This part of IEC 60534 is intended to permit a variety of positioning devices, which respond to a rotary motion, to be mounted on the actuator of a control valve, either directly or by employing an intermediate mounting bracket. This standard is applicable where interchangeability between actuators and positioners is desired. a) The standardized mounting in this standard defines the interface between the positioner and a part of the actuator having a rotary movement proportional to the control valve travel. b) This standard also covers the direct connection between the positioner feedback and the shaft (or its axial extension) of a rotary control valve. In such cases, the feedback rotation is coincident with the valve angular travel. c) The standardized mounting applies to those rotary actuators in which the rotary part mentioned in item a) has a maximum travel of 90°. Such a travel is coincident with the valve travel when a direct connection (see item b)) is performed. d) The standardized mounting is divided into two options. Figure 1 shows the basic design and defines the minimum requirements an actuator must fulfill to adapt most common positioners. The universal design in figure 2 offers more variations of positioner adaptation and positioner feedback connection. The positioner manufacturer should state which mounting design is required.