Max triggering frequency in PXI 6552 card

[morsick]

Hello,

does anyone know, what is the maximum frequency of trigger signal for acquiring data in pxi 6552 card? I use the card for acquiring small packets of samples (max 32). Each packet is read after trigger pulse, which I want to generate at rate 20k / s. But maximum frequency of triggering is about 2 kHz, after this some packets are lost. I modified 'HSDIO Acquisition' signal express function by adding 'configure trigger' and moving 'read waveform' outside, so that only reading is repeated within 'while loop', while initialization of device is executed only once. This speeded up my application about 20 times, but that's end of my ideas. Does anyone have a similar problem and can advise me anything?

Thanks in advance

[Stefo]

Hello Morsick,

If I understand correctly, you need to acquire small packet (fix length of samples) each time you receive trigger - something like retriggerable, finite acquisition. If this is correct, then I believe you could use Dynamic Multi Record Acquisition. What you need to do is to configure Start trigger as well as Advanced trigger - you can follow instructions from HSDIO Retriggerable Multi-Record Acquisition.

There should be available example which should help you - NI-HSDIO Retriggerable Multi-record Acquisition.

I believe that you should be able to go way above 20kHz with triggering. If you see specification, it sais that you need 143S in maximum to rearm Advanced trigger (the one which restarts acquisition).

Can you verify if multi-record acquisition can satisfy your needs?

Kind regards,

Martin Stefik

NI Application Engineer

[e-williams8@ti.com]

I have a simular need, I need to measure DIN Setup & Hold time in Master Mode (This is where the Device Under Test generates WCLK & BCLK), which means I need to trigger off of each WCLK rising edge or falling edge while moving DIN with respect to BCLK rising or falling edge.  And I need to do this at WCLK speed (48KHz).