Mux problem: No legacy device supports the specified topology.

[Les Bartel]

I just set up a new laptop computer to run my application and now I get the described error.  The PXI 2527 mux scrolls through my signals, delivering them to my PXI 4071 DMM.  I can use the soft panels to select a channel on the mux and the dmm will read the expected voltage.  niSwitch Initialize with Topology fails with the given error (-1074118644).  What am I missing?

[lrallen]

Les,

Check out the links below and see if they resolve your issue.  Let us know how it goes. 

http://digital.ni.com/public.nsf/websearch/8130049893D6461E86256F3B00461E1B?OpenDocument

http://digital.ni.com/public.nsf/websearch/22CF7E6B27B6995B86256DDB0058F39B?OpenDocument

Regards,

Lon

[Les Bartel]

I wonder if it has something to do with the configuration of my 1045 chassis.  I deleted the config and reconfigured, but had the same results.  When I attached my old notebook computer to the chassis, everything works fine.  Reattaching the new notebook gives the same problem.  I do notice that the descriptor? for the switch card is different.  Old notebook has PXI7::11:instr and the new notebook has PXI15::11:INSTR.  I renamed the card to "Mux" on both notebooks and address it as "Mux" for the resource name on the VI input.

[lrallen]

This could be the case.  Have you assigned the controller and chassis in MAX?  If not this can be done by right clicking on the controller and chassis and assigning the appropriate controller or chassis. 

[Les Bartel]

I've assigned the chassis (PXI 1045).  As I said, I can talk to the problem switch (2527) and other cards on the bus through the soft panels.  I can also control GPIB instruments with my own VIs.  I can hear relays engage when I attempt to run my problem VI.  I'm guessing that those relays are on the 2565 relay cards.  My application fails during initialization.  I copied the pxisys.ini file from the old laptop to my new laptop and rebooted.  There doesn't appear to be any difference in behavior.  The pxisys.ini files were different (but both were for the 1045 chassis).

[Bushman Warrior]

Dear Les

I had a similar problem a while back when switching to a new chassis and PC. In my case the problem occurred when I installed newer NI-Daq drivers on the new machine.

The problem was solved by switching to using DAQmx to control my switchcard (PXI 2564). Maybe you could consider this?

Hope this helps

Regards

Mark

[Les Bartel]

After a good bit of troubleshooting, the eventual solution was to do the following:

Move mux to different slot

Reboot and configure

(it now works)

Move mux back to original slot (so it is on the same bus as the DMM)

Reboot and configure

It still works.

Go figure...