VISA TCPIP server

[AndyN]

Is it possible to make a TCPIP server using VISA drivers?

I can do it with the TCPIP primitives but labvie RT does not allow changing the Nagle delay to OFF.  On the other side I do not see a way to use VISA as a server. I do not see any option for a listener.

This all on a RT PC and a regular NIC but compatible with RT.

Or the right question is : how to make a TCPIP server on RT with the Nagle delay set to OFF?

[Christian Mergl]

Hey,

The following KB contains a .llb which again contains a Vi called "TCP_NoDelay.vi", I think this is what you are looking for.

http://digital.ni.com/public.nsf/allkb/7EFCA5D83B59DFDC86256D60007F5839?OpenDocument

Christian

[AndyN]

I mentioned before that the TCPIP primitives dont work with RT and Nagle OFF.

It does not work under RT.

[Christian Mergl]

Hey,

sorry about that. It is almost impossible to read over the RT but I managed it somehow.

I don't have an answer right now in terms of the nagle algorithm on RT but there might be another option for you, depending on the purpose to disable the nagle algorithm?

Christian

[AndyN]

No reason to be sorry. I need nagle off on RT to feed my control loop with some data. Very few people do real time control using TCPIP - NAgle delay off is a must.

[Christian Mergl]

Hey,

You could use Realtime Shared Variables (Tools>Realtime>Configure Time-triggered Network) or build up your own protocol using UDP.

http://zone.ni.com/devzone/cda/tut/p/id/4720 (Using Time-Triggered Networks to Communicate Deterministically Over Ethernet with the LabVIEW 8 Real-Time Module)

Christian

[AndyN]

Thanks for the idea. I need to read  about to find out if it is right. I like TCPIP cause it is good across different OSs. I must say that I did not have some much trouble with it using C  and Linux RT at all.