The Watchdog timer works by having the device constantly receive confirmation that the computer is still functioning properly or that the device is still connected to the network. In the case of a PXI system with remote control via MXI, a lost MXI connection could result in unexpected Watchdog behavior and therefore improperly implemented Watchdog states. Note that the NI-DAQmx Watchdog feature is meant to protect a system from software errors and hangs. You can configure the Watchdog timer for your device to take over the output channel and place the system into a known safe-state if an undesired event occurs such as a software hang that causes a confirmation to not be received within a programmable time-out period. If the system is not operating as intended, it can be placed in a safe-state. The Watchdog timer is used to monitor and identify if the system is operating correctly. The Watchdog timer provides a method for supplying such a mechanism.
In the event of the unexpected failure of some component of the system, the fail-safe mechanism takes over and places the system into a known safe-state. Critical systems typically require redundancy or fail-safe mechanisms of some kind.
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