LabVIEW program interfers with system clock on PC

[Roese]

I am using an SCXI system to do some basic data acquition.  However, when I run the program, the PC's system clock slows down.  How can I fix this problem?  When I disable the Analog Input portion of the program, the system clock time returns to normal.

[Elijah_K]

Roese,

I have some quick questions for you in order to get a better idea of the error you're experiencing and the possible reasons behind it:
What module are you using to connect your PC to the SCXI?  What modules are you using to aquire your analog input?  What are you observing that indicates that the PC clock has slowed down?  In other words, how are you quantifying the speed of the system clock?  How have you configured your analog input task?

Any other information you think might be useful would be appreciated. 

[Roese]

The interface from the PC to the SCXI chassis is a PCI-MIO-16XE-10.  The SCXI chassis has six 1102 modules for analog input.  I am reading 42 Thermocouple channels.  As far as quantifying the inaccuracy in the sytem clock,  I just used a stop watch to time the clock display in the sytem tray.  It took 70 seconds for the sytem clock to display 60 seconds.

[Elijah_K]

Roese,

This phenomenon can occur when the system's processor is attempting to handle interrupts during a high speed data acquisition and actually misses internal service interrupts to update the clock.  If your computer supports bus mastering, you can use DMA mode and avoid sending a heavy load through the processor.

For more information and troubleshooting steps, check out this knowledge base article:
http://forums.ni.com/ni/board/message?board.id=250&message.id=25875

Good luck!