EMS series electric actuator applies graphic lattice LCD which indicates the working status and alarm of the actuator in terms of torque, valve opening and limit setting etc.. The device contains automatic protection and diagnosis function and allows for adjustment, parameter examination and fault diagnosis without opening the housing of the working actuator even in hazardous area thanks to its explosion-proof function. The fieldbus communications card is adopted to form full-distribution computer coordinative work system to realize remote data collection, remote communications and remote diagnosis and maintenance. Featuring advanced technology, reliable performance and convenient operation, the actuator can be widely used in oilfield, power station, metallurgical industry, water treatment, paper making and chemical industry etc. and is thereby warmly welcomed by a large number of customers.