If you need timing precision of 1ms I would recommend using a real-time system. The CVI Real-Time Module can provide microsecond precision. In Windows, even with a sleep none policy, your application will still yield to other processes and is thus unreliable for 1ms precision. Additionally, the resolution of the timer is 1ms, but this does not necessarily mean that it is accurate to 1ms. The timer function must retrieve the time from the system clock and then return it to you application. There are several lines of code that are ran in between when it polls the system for the time and when it returns the information to the calling function. Windows could also have switched processes during that time. The inaccuracy is also very dependent on the system. This is why I would not recommend relying on timing functions for accuracy less than 10ms on a Windows system. However, the time should be very accurate on a real-time system.
National Instruments
