Chapter 1
Getting Started
1-8
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National Instruments Corporation
Trigger Bus
The eight PXI trigger lines are bused to each slot. You can use the trigger
lines in a variety of ways. For example, you can use triggers to synchronize
the operation of several different PXI peripheral modules. In other
applications, one module can control carefully timed sequences of
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-1000B 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,
Pinout for the System Controller Slot
, in Appendix B,
.) Sourcing
an external clock on this pin automatically disables the backplane’s
10 MHz source.
