Analog/Digital outputs state after a crash

[joe90]

Hi,

I expose you my problem:
I use a PXI and labview in order to carry out the supervision of a test bench.
Analog outputs are used for the ordering of the power converters and digital outputs are used for relays of emergency stop.
Unfortunately at the time of a crash of Windows or PC, the PXI keeps the last values received on the outuputs whereas I would wish that they take again their initial state as when the PXI is turn off.
Of course, this cannot be done by software in labview since the PC crashed, but there is an option or configuration of the PXI or Mxi-4 card so that the exits are conditioned with labview operation and not the PXI operation.
I.e. i would want that the outputs take again their initial state when labview is turn off and not when the PXI is turn off.

thank you very much,

[Kerouac]

Hello Joe90,

I don't know which devices are installed on your PXI chassis but Industrial DIO devices support the DAQmx Watchdog feature. In the event of the unexpected failure of some component of the system, the Watchdog fail-safe mechanism will take over and place the system into a known safe-state. Look at the following tutorial for more details.

* The Industrial Feature Set: Watchdog Timers: http://zone.ni.com/devzone/conceptd.nsf/webmain/b1850930b434eaf786256e6700019b48

It seems that you are using MXI-4 extension. MXI-4 bridge does not provide hardware mechanism (like RT watchdog for PXI RT controller) in order to put all the PXI system in a safe configuration. Basically, PC crash or LabVIEW crash cannot be detected by software. Only hardware can detect a loose of communication between the software layer and the hardware layer (watchdog mechanism). Of course, when you leave your LabVIEW application, your should quit the application properly by placing the system into a known safe-state.

I hope this will help.

Matthieu G.

[joe90]

Thank you very much Mathieu,

the watchdog perfectly functions thanks to your assistance.