The point defence array is point defence mounted on a station: rapid guns on a steel plate mount, turned by motors, aimed by sensors and circuits. It fires rounds from the station's hold at close range.
Each minute, before other weapons fire, it shoots down a torpedo in flight at the station, or at anything of its side close to the station, once the torpedo has closed to close range. Otherwise it fires at strike craft, and stops bombers on their run. Like a ship's point defence, it cannot aim at anything larger than a bomber. It fires under the station's stance, like the defence battery.
It draws power all the time, so the station's generators burn fuel to keep it live. An unpowered array does not fire. A Forward HQ or a combat station can hold one.