PCI 5112 and fetch more than available memory

[wenatWayne]

Would anyone confirm that  pci 5112 can run fetch more than available memory vi with a large number of records(more than onboard memory)? Mine appears not able. thanks.

[James-B]

Hello,

What symptoms are you seeing that lead you to believe that your 5112 cannot fetch more than available memory?

Do they match anything listed in this knowledge base article?

http://digital.ni.com/public.nsf/allkb/9575F0EF6530B3BB862578D500713C2B?OpenDocument

[wenatWayne]

see attached screen shot. the error message is different from that in the cited article.

[James-B]

There is also a knowledge base article related to that error.  It basically says that this error is indicative of a driver crash and that you need to decrease the number of records to fetch.

http://digital.ni.com/public.nsf/allkb/F9DA62704E6B5F5E86257B4F004DD03D?OpenDocument

[wenatWayne]

Hi,

I have read that article too. does this mean 5112 can not run fetch more than available memory? As far as I understand, the large number of record does not require allocating  real memory when the fetch more than available memory option is activated. Therefore, it should not have such errors before the acquistion even starts. Since there is no obvious documents stating 5112 is not compatible with fetch more than available memory vi. I am wondering whether my card has some issue or firmware problem. can you verify this with other cards. thanks.

[James-B]

I tried it here and got the same error.  It seems like asking for 10M samples simply crashes the driver.  However, if you ask for 1M samples, you can see how the memory on the card fills up and throws an error after a few seconds.

So, in theory, you could ask for more records than availible memory for a bit.

[wenatWayne]

Hi Jim,

thanks for your verification. But 1M sample takes less than the on-board memory (16MB) while10M is over (2 byte per sample). so i don't know how you draw the conclusion: "So, in theory, you could ask for more records than availible memory for a bit.".

[James-B]

Yep, you're right.  I was looking at a different spec.

Then yes, it appears that the traditional DAQ driver can't handle requests for more records than memory.  I'll see if I can get that documented better.