National Instruments VXI-1394 - Manual (Page 54)

© National Instruments Corporation D-1 VXI-1394 User Manual for Windows
D
Common Questions
This appendix addresses common questions you may have about using the
NI-VXI/NI-VISA software on the VXI-1394 platform.
What does hot plugging mean in terms of IEEE 1394?
The concept of hot plugging in 1394 means that you can remove and
insert 1394 cables without powering down your computer and devices. The
1394 Plug and Play architecture is designed so that the host computer can
recognize when to load and remove the appropriate drivers. However,
notice that inserting or removing any 1394 cable results in an interrupt
condition on all devices, which may adversely affect any applications using
the VXI-1394 at that time. For that reason, NI recommends closing all
1394-related applications before changing your 1394 bus configuration,
and running Resource Manager after adding any new 1394 devices to your
system.
Does it matter whether I plug in a 1394 device to the PCI-1394 in my
computer or to the VXI-1394 in my mainframe?
The only difference is the topology of the system. If your system consists
of a PC connected to a VXI-1394 which is in turn connected to a digital
camera, you can get the best performance by connecting a third peripheral
to the VXI-1394 rather than to the PC or the digital camera. This restricts
the maximum distance between any two nodes to two cable segments.
Connecting the third peripheral to either the PC or the digital camera would
create a maximum distance of three cable segments between any two nodes.
Use only a tree topology to build your system. A closed loop is illegal and
will not work. For example, if you have a PCI-1394 and a VXI-1394 cabled
together and you add direct connections from both of them to the same
digital camera, you create a closed loop. A 1394 device should have only
one connection to the 1394 system.
Can I have both a PCI-MXI-2 and a PCI-1394 interface in the same
computer?
Yes.