Standards families
UML timing diagram
Lifelines as state waveforms over a shared time axis, with duration and time constraints marked.
uml.timing@1New DDN source
Why use it?
Some contracts live in the fourth dimension; the timing diagram is the only UML view that draws them directly.
When it helps
Real-time behaviour, protocol timing, SLA-shaped constraints.
How to read it
- Each row is one lifeline; the step line is its state over time.
- Braces and arrows annotate durations — they are constraints, not measurements.
What you need
- The lifelines and their states
- The time scale
- The duration/time constraints
Things to check
- Do not mix scales between rows without saying so.
- A constraint with no units is an argument waiting to happen.
Scope of this diagram
Declared timing with constraint validation; no simulation or schedulability analysis is performed.
Work with the converted example
- Open the viewer and select
timing. Inspect the rendered view and its source. - Open the designer. Keep the selected profile and inspect its legal palette and property controls.
- Change one displayed title or an appropriate data value. Apply the edit and check the resulting diagram.
- Run the verifier and review its diagnostics before moving complete content into review.
- Download your edited DDN source to retain the change.
The example uses the indentation-based ddn-next-1 dialect. The language guide explains reusable definitions, dotted data rows and explicit property blocks.