Chapter 3
Hardware Overview
©
National Instruments Corporation
3-15
NI PXI-6682 User Manual
The PXI star trigger outputs may be synchronized to CLK10 except when
routing future time events. Refer to the
Choosing the Type of Routing
section for more information about the synchronization clock.
Choosing the Type of Routing
The NI PXI-6682 routes signals in one of two ways: asynchronously or
synchronously. The following sections describe the two routing types and
the considerations for choosing each type.
Asynchronous Routing
Asynchronous routing is the most straightforward method of routing
signals. Any asynchronous route can be defined in terms of two signal
locations: a source and a destination. A digital pulse or train comes in on
the source and is propagated to the destination. When the source signal
goes from low to high, this rising edge is transferred to the destination after
a propagation delay through the module. Figure 3-5 illustrates an
asynchronous routing operation.
Figure 3-5.
Asynchronous Routing Operation
Some delay is always associated with an asynchronous route, and this
delay varies among NI PXI-6682 modules, depending on variations in
temperature and chassis voltage. Typical delay times in the NI PXI-6682
for asynchronous routes between various sources and destinations are given
in Appendix A,
Specifications
.
Asynchronous routing works well if the total system delays are not too long
for the application. Propagation delay could be caused by the following
reasons:
•
Output delay on the source
•
Propagation delay of the signal across the backplane(s) and cable(s)
•
Propagation delay of the signal through the NI PXI-6682
Trigger Input
Trigger Output
Propagation Delay
t
pd
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com