Red Lion Controls 6HBWDOG1 Watchdog Relay SPDT

The Red Lion Controls 6HBWDOG1 Watchdog Relay SPDT is a rugged hardware-based heartbeat monitor that protects PLC/RTU-driven automation by providing a fail-safe shutdown when the monitored device stops pulsing its heartbeat. It uses a Form C (SPDT) relay to power the controlled load and includes heartbeat monitoring that, on timeout, can drive alarms or interlocks and even power an optional external lamp to indicate a fault. The module mounts on a DIN rail (snap-on, vertical alignment) and measures roughly 3.72 inches long, 1 inch wide, and 4 inches high, with M3 screw terminals for wiring sized 30–12 AWG and a recommended torque of 5 in-lb. It is powered from a 24 V DC supply and features front-panel indicators plus two recessed pushbuttons, including a bypass button to disable the heartbeat monitor when needed; three status LEDs convey operation, fault, and bypass states. The 6HBWDOG1 carries hazardous-location certifications and is designed for harsh industrial environments, backed by a very high MTBF of 4,018,881 hours at 40°C (MIL-HNDBK-217F2). In typical use, the device monitors the pulsing output of a connected controller and, if the heartbeat is lost within the configured timeout, the built-in Form C contact switches state to drive fault signals or initiate a safe shutdown, making it suitable for safety-critical applications in oil and gas, power, and process automation where reliable heartbeat verification is essential.