Question regarding Network heartbeat

[Iniesta_Luján]

Hello

I'm really appreciated if anyone help me out whether Veristand has network heartbeat functionality on it.

[background]

I use Veristand for HIL with PXI-RT.

For safety reason, I would like to stop other mechanical and electrical facilities when communication between Windows host PC and PXI-RT Target lost for some reasons, such as Windows freeze and Network trouble.

So I would like to detect communication failure on PXI-RT, and then turn off mechanical relay.

Any advice would be greatly appreciated.

thanks regard

[ypi]

From where would you actuate the facilities? and how?

[ecleary42]

I would simply use a user a channel within your VS project called PC Watchdog and broadcast your host PC heartbeat to this using the workspace manager over the Veristand gateway

I would then have a simple watchdog "model" (I've taken to thinking of these as scripts as they are just a piece of code and dont have to be models) that outputs a boolean high when your watchdog is trippped

You could have an alarm watch this output from your watchdog model that when tripped runs a procedure that closes relays and such as desired

[ATarman]

I've used this watchdog method:  https://forums.ni.com/t5/NI-VeriStand/Configure-Watchdog-in-Veristand/td-p/2717405?profile.language=...

You could adapt it for your needs.  

[SWSanville]

I am still a little confused about the functionality of the watchdog timer when it comes to verifying that the computer and RT controller are communicating. It seems like the watchdog is looking at the RT controller and is making sure it is still looping. How does it pick up a disconnection between the computer and the controller? 
On some of our older stands, we are running a labview program on the PC in correlation with a program on a fieldpoint controller. Super easy to trigger an error and a shutdown on the controller when TCP drops out. I'm a bit confused about what is running on the RT controller and computer in the VeriStand environment and how to get the controller to bring itself to a safe state if communication is lost.

[_pepper]

We had an issue years ago where a test stand was running overnight, and the host computer crashed.  VeriStand was running a profile using Inertia, which existed on the host computer.  Since the SDF is compiled and deployed to the RT controller, all the host computer was doing was feeding commands to the controller as it moved through the profile. After the host computer crashed, the test stand basically "froze" in its current state, waiting on the next command.  Fortunately it froze at a point in the profile that was safe, but it easily could have done that at a point that would have eventually overheated the test stand.  Needless to say, my lab manager stopped allowing overnight testing on that test stand.

Fast forward to a more recent VeriStand project.  We created a " host heartbeat" that is a simple little Labview program that iterates a Boolean on/off at a 1 Hz rate and just runs independent of VeriStand.  That Boolean state is fed into VeriStand as a user channel, and a safety was created that opens a power supply contactor if that user channel doesn't change state after a certain amount of time.  This way if the computer crashes, so does that Labview program.

I'm sure there are a million other ways to do the same thing, but that worked for us a few years ago when faced with the same issue.  It seems like it would be fairly simple for NI to create a System Channel in VeriStand that is tied to something similar on the host computer, such that it could be used as a built-in watchdog.