Acquisition-Generation timing dependency in PXI-6552

[Themis70]

I am trying to loop a marker routed through PFI output to the strobe input. When I configure sample clock for the acquisition session to be "OnBoardClock", in the generation session PFI outputs the marker. When I change sample clock source to be "STROBE" for the acquisition session, PFI does not output. Is the generation timing module dependant from the acquisition timing module?

[Marco_Brauner]

Hi, can you post your code please, so I will have a look on it.

M. Brauner NIG

[Themis70]

Hi,

Thanks for your reply. See attached code.

Note that there is a physical connection (jumper on my fixture) between PFI1 and STROBE. Actually there are 50 ohms resistors from PFI1, PFI2, PFI3, Strobe, Clock Out to a common point with a weak pull down (4K7) to GND. My goal is to verify functioning of hardware (PXI-6552) and wiring continuity on the interconnection subsystem of the tester. Trying different combinations of driving-capturing pairs, I expect to extract failing pins or connections. Since now the only combination I cannot handle is the one I described.

Thank you in advance.

[Themis70]

In hsdio.chm file I found the above paragraph:

"Since NI digital waveform generator/analyzers only have one onboard clock, normally generation and acquisition sessions on the same NI device must use the same Sample clock rate. However, by choosing STROBE as the clock for acquisition operations, generation and acquisition operations can use two different timebases."

Additionally, in the same file, there is a block diagram describing clocking module. In that diagram it seems that there is the capability of routing strobe to the acquisition timing and control module and in the same time routing the on board clock to the generating timing and control module.

[Marco_Brauner]

Hi, I will test your code on a PXI-6552 as soon as I can. I´ll keep you in the loop.

M. Brauner NIG