Electrically and electronic control apparatus and components for actuating, controlling and monitoring of hydraulic units, namely, hydraulic pumps or compressors, pressure and volume flow control systems for fluids, in the nature of pressure relieve valves, pressure equalizing valves, control valves, pilot valves, non-return valves, shutoff valves, overload protection valves, safety valves, regulating valves, reducing valves, throttle valves, filters for fluids, condensate separators, links, ...