Implement watch dog for USB 6251

[ediorz]

Hi,

I am pretty new to NI DAQmx and USB 6251 so I might be asking a question that has a obvious answer here....(also if I should post this question somewhere else please let me know)

I am trying to implement a watch dog timer that will trigger a digital output (static or waveform) to a signal light when it expired

From the spec for USB 6251, I can see that it does not have a built in watch dog timer that I can use..

Therefore, is it possible to implement my own watch dog timer (hardware not software) with this device??

I am programming using C# .NET 4.0 (without measurement Studio so I am only using the library provided) which I can see the methods for watch dog but cannot use due to hardware spec..

Maybe my best thing to do is buy another model that has a built in watchdog timer??

Thanks in advance,

Edward

[ediorz]

I should add more information for this...

So what I am trying to do is as follows:

1) have a watch dog timer that is configured to turn on a warning light when expired

2) have the software side to keep up resetting the time so it will not expire

3) when software crashes or anything events that stops the setup, the watch dog will trigger ths warning light (i.e. set the signal for digital out)

so is the above doable for USB 6251???

Thanks,

Edward Peng

[Joshua-B · Accepted solution]

Hi ediorz,

A Watchdog Timer is implemented in hardware so that if communication is lost with the software then you can set signals into a safe state.  If you were to implement something similar in software, there is no way to set the state of the outputs in the event of a software crash (since the software is what is setting the state).  If you need to have Watchdog Timer functionality, I would recommend purchasing different hardware that can implement this in hardware.  Hopfully this is a helpful explanation!

[ediorz]

Hi Josh,

Thanks for the reply

I guess I will have to look into a different device that can implement this in hardware

Thanks!!!

Edward