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Message access slower after VXI driver update



Actually we have this configuration : PCI-MXI2 linked to a VXI slot0 in a rack containing around 10 signal and measure boards of every type.

Computer is an old one under windows XP SP2, with NI-VXI 3.5 and i don't remember VISA  version which is from the same date as NI-VXI.

All programs are developed with CVI 8.

We are using mainly message based communication for board command but we use register based communication for data retrieving.


Last week, we did something we should never do. We updated the VXI driver which was version 3.5 to an earlier one (I don't remember the new version).

After this PCI-MXI2 driver was re-installed and all communication with VXI as significantly slowed down. We lost 15% of cycle time on each of the test sequences.

I can confirm that message based communication has slowed down, but I cannot confirm if register based communication has slowed donw too.


We swaped PCI-MXI2 board from a PCI slot to another, no change.


After this, we took a ghost we had from one year before. But, as the PCI-MXI2 board was not in its original position, the driver of the board has been re-installed. And in this case, we lost again our cycle time.


Then we try many configuration and parameters change without success. As we have a second identical test bench, we compared every parameters, and even we took parameters from second bench and we installled them in the first bench (using the .cfg files for PCI-MXI2 and VXIslot0).


Eventualy, we put the PCI-MXI2 board in its original PCI slot and use another ghost. As the MXI2 driver did not re-install, we did not loose cycle time this time! We just have to retreive the modifcation we lost since the ghost has been created.



So actually, I consider the system to be fragile, because if anything force a MXI2 driver re-installation, we will loose our actual cycle time! And we don't know why and how to correct it unless using a ghost.


If someone has an idea, I still have the hard drive with "corrupted" configuration to test it.


Thanks by advance!


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Can you tell me more about the driver you have installed ?

What version of VISA do you use with your card ?

To determinate the version of NI VXI which has been installed in your computer, you can open a files "Readme.txt" which is in this directory :

C:\Users\Public\Documents\National Instruments\NI-VISA\Examples\DotNET4.0\VxiInterruptHandler\cs


Moreover, the last version of NI VXI (NI VXI 5.3) do not support Windows XP SP 2 :



If you have installed this version of the drivers, I suggest you to download an an older version of the drivers like NI VXI like NI VXI 3.8 :



Best regards

Guillaume D
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Thank you for your reply, Guillaume.


I will check for the VISA version.


I can just tell by memory that fisrt VXI version was first 3.5, and was working as expected during the last 5 years. And (even with this version) as the PCI-MXI2 driver has been reinstalled it was no more working correctly.

Then we try to update to VXI 3.8 and VISA (??) => no effect

Then we update windows to SP3. and were able to update VXI to 3.9 only (no VISA upgrade, unless the one from VXI update).

But with no effect too.


The only way we found is to go back with a ghost of the HD and pray that there is no PCI-MXI2 driver re-installation (which did not happen during the last 5 years)..

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