DAQmx programming single channel multiple trigger analog input

[Sean_C.]

Hi Ralph,

That is a good point. You can set up a retriggerable pulse train using your external clock as a timebase. However, the highest frequency you will be able to get with this method is one half of your external clock's frequency. If you set the "highTicks" and "lowTicks" parameters both to 1, your resulting train will go high until it receives a rising edge from your timebase. Then it will go low until the next rising edge of your timebase.
See the attachment for a visual representation of this...

Sincerely,

Sean C.
Applications Engineer
National Instruments

[ralphlevy]

Thanks Sean for identifying the timing issue (1/2 external clock).

Can I run the external clock at 2.4 MHz to get a 1.2 MHz conversion rate? Will the M-series board (NI PCI 6259) run that high? The A-to-D will run up to 1.25 MHz, but can the counter take an external clock at 2.4 MHz?

Ralph Levy

[Sean_C.]

The counters on the M Series can take an external base clock of up to 20 MHz, so this should be no problem.

Sean C.

[ralphlevy]

Sean,

Thank you for your help and your persistence.

As soon as I get a wiring problem fixed, I will try this out.

Ralph Levy
CTO
Quant Engineering