What diagram would be the best to describe the situation

Question

I am working on a software integrated with the hardware component. I need to create a simple diagram to express that:

1. Certain activity runs in a cycle (the device continously monitor a temperature)
2. When the temperature deviates from the baseline and remains so for 10 seconds, a function is called

I am writing a high level document and I am not sure how to capture this - UML diagrams do not seem to be suitable..but maybe an activity diagram?

Answer 1

Either activity diagram or sequence diagram (they are pretty much two views of the same thing).

(EDIT: whoops in earlier text I was confusing correlation diagram with activity diagram; they are really similar. Either it's been too long, or else there are just too many damn diagrams available. ;) )

Sequence diagrams have notation for looping; the message that follows the deviation would just come right after the loop.

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The boxes around an activity diagrams just become the boxes at the top of the sequence diagram. I used to really like activity diagrams, but came to find sequence diagrams easier to manage -- personal preference. BTW there's a good online tool for playing with sequence diagrams: http://websequencediagrams.com

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Also, you're describing a state machine, so a state diagram might also work well. The states are

• initial

• normal -- no deviation

• alert -- deviation detected, but less than 10 seconds

• trigger -- deviation detected for 10 seconds

...and then back to normal.

In any case, there are a few good choices. It's a small enough problem that you could do it each way and see what looks best.