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Chapter 2 Installation and Configuration
© National Instruments Corporation 2-7 VXI-8340 Series User Manual
Using the Request Offline/Go Online Feature
The VXI-8340 series controllers use the National Instruments MXI-3
interface for a high-speed, software-transparent PCI link between a host
controller and a VXI chassis. Because of the software-transparent nature of
the MXI-3 connection, be careful when power-cycling the VXI chassis
independently of the host controller.
To power-cycle a VXI chassis without rebooting the host computer, you
must explicitly tell the NI-VXI software to take the VXI-8340 series system
offline. When you take the VXI system offline, the NI-VXI driver saves
important configuration information about the state of the VXI-8340 series,
so that this state can be re-established when you restore power to the VXI
chassis. Placing the system offline also prevents the NI-VXI driver from
trying to communicate with the VXI-8340 series while the MXI-3 link is
down. While offline, the VXI-8340 series is inaccessible to applications.
The ONLINE front-panel LED turns off when the VXI-8340 series is
offline.
Note It is safe to remove power from a VXI chassis only after the VXI-8340 series is
offline. Failure to take the controller offline before cycling power can lock up the system.
There are two ways to place a VXI-8340 series controller in the offline
state. First, the VXI-8340 series includes a Request Offline button on the
front panel. This button is useful if the VXI chassis is separated from the
host controller by a great distance. Second, a
Request Offline option is
available in MAX by right-clicking on the VXI System icon under the
Devices and Interfaces view.
To bring a VXI-8340 series controller back online, use the Go Online
option in MAX by right-clicking on the VXI system icon under the Devices
and Interfaces view. Choosing Go Online tells the NI-VXI software to
restore the state of the VXI-8340 series to its pre-offline values.
The ONLINE front panel LED turns on when the VXI-8340 series is
online. At this point, it is safe to access the VXI interface.
Note You cannot leave a VXI system offline across a system boot. You can bring a VXI
system online only if that system was present when the host computer was last rebooted.