You can set the correct frequency for Arecont units to prevent flicker caused by lightning power line frequency.
The frequency setting has no effect when the dominant light is sunlight. This setting
also loses effect if the camera’s Low Light Mode exposure option is
set to High Speed, and the Short Exposures
value does not match the power line frequency. The Short Exposures
value matches the power line frequency when it is close to a multiple of 8.3 ms for 60 Hz,
and a multiple of 10 ms for 50 Hz.