HawkEYE monitors the frequency of the local mains electrical supply and reacts when that frequency drops below preset thresholds.

There are 3 relays built into HawkEYE. These relays are not connected by default and are only switched to the connected state when the frequency reaches one of three preset values.

Relay 1 will turn on when the frequency falls to 49.7 Hz, Relay 2 at 49.6 Hz and Relay 1 at 49.5 Hz. The Relays will turn on when the frequency has remained below the threshold for 0.2 seconds. It will only turn off when the frequency has returned above the threshold for 0.2 seconds. These smoothing values are to prevent instability for attached devices when the frequency fluctuates around the thresholds.

The threshold frequencies and the Relay reaction times are preset during manufacture. Different values can be programmed before delivery if requested.