UDP Normal and Multicast Not working on Linux RT based NI RT Systems

[MrJackHamilton]

yes, I see that I'm writing the IP in the Open Send function...when I have time, I'll take that out.

FTY: this is from those RT systems that have dual ethernet ports.

Jack

[MrJackHamilton]

So I tried it again, removing the IP address input on the UDP MCast open and still get an error 59 - Unreachable address. As I am connected to the sBRIO via ethernet, the enthernet is of course not down...

[MrJackHamilton]

To give a fair shake to the sbRIO-9636 I formatted it and reinstalled *ALL* the software...No joy.

[Spex]

With regards to 'still get an error 59'...  That is a new error message/number.  The previous error was generated on the receiver and was error 56. Error 59 is now happening on the sender and is a different condition.

[MrJackHamilton]

Spex,

To clarify: I changed the UDP MCast Sender by removing the IP address of the sending host (required for dual ethernet cRIO). This was posed by one of the responders to my post where I posted the diagram code.

I ran this on the sbRIO-9636 and still got nothing coming out - nothing received on Host PC. Then formatted the sbRIO, installed ALL the software - ran it again...got the same problem....nothing received.

Step 2:

In desperation: I tried the UDP MCast 'Receive' on the sbRIO and get error 54...so there is definetly a problem...

NOTE: Normal UDP works!. So I know it's not a firewall issue on my host PC.

I'd like to clear this problem up.

Regards

Jack Hamilton

[diabeticdaniel]

Jack,

I ran the example VI a second time and was able to see data transferred regardless of where the Sender and Receiver were (i.e, Sender on sbRIO/Receiver on host, Receiver on sbRIO/Sender on host). You keep mentioning the requirement for dual ethernet cRIO for the extra code you were using, but the sbRIO 9636 only has a single ethernet port. I feel like there is some confusion somewhere. Does the sbRIO you're using have multiple ethernet ports?

[nico1981-2]

Hello Jack,m

i have the same problem... error 59... is there a solution ?

BR nico

[MrJackHamilton]

BR,

No...there is not. It's how much of the TCP/IP Stack NI implemented on that particular device. And there is NO list that I can find from NI that states this before you open the box.

Further; getting any specific information about your sbRIO, cRIO, SOM begins a ping-pong game between the hardware Product Line Manager and the RT NI team...what really defines what's working your RT hardware is controlled by the RT software group. And they have not fully implemented things uniformily across the RT line.

Normal UDP works. But it's not a clean as Multicast.

BTY: You cannot open more that one UDP READ on the same Win system....

Regards

Jack Hamilton

[MrJackHamilton · Accepted solution]

I've found a solution to the problem of Multicast UDP on RT systems [at least sbRIO and likely cRIO]

Specifically: you need to wire the IP of particular ethernet port of the RT system into the UDP Create function. Otherwise, with multi-IP port RT systems the obtain cannot choose.

I've attached a working Multicast Sender you can drop into your RT code. Additionally, it includes the IP of RT system, Model, SN and Firmware version.

Enjoy,

Jack Hamilton