1

I've used Enterprise Architect (EA) to create pretty drawings and I've liked it for that purpose. I find that I have a lack of understanding on how diagram elements link between one another. What I find particularly frustrating is that there is very little documentation on how this linking works (although lots of documentation on how to draw pictures).

I would like to create a model of a simple processor/ECU (electronics control unit). Here is the behaviour:

  • An ECU has an instance of NVRAM (which is just a class) for an attribute
  • An ECU has a voltage supply (an analog value representing the voltage level supplied to the ECU)
  • An ECU has two digital input ports
  • Each digital input port fires signals when its value changes
  • the ECU has a state machine with three states; the state machine enters state 1 on entry; the state machine transitions to state 2 on a firing of either digital input ports so long as the ECU voltage supply is greater than 10 V
  • the ECU exists to state 3 when Voltage drops below 8; and goes back to normal processing when Voltage rises above 9

Can you develop a model that demonstrates how these elements interact? (Is there some reference I can read on how to understand this approach?)

Here's my first attempt:Classes

State Machine

enter image description here

I used a composite diagram in the ECU state so that I could have access to the digital ports diagramatically. I created a link for each port so that they "realize" class input PIn. I assume I can depict class attributes this way.

ECU State Machine

I "create a link" so that the DIO triggers realize the DIO ports. Not sure I can do this.

The class state machine is where I get lost. Not sure on how to create a trigger for ECU.Voltage < 8.

Frank C.
  • 7,758
  • 4
  • 35
  • 45
Jordan McBain
  • 275
  • 2
  • 11
  • It seems understanding how UML's event modelling works is a necessary prerequisite to this. http://www.pvpsiddhartha.ac.in/dep_it/lecturenotes/OOAD/unit-4.pdf – Jordan McBain Jun 20 '18 at 20:44
  • OOh and this: https://www.sparxsystems.com/enterprise_architect_user_guide/14.0/model_domains/reception.html – Jordan McBain Jun 20 '18 at 20:53
  • https://stackoverflow.com/questions/24681328/how-to-represent-event-in-a-uml-class-diagram – Jordan McBain Jun 20 '18 at 20:56
  • Your question is a tiny bit too broad. I suggest you have a deeper look into SysML since it has been designed for that purpose. – qwerty_so Jun 20 '18 at 21:09
  • I agree that the deficiency that generated this question was a lack of understanding of UML. The question is not how to do system modelling but how to create an EA model with a simple set of requirements that captures all the desirable linking. – Jordan McBain Jun 20 '18 at 21:13
  • Basically you should understand what modeling means. SysML is a dialect which targets people doing exactly those things you describe here. Talking their language will help you in creating a meaningful model. I know it's tough, but just google for SysML and read a few papers (there are quite a number of good examples). That's better than trying to re-invent the wheel with UML (which actually supports SysML by use of a profile). – qwerty_so Jun 20 '18 at 21:20

0 Answers0