I have met a problem related with 1 MHZ timed loop. i am using a PXI 8186 as a controller, LabVIEW RT 7.1 as software platform. when I chose 1MHZ clock, i found that it is not accurate at all. i had hoped that the timed loop execute the diagram in every 500,000us. I use the function "tick count" to see the actual time interval, sometimes i got 900,000us, sometimes I got 100,00us. could someone tell where would the problem possibly be?