D1 Watchdog Relay Switchover

The Watchdog Relay Switchover WRS-D1 is intended as watchdog circuitry for two PCs. In case of a failure of one PC the WRS-D1 will switch over the VGA signal and RS422/RS485 signal to the other PC. The switchover is performed with high reliable relays with gold contacts. In case of complete power loss the relays will switch to PC A per default The WRS-D1 will receive heartbeat signals from both PCs via the RS232 DTR Modem Control Signals. Typically the main control application will generate the watchdog signals. When the heartbeat signal is lost for more than 15 seconds and the heartbeat signal is present for the other PC, the WRS-D1 will switch to the other PC. There is an automatic power on delay after a PC has been switched on. Within 5 minutes after power on the watchdog is disabled, allowing the Operating System and applications to start properly. The selection state is signaled to the selected PC by a connection between the DTR and CD signals of the RS232 interface. The WRS-D1 will send an alive signal to the RS232 DSR line to both PCs. This signal will be 8 seconds high and 2 seconds low. This signal may be used by the control application in the PCs to prove that the WRS-D1 watchdog circuitry is healthy and working.

It also has Manual Switch which allows switching manually to PC A or PC B. In the mid position (Auto) the switchover is controlled by the watchdog circuitry.

• Automatic power-on delay after a PC has been switched on
• Automatic alive signal to the RS232 DSR line to both PCs
• Easy to use
• Large number of connections
• USB power supply