Hi, I want to design a precision stopwatch GUI from external clock.( Not using the computer internal clock).
Can NI 9401 use as an external clock source?
It all depends on the accuracy of the stopwatch you want to make. The I/O delay time for the 9401 is specified for 100ns.
If you are looking for a faster I/O delay time you should consider an R Series module with the CompactRIO chassis programmed with LabVIEW FPGA.
Here are some NI 9401 specs`
What you call stopwatch is called a counter or time intervall analyser, depending on you needs.
First questions would be target range and accuracy you need.
This would point to the timebase you need. (resolution and precision)
And finally lead to possible hardware .. including what kind of input signals you want to look at 😉