Comms Failure detection on GPIB-ENET 10/100

[JoeK]

Hi,
I'm using GPIB-ENET 10/100 units on my network to connect to test equipment via software written in C++ on Linux. I'm using the latest Linux driver on SuSE 8.0. Everything seems to be working fine.
However, for some high availability processing, we would like to be able to switch to an alternate GPIB-ENET controller if we lose the network on a particular GPIB-ENET device. Both devices are connected to the same GPIB bus.
When testing, I've found that I can do this when I first start my program - I get an EDVR error and switch to the other controller - no problem. However when I unplug the ethernet cable (or turn the unit off) after having been communicating with te device for a while, the "Send" command just hangs th
ere. If I plug the cable back in after a minute or two, it picks back up and completes the command. I'd like to get the same error so I can switch to the next controller, but I don't. This halts all my processing, since it blocks on that command.
Has anyone seen this behavior? Is there anything I can do to fix it?
Thanks in advance for any help!
- Joe Kralicky

[Ray K]

Hello Joe,
Try using VISA to communicate. I wrote an program that did constant communication and when I unplugged the device, I recieved an error after 3-4 minutes.
Ray K
NI Applications Engineer

[JoeK]

Hi Ray,
Thanks for your reply.
I don't think my program could sustain a 3-4 minute blockage like this. I may have to do some low level network stuff to make sure it's still alive before I talk to it.
Thanks!
Joe