Modulating Actuators

Rotork’s new CMA all-electric modulating actuators are suitably sized for linear, quarter-turn and rotary control valve and pump applications requiring precise position control and continuous modulation. They can be powered by single-phase or direct current supplies, eliminating the need for air hoses and compressors used with similar pneumatic control valve actuators. Set-up and configuration is easy via push-buttons and an internal six-segment LCD display. Resolution is 0.25% on linear and quarter-turn applications and 2 degrees on the multi-turn configuration. Other features include a permanently lubricated and maintenance-free drive train; a 4-to-20 mA loop-powered, feedback signal; and digital communication options including HART®, Foundation Fieldbus, Profibus, Pakscan, RIRO and Modbus. The new CMA actuators complement Rotork’s CVA electric control-valve actuators, which were introduced in 2008 and are operating in thousands of process control applications throughout the world.