will be slow since resources are shared on all the devices on the pci bus.

-Tim

[Timothy 123]

Hi,

Another thing is you might want to decrease the data width to be one byte since you only need 2 of the 16 channels, and also for reference we have the 16 Mb version of this card.

-Tim

[Modugno]

Tim,

As far as I know, the 6561 works only with 2byte wide data. I tried to set it with 1byte data width but I couldn´t, as it returns an error when fetching data. Is there a workaround to solve it?

Rodrigo

[Timothy 123]

Hi,

When you have one byte data width, you can only acquire on channels 0 through 7, the first 8 channels. Are you acquiring on any of the channels from 8 to 15. What is the error message by the way.

-Tim

[ryanm]

Hi Tim and Rodrigo,

We have discovered an issue with acquisitions using the 6561/2 in single data rate mode with a datawidth=1 byte.  When this configuration is used, the acquired data will be an array of 0's.  We are working to resolve this issue as fast as possible.  This issue will be fixed in a future HSDIO driver.  If you need to acquire data using the 6561/2 in single data rate mode with a datawidth=1 byte, please send me your email address and I will be glad to discuss potential solutions with you.

Thanks,

Ryan

[Modugno]

Hi Ryan,

That would be good if I could set datawidth to 1byte as I would decrease the amount of allocated memory and it won´t be necessary to convert the captured data to an 8bit integer. But if you say that using 1byte the aquisition won´t speed up, then I'm not sure if it will be necessary. If you could mail me, my e-mail is modugno@opto.com.br.

Thanks,

Rodrigo

[Phone Thet Khaing]

Hi,

   Did you all manage to stream the data at 50MHz? I am curious as I am now facing the same problem, pls help if u can, my email address is tkphone@ntu.edu.sg,

Thanks a lot,