Hi Ashesh,
Thank you for contacting National Instrument's support! That's an interesting question, and I think that you're very close to the solution already. It sounds like you already have the foundation to your program, which will probably be very similar to our shipping example called "Gen Dig Pulse Train-Finite-Retriggerable."
Basically, our counters are only hardware triggered. If you look at the source list for all potential trigger sources, you'll notice that they are all hardware related. Unfortunately, we don't have any software triggers as such.
However, what you could do is use a software trigger to generate a digital high on one of your digital ports, and wire that over externally or internally (depending on your hardware, using the Connect Routes vi. Check in your Measurement and Automation Explorer >> DAQmx Devices >> Device Routes to see what available options you have). You would want to do something similar to the "Write Dig Chan" example program that is also shipped with LabVIEW.
I hope that this points you in the right direction. If you have any questions on implementing this solution, feel free to ask again and I'd be more than happy to help. Thanks for choosing National Instruments!
Regards,
Daniel L.
Applications Engineer
National Instruments
