Rules

1. Don't “improve” the method by adding things. It's simplicity is its strength.
2. Diagrams shall have contain 3 to 6 Functions
3. All functions contain:

Note:

Always at least 1 control and 1 output.

The IDEF Spec doesn't actually limit the number of lines on each side, I picked 3 for my article. Maybe 4 would be better.

For all Diagrams other than the Context Diagram...

The Context Diagram has only one block. Also some explanatory text.

Source

The IDEF0 Spec

IDEF0 Functional Modeling

Related Notes

IDEF0