According to the EN 15714-2 standard, they comply with the class A operating mode classifications - that is, they are intended for Open - Close operation, where the actuator is required to drive the valve for the entire time of its stroke from fully open to fully closed or vice versa. They also meet the requirements of class B stepping/positioning, where the servo drive is required to occasionally drive the valve to any position (fully open, intermediate and fully closed). STANDARD servo drives can work in S2-10 (15) minutes mode or in S4-25% mode with max. 1200 c/h.
