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Chapter 2
Installation and Configuration
The PXI specification allows for many combinations of PXI chassis and system modules. To
assist system integrators, the manufacturers of PXI chassis and system modules must document
the capabilities of their products. PXI Express devices must provide a driver and
.ini
file for
identification. These files are provided as part of the PXI Platform Services software included
with your system controller. The minimum documentation requirements for PXI-1 are contained
in
.ini
files, which consist of ASCII text. System integrators, configuration utilities,
and device drivers can use these
.ini
files.
The capability documentation for a PXI-1 chassis is contained in a
chassis.ini
file provided
by the chassis manufacturer. The information in this file is combined with information about the
system controller to create a single PXI-1 system initialization file called
pxisys.ini
(PXI System Initialization). The NI system controller uses MAX to generate the
pxisys.ini
file from the
chassis.ini
file.
Device drivers and other utility software read the
pxiesys.ini
and
pxisys.ini
file to
obtain system information. For detailed information about initialization files, refer to the PXI
specification at
www.pxisa.org
.
Trigger Configuration in MAX
Each chassis has one or more trigger buses, each with eight lines numbered 0 through 7 that can
be reserved and routed statically or dynamically. Static reservation
pre-allocates
a trigger line
to prevent its configuration by a user program. Dynamic reservation/routing/deallocation is
on
the fly
within a user program based upon National Instruments APIs such as NI-DAQmx. Static
reservation of trigger lines can be implemented by the user in MAX through the
Triggers
tab.
Reserved trigger lines will not be used by PXI modules dynamically configured by programs
such as NI-DAQmx. This prevents the instruments from double-driving the trigger lines,
possibly damaging devices in the chassis. In the default configuration, trigger lines on each bus
are independent. For example, if trigger line 3 is asserted on trigger bus 0, by default it will not
be automatically asserted on any other trigger bus.
Complete the following steps to reserve these trigger lines in MAX.
1.
In the Configuration tree, click on the PXI chassis branch you want to configure.
2.
Then, in the right-hand pane, toward the bottom, click on the
Triggers
tab.
3.
Select which trigger lines you would like to statically reserve.
4.
Click the
Save
button.
PXI Trigger Bus Routing
Some National Instruments chassis, such as the NI PXIe-1085 Series and the NI PXI-1044/1045,
have the capability to route triggers from one bus to others within the same chassis using the
Trigger Routing
tab in MAX, as shown in Figure 2-10.
