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National Instruments Corporation
D-1
D
Power Sequencing
Requirements
The VXI-8340 series uses MXI-3 technology to extend the PCI bus of a
host computer to a VXI chassis transparently, so your host computer can
function as an embedded CPU module. Because of this transparent PCI
extension, it is important to maintain a strict power-on sequence when
turning on VXI chassis in a VXI-8340 system.
For the system software to discover and configure a VXI-8340 series
controller, power on all VXI-8340 chassis in the system before enabling
power on the host computer. If any chassis is not present when the host
computer initiates its boot process, the host computer may not configure
that VXI controller. If a VXI system is absent when the system boots, the
host must be rebooted to discover the missing VXI system.
Note
You must power on the VXI-8340 series at least 8 seconds before your PC.
When daisy-chaining VXI-8340 series controllers, power on VXI chassis
in reverse order, starting with the chassis furthest from the host computer.
For example, if Chassis A is connected to the host computer, and Chassis B
is daisy-chained to Chassis A, power on Chassis B before Chassis A, and
power on Chassis A before the host computer.
These power sequencing requirements also apply to the Request
Offline/Go Online feature (see the
Using the Request Offline/Go Online
section in Chapter 2,
Installation and Configuration
). If multiple
chassis in a daisy chain are offline, power on these chassis and bring them
back online starting with the chassis furthest from the host computer. Using
the example above, if you take Chassis A offline, you must also take
Chassis B offline. When you bring these VXI systems back online, power
on Chassis B first, followed by Chassis A.