Product/Service
PCI-WDG-CSM
- Watchdog timer to detect computer malfunction
- Relay and electronic "Reset" outputs
- Automatically detected under Windows95/98/NT
- No base address or IRQ switches to set
- Optional computer power supply monitor
- Optional computer temperature monitor
- Optional computer temperature measurement
- Optional fan-failure detection, watchdog timeout buzzer
- Optional fan speed control
FUNCTIONAL DESCRIPTION
This multifunction card is designed for use with PCI-Bus computers. It continuously monitors critical PC functions. When a fault occurs, the card automatically generates outputs that can be used either to initiate corrective action or to generate alarms.
The Watchdog Timer offers excellent protection from CPU malfunctions at low cost. If your applications program is set up to communicate with the watchdog circuit at periodic intervals and this "prompt" is missed, the watchdog can be programmed to initiate a Reset (Reboot). If the reboot is successful, operation may be returned to the previous application program and, if the failure was temporary, proper operation is resumed. If, however, the failure is persistent, then the watchdog will continuously reset the computer.
If you are operating under Windows95/98 this hardware reset does not, in itself, permit an automatic restart. (Under WindowsNT an automatic restart can occur but files may become corrupted during restart.) For this situation, the PCI-WDGCSM can generate an interrupt prior to the watchdog timeout (Timeout Imminent). That interrupt can notify your Interrupt Service Routine which you can set up to perform a graceful shutdown of Windows. If that graceful shutdown fails and the watchdog timeout period expires, then the Reset signal will reset the computer as if the Reset button was pushed. If an Interrupt Service Routine is not written, Windows will not automatically restart because it will wait for the operator to press a key to allow "scandisk" to run. This can be bypassed by using a Microsoft supplied Utility program. If you wish to know more about that, contact us.
Watchdog timeout periods can be programmed from four microseconds to over 30 minutes. Of course, the shorter the watchdog time selected, the less time a faulty computer can have to cause damage.
ACCES I/O Products, Inc., 10623 Roselle St., San Diego, CA 92121-1506. Tel: 858-550-9559; Fax: 858-550-7322.
