SIMATIC S7-HiGraph – Description of asynchronous processes using state graphs

S7-HiGraph is a STEP 7 option for automating function units at equipment levels such as valves, motors, or workholders that can assume a clearly defined number of states (e.g. open, closed).  Typically, only a few processes are repeated (e.g. switching on/off, traversing up/down). Machines and plants that are mainly made up of such function units are, for example:

• Assembly cells;
• presses with simple functions such as clamping, pressing, releasing;
• drill units without NC functionality;
•  transfer lines and
• conveyor systems.

Mode of operation
The following procedure replaces the actual programming:

• Possible function unit states are defined
• The programmer generates the program by graphically connecting the states and defining the step enabling conditions.

The decisive advantage is that the program structure is geared to the process-oriented objects and can therefore be easily understood. Once the state diagrams have been generated, they can be reused as many times as required and also be modified centrally. Process diagnostic functions are integrated as in S7-GRAPH.

Depending on the application, up to 50 % less engineering overhead can be achieved with S7-HiGraph. At the same time, the program execution times are reduced when S7 HiGraph programs are executed. Thus the operating times of a machine can be reduced by up to 10 %.