During the course of the task “Find Timing Properties” the solution is annotated with events, event chains, and timing constraints as shown in the lower part of Figure 1 – depicted by the red colored event chain drawn above every element of the solution. On this level of abstraction the given event chain including its latency timing constraint is broken down into seven subsequent event chains, playing the role of event chain segments, and latency timing constraints are imposed on those seven event chains respectively event chain segments. In addition a periodic event triggering constraint is imposed on the event that is observed at the provided port of the basic software function called “Sensor”, because the solution provides data for example periodically.
In this example, an event chain referring to the second provided port of logical device manager called “Actuator” and the second required port of the [design] function/component called “F1” is not specified, because this path is considered unimportant with regard to timing. Note that in other cases this path could possibly have a significant impact on the dynamic behavior of the system, e.g. in a control application, and then must be considered accordingly.

Figure 1: The simple example to demonstrate the use of the TIMMO-2-USE Generic Method Pattern annotated by timing information
Furthermore, an event chain can be specified referring to an event that is observed at the required port of the hardware function called “Sensor” and an event that is observed at the provided port of the hardware function called “Actuator”. And a timing constraint is imposed on this event chain. This timing constraint – the property and the value – may be the same as the given one [timing requirement].
The values of all those timing properties are determined, too, and for good reasons one could specify the following latency timing constraints:
1. A latency timing constraint imposed on the combination HF, BSF, and LDM called “Sensor” of 30 ms including a variation of -2 ms and +5 ms resulting in a time range of 28 ms to 35 ms.
2. A latency timing constraint imposed on the function/component called “F1” of 20 ms including a variation of -1 ms and +2 ms resulting in a time range of 19 ms to 22 ms.
3. A latency timing constraint imposed on the function/component called “F2” of 45 ms including a variation of -5 ms and +3 ms resulting in a time range of 40 ms to 48 ms.
4. A latency timing constraint imposed on the combination LDM, BSF, and HF called “Actuator” of 25 ms including a variation of -2 ms and +10 ms resulting in a time range of 23 ms to 35 ms.
The following table summarizes the values of all determined latency timing constraints.
Component |
Latency Timing Constraint |
Minimum |
Maximum |
HF, BSF, LDM “Sensor” |
30 ms, -2 ms, +5 ms |
28 ms |
35 ms |
F1 |
20 ms, -1 ms, +2 ms |
19 ms |
22 ms |
F2 |
45 ms, -5 ms, +3 ms |
40 ms |
48 ms |
LDM, BSF, HF “Actuator” |
25 ms, -2 ms, +10 ms |
23 ms |
35 ms |
|
Totals: |
110 ms |
140 ms |
Additionally, the value of the periodic event triggering constraint that is imposed on the event observable at the provided port of the basic software function called “Sensor” is 10 ms including a variation – jitter – of 2 ms resulting in a time range of 8 ms to 12 ms.