This section of IEC 60534-6 is intended to permit a variety of positioning devices, which respond to a linear motion, to be mounted on the actuator of a control valve, either directly or by employing an intermediate mounting bracket. This section is applicable where interchangeability between actuators and positioners is desired. The following parameters define the intended applicability of this section for the guidance of manufacturers and users. – The standardized mounting applies only to positioners which are mounted on the side of the actuator. – The standardized mounting applies in general only to actuators which have a travel from 10 mm through 100 mm. – The standardized mounting is designed to cover three basic types of actuator designs (see figure 1): a) those with some form of cast or fabricated yoke to connect the actuator power unit to the valve; b) those which use some form of central tube yoke to connect the actuator power unit to the valve; c) those in which the yoke incorporates two or more columns or pillars to connect the actuator power unit to the valve.