[20] Circuit symbols for manual operation
The switching position of a
directional control valve can be changed by various actuation
methods. The symbol for the valve is accordingly supplemented by
a symbol indicating the actuation methods shown, such as
pushbuttons and pedals, a spring is always necessary for
resetting. Resetting can, however, also be achieved by actuating
the valve a second time, for example in the case of valves with
hand levers and detents.
The various actuating methods possible are listed in DIN ISO 1219.