Is is possible to open VISA session to PXI backplane.

[Bob Rafuse]

I have a Windows 2000 box with a MXI-3 controller connected to a single
PXI-1000B chassis using NI-MAX 2.2. I am familiar with VXI but new to PXI.

Is there a way to open a VISA session to the PXI backplane, as was possible
with VXI?

I tried:

i32Status = viOpen
(
p_hResMan,
"PXI0:0:BACKPLANE",
VI_NULL,
VI_NULL,
&p_hPxiBackplane
);

But it generates the error:

"Insufficient location information or the requested device or resource is
not present in the system."

Is there some special configuration I need to do in order to access the PXI
backplane in this manner. Is this even possible? If not, then how do I
perform backplane operations in a PXI chassis (such as trigger manipulatio
n,
etc)?

Thanks,

Bob Rafuse
Etec, Inc.

[Claudia]

Bob,

Unlike VXI backplanes, you cannot open a session to a PXI backplane.

PXI is built on the CompactPCI platform, and PXI adds more features to this platform. So a PXI chassis actually uses a PCI bus. The interrupts are handled by the drivers of the boards, like any other PCI board.

If you need to send a trigger signal between PXI boards, you could use any of the 8 PXI Trigger Lines in the backplane. All you need to do is make sure that the PXI boards have physical connections to those lines (that information should be in the User Manual of the board). Almost all NI boards can receive and send signals using PXI Trigger Lines 0,1,2,3,4,5,and 7.

There is more detailed information on the PXI mechanical and electrical fetures in the first chapters of the PX
I specification at http://www.pxisa.org

Hope this helps,

Claudia Lorente
Applications Engineer
National Instruments

[Bob Rafuse]

Claudia,

Thank you for the reply.

> If you need to send a trigger signal between PXI boards, you could use
> any of the 8 PXI Trigger Lines in the backplane. All you need to do is
> make sure that the PXI boards have physical connections to those lines
> (that information should be in the User Manual of the board). Almost
> all NI boards can receive and send signals using PXI Trigger Lines
> 0,1,2,3,4,5,and 7.

Just so I'm clear on what you're saying, what I'm hearing is:

The MXI-3/PXI controller can not drive the PXI trigger lines. There is no
way to source a PXI backplane trigger from software. All trigger lines must
be driven by hardware.

Is the above true?

Thanks,

---
Bob

[Claudia]

Bob,

That's right. The MXI-3 extender is just a PCI to PCI bridge. It cannot drive the PXI Trigger Lines.

You can program an application that will have a PXI board generate a trigger signal when certain event occurs. Then you can route that signal to one of the PXI Trigger Lines and have other boards read the signal and resopnd to it.

The PXI Trigger Lines are very useful when you need to send a signal from one PXI board to another one(s). They are very useful for triggering applications. However, they are also used to send analog signals between boards without external cabling.

Please keep in mind that the capability of a PXI board to access the PXI backplane features depends on the board itself. The PXI backplane will have all its fea
tures available (8 PXI Trigger Lines, 10 MHz Backplane clock, Local bus Right and Left, PXI Star Trigger), but is up to the designer of the PXI board to make the physical connections to the PXI backplane. The User Manual of every board shoudl tell you what the board is capable of doing.

Regards,

Claudia Lorente
Applications Engineer
National Instruments