The program running on the personal computer constantly triggers a counter on the watchdog card. If the software runs properly, the program resets the timer. If a system crash occurs, the program cannot reset the counter. In this case, the card waits for a predefined time and then switches a relay on the card (watchdog event) to reset the computer or trigger an alarm.
The basis are the two watchdogcards WATCHDOG1/ PWDOG1 and WATCHDOG2/PWDOG2N. While the WATCHDOG1/PWDOG1 has one relay that can for example be connected with the computer's reset switch, the WATCHDOG2/PWDOG2N has another switching relay that can be used either to switch on or switch off. This can be used for example on a mailbox system to switch off the modem for a short time or to use the board in a motherboard without reset switch ( ATX Power supply ).
The card WATCHDOG3 is a further development. It has two switch-over relays that switch different objects when the watchdog event occurs. The time span between the supposed crash and the switching of the relays can be set to between 3 milliseconds and 2 hours. The card can also switch a second reset after a freely choosable time in case the first reset failed.
Watchdog cards are used for the supervision of programs that have to be permanently in operation, for example in process or production supervision, in other critical applications or in mailbox programs.
A mailbox system must be on line permanently. You can reset crashed systems and protocol the crashes with our watchdog cards. Additionaly, a watchdog2 card can switch off the modem for a short time.
System crashes can have critical consequences on process control systems. To trigger an alarm and restart the control computer, use our watchdog cards.
To guarantee a permanent supervision of processes of all kinds, a watchdog card can be used.
No one is there if the server crashes at night? Wrong! There is the QUANCOM watchdog card! With additional hardware and appropriate proramming, it can alarm the maintenance service.
Uninterrupted Power Supply that guarantees a running system for several minutes if there is a power failure.
Relays are used as switches depending of the state of a circuit.
If a relay on our cards is addressed, the contact either opens or closes so that a connected circuit (with external power supply) is switched on or off. Please note that the external current must not be too high because it then overloads the relay.
Switching-on relays close circuits, Switching-over relays open or close a circuit.
Flip-Flop that is used here as memory for the chosen timout time, similar to a data register in a micro processor.
A program running in the background which is not affected from the running application software.
Time span after which the relay switches the reset.
The watchdog time is the time in which the software must send a signal to the board to prevent the relay from triggering. If the board receives no signal, the watchdog event takes place, and the watchdogcard switches the relays. (same as timeout time)
If the counter runs down without a reset from the software, the relays are triggered. This process is called watchdog event.