manual actuation,
mechanical actuation (e.g. roller),
electric actuation (e.g. DC solenoid, proportional solenoid),
pressure actuation (e.g. by hydraulic pilot pressure),
combined actuation (e.g. by solenoid and pressure).
With pressure actuation a differentiation must also be made between direct and indirect actuation.
All valves must be moved by external forces from a rest position to a working position. There is a series of ways of achieving this action that in DIN-ISO 1219 are divided into: