Symbolic representation of functional interactions between the signals of a system or a number of interacting systems. The functional dependence of the output signals on the input signals is shown as rectangles (blocks) and specific figures for certain contexts (e.g. circuits for addition points (Figure S 58). Each signal is shown by a line of action with an arrow at the top (DIN 19 226).
The functional relationship may be illustrated by descriptive equations (Pos. a (Figure S 59)), or in a graphical, normally qualitative representation (Pos. b).
Several hydraulic devices cannot be illustrated using reactionless blocks (e.g. if the flow rate through a continuously adjustable valve depends on the control signal and the pressure difference on the valve. In such cases, the action flow is divided into its individual functions, which are then connected as reactionless blocks (Figure S 60).

Figure S 58: Addition point (a) and branches (b)

Figure S 59: Descriptive (a) and graphical (b) representation of functional relationships

Figure S 60: Signal flow plan of a servo drive