该系列是一种采用多弹簧结构，重量轻、体积小、性能高、输出力大的气动薄膜式角行程执行机构。其工作原理为：由调节仪表来的电或气信号经定位器转换而成的气压被输入到膜室内，作用于膜片上产生推力，使推杆移动，同时压缩弹簧直至和弹簧的反作用力相平衡，推杆的直线运动经曲柄机构转换成角行程输出，使输出轴转动到预定的位置。

该系列执行机构与定位器配合使用可实现高精度的位置控制。

This Series features high performance, high power diaphragm actuators of a multi-spring type that are compact and light. With a positioner that receives pneumatic or electric signals, air-pressure is exerted on the diaphragm. Balancing the force of the air-pressured diaphragm and the force of the compressed spring creates a linear motion output. The scotch-yoke system converts the output to a rotating force and provides positioning to a required angle.

This Series is designed to function with a positioner except in on-off control.