Block diagrams are essentially a very simple format of diagrams. A variety of commonly used shapes and connecting lines, rules of construction and actions pertaining to them, make Block diagram a versatile and flexible tool for many forms of industry. Another advantage is the ease with which Block diagrams can be constructed, especially if you use professional diagramming software.
ConceptDraw DIAGRAM software is an example of purpose built application designed with the form of process modeling in mind. It includes Block Diagrams solution from Diagrams area of ConceptDraw Solution Park for easy drawing professional-looking simple diagram - Block diagram, and a lot of other useful solutions for designing variety of other types of diagrams, schematics and flowcharts (Line graphs, Bar charts, Organizational charts, Histograms, Pie charts, Process flowcharts, Fault tree analysis diagrams, Scatter plots, Venn diagrams, Bubble diagrams, etc.). The RapidDraw functionality of ConceptDraw DIAGRAM lets create new objects and their connectors in just single-click.