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PXI slot detection incorrect

I am using Windows 2000 on a Dell Pentium 4 with an MXI-3 connection to a PXI-1006 chassis. I have downloaded and installed the latest MXI-3 driver and installed the pxisys.ini for the PXI-1006 chassis in the WINNT directory. The I/O cards all seem to function correctly. Of the 14 installed cards, 9 cards report slot 0, and 4 cards report incorrectly as slots 13,14,15,17 and 18. What should I try next?
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Message 1 of 3

I would suspect a problem with your PXISYS.INI file. Did you generate this file with the MXI-3 software on your computer (procedure below), or did you copy this PXISYS.INI file from another location? If it is from another location, then you should instead re-generate it with the procedure below (this is copied from the "readme.txt" file included with the MXI-3 software).

To configure a MXI-3 system with a pxisys.ini file:
1) Ensure that the MXI-3 software is properly installed. See "Software Installation Instructions" for more information.
2) Run the MXI-3 Optimization Application (Start>>Programs>>National Instruments MXI-3>>MXI-3 Optimization).
3) Determine the model number of your PXI chassis (i.e. PXI-1000, PXI-1002, PXI-1006, PXI-1010, etc.).
4) Using the chassis model number, locate the corresponding pxisys.ini file. An .ini file for several PXI chassis can be found in the "\National Instruments\MXI3\pxisys" directory. The files are of the form pxisys_nnnn.ini, where nnnn is the PXI chassis model code.
5) Copy the pxisys_nnnn.ini file for your chassis to the directory (for example, c:\winnt or c:\windows).
6) Rename the copied file (in the directory) to "pxisys.ini".

If your MXI-3 software does not generate the PXISYS.INI files described in step #4 above, then you probably just have an older version of the software. The latest version can be downloaded from the link below if necessary:


Here is some background on why this is necessary with MXI-3. The PXISYS.INI file enables slot detection by listing a PCIBusNumber and PCIDeviceNumber for each slot of the PXI chassis. However, these numbers are not arbitrary, but instead are a function of the architecture of the PCI bus of your system. Specifically, they are a function of how many PCI-to-PCI bridges are built into your PC (typically 1 or 2), the MXI-3 link (which adds one bridge), and the construction of the chassis. Well, the piece of this puzzle that NI cannot possible know ahead of time is the number of PCI-to-PCI bridges built into your PC, which is part of what determines the PCIBusNumber. Therefore, the MXI-3 software must be run on the specific PC to detect the number of bridges, then create the appropriate PXISYS.INI file accordingly.

For more information, the KnowledgeBase "Slot Detection of PXI Modules" can be found at the following link:


Greg Caesar
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Message 2 of 3
Thanks, Greg, for your quick response. I did previously follow those instructions. I am, however, just now successful by first removing the devices from the MAX devices configurations, and then power cycling the PXI and PC BEFORE using F5-rescan in MAX.

It would seem that my confusion was because: if MAX has the wrong idea of the PXI slot numbers AND the devices are removed and F5 - rescanned without an intervening reinstall of the drivers then MAX persists with the wrong PXI slot numbers; despite the pxisys.ini file being correct from the latest reboot.

I clued in on this by manually changing the pxisys.ini file and noticing that the changes had no effect.

Roy Kinsella
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