National Instruments PXI PXITM -1000 - Manual (Page 17)

Chapter 1 Getting Started
© National Instruments Corporation 1-7 PXI-1000 User Manual
operations performed on other modules in the system. Modules can pass
triggers to one another, allowing precisely timed responses to
asynchronous external events the system is monitoring or controlling.
System Reference Clock
The PXI-1000 supplies the PXI 10 MHz system clock signal (PXI_CLK10)
independently to each peripheral slot. An independent buffer (having a
source impedance matched to the backplane and a skew of less than 1 ns
between slots) drives the clock signal to each peripheral slot. You can use
this common reference clock signal to synchronize multiple modules in a
measurement or control system. You can drive PXI_CLK10 from an
external source through the PXI_CLK10_IN pin on the P2 connector of the
Star Trigger Slot. (See Table B-1,
P1 (J1) Connector Pinout for the System
Controller Slot , in Appendix B, Pinouts .) Sourcing an external clock on
this pin automatically disables the backplane’s 10 MHz source.