If you want to know the time, an easy way is to use the Profiler (Tools>Advanced>Profile VIs). There's also the shipping example called Timing Template (data dep) that you can drop you VI into and get a time result back.
As far as why it's taking 1 sec, you first need to determine where the time is being spent and the Profiler should help with that. You might be doing some setup of the daq board and the actual acquisition is taking some small amount. If that's the case, putting the acquisition in a loop should help. You might also have configured the acquisition such that it takes that amount of time. For example, if you set it for 1000 scans per second and return 1000 scans, each measurment will take 1 second. Thirdly, the board or driver might be slow
. The Profiler should also help here. Lastly, can you post your program? Seeing what youo're actually doing will help isolate the problem.
