DKZ and ZKZ linear-travel electric actuators serve as one of the actuator units within the DDZ electric unit combination instrumentation. When paired with ZPE servo amplifiers, these actuators receive standardized 0-10mA (or 4-20mA) signals, converting the current input into corresponding linear displacement. This enables automatic manipulation of control valves to accomplish automated regulation tasks. When paired with the DFD electric operator, the DKZ and ZKZ linear-travel electric actuators enable seamless manual-to-automatic switching in control systems without disturbance.