multiple lan labview real time

[LV_Pro]

Good Afternoon,
    I have a PXI box running LabVIEW RT 8.5. It has a non-NI CPU, which has two network adapters. I am able to see the machine in MAX using either adapter, as long as the one I'm using is declared the primary one. What I need is the ability for my program to be able to choose the network adapter that it is using. In MAX, when I use the "Advanced Ethernet Settings" button it shows me both network MAC addresses, and lets me set up an IP address on the second one, but so far I've been unsuccessful in running my program, while hooked up to the primary adapter (to allow viewing the program on my desktop) and then connecting to it through the alternate port. I've tried using the "Simple Data Server.vi and Simple Data Client.vi" examples, having modified the Server example to feed in the other adapter's net address, to specify it as the one to listen on, but no joy. If I run it with the "primary address" start it, swap cables with my laptop running the client example aimed at the "primary" ip address, works like a champ. If I set it up to talk on the other, non-primary, connection, my laptop returns a :
"Error 59 occurred at an unidentified location

Possible reason(s):

LabVIEW:  The network is down, unreachable, or has been reset."

message.  Not seeing what I'm doing wrong or how to proceed from here.

Thanks,

[Jason_Whaylen]

Hi LV_Pro,

Thank you for contacting National Instruments.  From the information you have provided here, it sounds like you are on the right track with getting your application up and running.  However, I am still a bit unclear on a couple of different aspects you are discussing here.  It looks like you have had success when using only the primary adapter.  Are the problems only when trying to use the alternate port?  Are you essentially looking for a method to programmatically change which network adapter to use?  I'm not sure if this can be achieved, but searching through some past forum threads seemed to provide the best suggestions.

From my understanding, in order to use the network adapter to connect to a Real-Time target, it must be configured as the primary.  However, this KnowledgeBase article might be helpful in this situation.  I think the important information to take notice of is the location of the RT target as far as subnet.

I hope this helps.  Let me know if there is something I can clarify, or if you have more questions and information to consider.  Have a great day!

Jason W.

 

Message Edited by Jason W. on 11-13-2007 07:27 PM

[LV_Pro]

Well, it appears that it all revolves around the subnet addressing. As I seemed to have forgotten, but looking back a a posting from Dennis from quite awhile ago, the OS will not talk through a secondary NIC unless it is on a different subnet. Now I can have either port establish communications (though not at the same time apparently), which is what I wanted. I wasn't trying to actually connect with the real-time system, as when developing on the desktop and then deploying to the RT, rather wanted to have my program able to, while running, make a connection on either port, allowing a fail over scheme to allow connecting on the other path if the first fails.




Message Edited by LV_Pro on 11-13-2007 10:11 PM