Switch Hardware and Software

[Phil E]

I have 4 SCXI-1127 cards plugged into an SCXI-100 chassis with a USB interface.

I am using VBA in Excel.

On our old XP PC, the niSwitch_init command would execute in 1-2 seconds per card.

On the new windows 7 PC, this command takes about 8-10 seconds per card. Or, about 30-40 seconds for the 4 cards.

the exact commands I'm using are:

    status = niSwitch_init("SC1MOD1", VI_TRUE, VI_TRUE, card1)

    status = niSwitch_init("SC1MOD2", VI_TRUE, VI_TRUE, card2)

    status = niSwitch_init("SC1MOD3", VI_TRUE, VI_TRUE, card3)

    status = niSwitch_init("SC1MOD4", VI_TRUE, VI_TRUE, card4)

Has anything changed in the Windows 7 version of niSwitch?

What could be causing it?

Subsequent commands to the switch execute in the same time as before. It's onlt the niSwitch_init command that's slow.

Thank you,

[Ali M]

Hello Phil,

Several factors can affect the run-time performance of your application; however, there's a similar issue addressed in the following KnowledgeBase, where NI-Switch applications have shown to run slower on Windows 7 machines. If this is the case, National Instruments recommends either upgrading to NI-Switch 4.2 or enabling the HPET on your Windows 7 system.

Best regards,

Ali M

Applications Engineer

National Instruments

www.ni.com/support

[Phil E]

Hello Ali,

This appears to address my issue. But, it says the solution is to upgrade to niSwitch 4.2.

I can only find niSwitch 4.1 here: http://joule.ni.com/nidu/cds/view/p/id/2225/lang/en

Where can I get the 4.2 update?

Thank you,

[Ali M · Accepted solution]

Hello Phil,

Thank you for your response. The KB indicates NI-Switch 4.2 (and later) because the problem will be fixed with the release of these drivers. However, the official release date of NI-Switch 4.2 has not been announced yet. At this juncture, the best work around workaround would be to enable the HPET on your Windows 7 system.

Best regards,

Ali M

Applications Engineer

National Instruments

www.ni.com/support

[Now_With_Under…]

Hello Phil,

The increased time is due to a low level change in Windows 7.  If the wait time is not tolerable and you are not able to enable HPET, I recommend using Windows XP for now.