There are three competing standards&colon; DiSEqC, USALS, and 36 V positioners. These typically incorporate ABB or FANUC robots with Wolf's own robotic positioners. Control valves are normally fitted with actuators and positioners. The focal plane accommodates 5,000 small computer controlled fiber positioners on a 10.4 millimeter pitch. Instruments include Pressure Transmitters, Coriolis Flow Meters, Valve Positioners, Buoyancy Level Transmitters and Temperature Transmitters. These are the fast head positioners for rigid-disk ("hard disk") drives. Positioners are typically used when a valve requires throttling action.