Accessing MXI Connection Monitor Programmatically

[dlobies]

The MXI-4 (PXI-8336) User Manual states that you can "programmatically retrieve data about the link, chassis, and modules you have installed."  I have two PXI-1042 chassis bridged together using PXI-8336 cards, and I would like be able to detect if the link is broken between the chassis.  I see the device "MXI-4 Connection Monitor "PXI13::9::1::INSTR" in MAX, but the only attribute I can see is "Bridge Retransmit Count" (another useful piece of info for error checking).  There doesn't seem to be any utility in NI-VISA to access this information--am I missing something, or maybe this info is kept in registers?

Bottom line, I would like to generate an error in my LabVIEW code if the link is lost between the chassis.  Obviously, if this happens, I would get other errors related to the instruments in the downstream chassis, but it would be useful to be able to detect if the fiber optic cable was broken or disconnected.

Any suggestions would be greatly appreciated.

[Marcus_M]

Hi,

Could you please give me a little more information on the software that you have?  Which drivers are currently installed, which operating system do you have, and are these PXI chassis hooked up to a computer or do they have an embedded controller?  

Thank you.

Regards,

Marcus 

[dlobies]

Marcus,

I have a PXI-8108 real-time embedded controller in "Chassis 1" with a PXI-8336 MXI-4 pair extending the PCI bus to "Chassis 2".  LabVIEW Real-Time 10.0 and NI-VISA 5.0 are installed on the controller.  I am running a real-time executable and using a laptop to display the remote front panel in a browser.

Unfortunately, I discovered today that if I lose the link between the chassis, the controller disconnects and my application stops.  Presumably this is due to the PCI bus taking issue with losing half of its devices...

So monitoring the link is a moot point.  However, "Bridge Retransmit Count" might still be useful to keep tabs on the health of the bridge or the connection itself.  I just don't see any way programmatically to access this info, even though I see it in MAX.

Thanks

[Marcus_M]

Hello,

I'm having trouble locating the MXI-4 Connection Monitor on my chassis that has my controller and 8336 in it.  Would it be possible for you to send me a screen shot of the connection monitor from your chassis and point out to me where you found it?  

Thank you for your help.

Regards,

Marcus 

[dlobies]

Marcus,

Sorry, I can't get a screenshot (confidential network).

The connection monitor should be listed in MAX under Remote Systems/<Controller>/Devices and Interfaces/<Chassis>/<slot no.>: MXI-4 Connection Monitor "PXIxx::x::x::INSTR"

Bridge Retransmit Count is under Remote Systems/<Controller>/Devices and Interfaces/PXI System/<Chassis 1>/PXI Bridge (PXI-MXI-4).  You have to right-click "PXI System" and select "Show PXI bus details", then left-click the PXI Bridge.

[Marcus_M]

Hi,

Have you taken a look inside of the Visa Property Node?  It's located under Instrument I/O, VISA, VISA Advanced, and then VISA Property Node.  This property node has features such as Chassis Number, Slot Number, and Link Width.

Regards,

Marcus