DI edge triggered

[VladimirZav]

Hello,

I have  a small question.

I use board PCIe-6323 and need to acquire finite number of samples with defined sampling rate on port0.pin29  (it is not PFI), but I need to start from first falling edge on this pin.

Is it possible?  And is there some example written in C?

Thank You for help

Vladimir

[ZYOng]

You can refer to C:\Users\Public\Documents\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Digital\Read Values\Read Dig Chan-Int Clk-Dig Ref

In line 62, use DAQmxCfgDigEdgeStartTrig and DAQmx_Val_Falling instead.

For more information, read NI-DAQmx C Reference Help in C:\Users\Public\Documents\National Instruments\NI-DAQ\Documentation

[Kevin_Price]

On most NI devices, DIO lines available for hardware-timed IO do not serve double duty as PFI terminals.  I would just parallel wire from 0.29 over to a PFI terminal that can act as a start trigger for your task.

Sorry, can't help with any C examples.

-Kevin P

[VladimirZav]

Thank You for your answers.

My problem is that all digital inputs (and also all analog) are already used by external hardware and I can not use external PFI input.

Vladimir

[Kevin_Price]

Then you'll probably need to run a continuous task, and do post-processing in software to find the trigger position and then retain only the desired finite # of samples.

-Kevin P