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PCI6534 with DAQmx - Error 200621 - OnBoard Memory Underlfow

Dear Klaus

Many thanks for this explanation.

Good to know that a delay can resolve the issue. My only problem is, that my application is testing thousands of devices a day in production so of course I have to avoid any unnecessary delay. Further I am executing several digital patterns (so performing several writes to the PCI6534) for every single device, so if I'd have to add a delay for each of them that would add up significant test time.

I don't actually need the full 20MHz or even 10MHz performance BUT I need something which runs stable for a production environment. So if the problem depends on the overall load of the PC production might run into the problem any time.

As I am trying to run a finite pattern I would expect the output of data only to start once the tranfer of the whole pattern to the card has been finished. As this apparently is not the case for the code I use, isn't there any way to force such a behaviour (e.g. using properties)?

best regards

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Message 11 of 13
Hi Markus,
USA wrote:
"Even with the delay, the application should still be fine. You don't actually begin generating or acquiring data until after the delay and the samples will still be synchronized. With a finite application, the CPU peformance will not be as much of an issue as it was with my customer since their application was continuous. My customer had to worry about the possibility of Windows giving processor power to other programs in the middle of their program executing.

Right now, the delay is only 250ms. You could probably make this number even smaller. Also, with lower rates, the delay may not even be necessary. However, for high rates, a delay between the write and the start is the only way to solve this problem. The rates themselves will be system specific. Also, you are correct in that data is output after the transfer to the card is completed."

Best reagards
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Message 12 of 13

Dear Klaus

So I will try to upgrade to DAQmx 8.0 and try to insert some minimal delays.

many thanks for your support

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Message 13 of 13