real-time clock frequency in PXI systems?

[jonpo]

I'm using a PXI system to sample randomly triggered data. The application is written in Borlands DELPHI, using the NIDAQ driver library. I time stamp each event by reading the Windows clock ("GetTickCount" declared in the kernel32 module). In a normal Windows system, the clock does not "tick" very frequently, but I have a vague recollection of having read that the PXI clock ticks faster, thus giving better precision. What is the PXI system clock frequency used and reported by Windows?

[Doug_Kunz]

Jonpo,

Thanks for using the National Instruments discussion forum. Your recollection of the PXI clock may have been related to the 10 MHz backplane clock rather than the system time. Do you remember the specific place you read about this? NI PXI controllers are built out of laptop components and use the same chipset as a �normal Windows system.� So the system clock on an NI PXI controller will give you the same precision as computer.

There are a few different functions in addition to GetTickCount that you can use to get the current time. Among them are GetSystemTime. You can refer to Microsoft�s webpage for more information on this topic. Following is a link to Microsoft�s main Time page.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/
sysinfo/base/system_time.asp

I hope this helps!

Doug K.
Application Engineering
National Instruments