Auto switch to BNC ref-in to replace backplane 10MHz if detected clock signal there with PXI-6608 on Slot2

[engwei]

Hi,

I m using chassis PXI-1045. The priority of backplane frequency is Slot 2 => Ref-In => Origin Backplane 10MHz.

But I wanted the backplane frequency to be in the priority order of Ref-In => Slot 2 => Origin Backplane 10MHz.

So, 

It is possible to change the priority ? maybe by edit the config file somewhere else ?

If the priority is uneditable, is there any function/VI to disable the Slot 2 PXI-6608 from replace the backplane 10MHz ? (from LabVIEW interface) Let say disable the device without access to MAX ?

Thanks a loottt 🙂

BR,

engwei

[lhaoxian]

Hi Eng Wei,

I've checked with R&D, and the priority of the clock selection is embedded in the firmware on the backplane. So unfortunately it is not possible to change the priority via software.

As far as the DAQmx functions are concerned, I did a check but was also not able to find any function that can disable the NI 6608 clock from being used to override the PXI backplane clock.

Is it a must that the NI 6608 be placed in slot 2, if it is not used to drive the backplane?

Best regards,

Victor

NI ASEAN

[engwei]

Hi Victor,

The PXI-6608 must be able to overide the backplane, so locate it at slot 2 is a must for my case. Thanks and hope to hear from you soon.

[engwei]

So any idea to switch the frequency between "ref in" and "PXI-6608 override clock" without taking out the PXI-6608 Slot 2 physically ?

Message Edited by engwei on 08-17-2009 02:57 AM

[lhaoxian]

Hello Eng Wei,

The priority of the clock selection between "Ref In" and the PXI-6608 override clock is embedded in the backplane firmware, and currently is unable to be changed in software at the moment. Also, there are no DAQmx functions to "disable" the PXI-6608 override clock. A more flexible option would be to make use of the PXI-6652 timing and sync module, which allows the user to determine which 10MHz clock source to use: onboard OCXO or routing via CLK_IN (this can act as the "ref in").

Best regards,

Victor

[engwei]

Hi,

Thanks for your re-reply again. Btw, is that possible to disable the card by LabVIEW code,

while the card is actually inserted to PXI slot (not only the override function)?