Systems and methods for automatically or remotely rendering a solar array safe during an emergency or maintenance. A watchdog unit is disclosed for monitoring a signal from a central controller. If the signal is lost, interrupted, or becomes irregular, or if a shutdown signal is received, then the watchdog unit can shut down one or more solar modules. Shutting down a solar module can mean disconnecting it from a power bus of the solar array or lowering the solar module voltage to a safe level.