Using 6534 onboard memory only

[Oli_Wachno]

Hi there,

I'm trying to set up a small pattern generator / analyzer using an PXI 6534 (DAQmx 7.5). Synchronizing the two groups for IO is no problem, but how do I make shure that in- and output operations use only onboard memory (provided that the pattern does not exceed 32MB). I found a property node option for Digital Output operation called DO.UseOnboardMemory, but I could not find the equivalent for Digital Input.

Can anyone help me?

Cheers

Oli

[Andre_Saller]

DO.UseOnboardMemory set to true means, that any pattern you write to the task is written directly into OnboardMemory. If set to false the pattern would be written to some memory-space on your computer, and the driver would transfter this data to the onboard-memory afterwards, whenever he needs the data.

For Digital Input no such mechanism is available. the driver will take care that no data is lost, using as many OnBoard memory as needed to buffer the data, and tranfer the data to the memory space of your machine in buffered mode.

[Oli_Wachno]

Thanks for the reply,

I tried the DO.UseOnboardMemory with unexpected results. If my interpretation is right, I should be able write an 16 Bit wide pattern with up to 2 MSamples to the onboard RAM and after that start an output operation at max 20MHz (20MS/s).

This unfortunately gives me a buffer underflow error at a pattern that has only 128 samples....

I might be able to meet you at the VIP to show you the code. That might help 🙂

Cheers

Oli