Справочник Пользователя для National Instruments NI PXI-1056

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Chapter 1
Getting Started
1-8
ni.com
Trigger Bus
All slots on each PXI bus segment share eight PXI trigger lines. You can 
use these 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 located in slot 2 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.
The PXI trigger lines from adjacent PXI trigger bus segments can be routed 
in either direction across the PXI bridges through buffers. This allows you 
to send trigger signals to, and receive trigger signals from, every slot in the 
chassis. Static trigger routing (user-specified line and directional 
assignments) can be configured through Measurement & Automation 
Explorer (MAX). Dynamic routing of triggers (automatic line assignments) 
is supported through certain National Instruments drivers like NI-DAQmx.
Note
Although any trigger line may be routed in either direction, it cannot be routed in 
more than one direction at a time.
System Reference Clock
The PXI-1056 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 250 ps 
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. Refer to Table B-4, 
. Sourcing an external clock on this pin automatically overrides 
the backplane’s 10 MHz source.