Sample 20 times per second continually

[downerdce]

I'm trying to use grab samples off of every pulse from a digital input on another card. I have a digital input square wave that can trigger every acquisition for the analog cards. This happens 20 times per second, continually.

Is this possible to achieve? How do I do it at this rate?

I used the "Voltage - Finite Input.vi" example and set it up for Digital Edge and this grabbed my sample, but when I put it in a loop, the loop takes 600 ms to execute.

[JensG69]

What kind of hardware are you using?

Quite a bit of DAQmx NI hardware should be able to achieve this by defining an external signal for the ADC (instead of the usually used internal clock).

Regards, Jens

[downerdce]

Thanks for the reply Jens,

I have a cDAQ 9189 with a 9775 Analog card and a 9401 for digital triggering. I also have a 9361 counter card.

[downerdce]

Fastest I can get is 188ms... sample rate is high to push the 9775 into "Record Mode". Used "commit". Am I taking the wrong approach here?