State Machine Transitions

Syside How-to Guides
,
1

Hello,

I’m trying to model state machines and I’m wondering if:

  1. Is it possible to create transition between states crossing hierarchies?

  2. Can I have two transitions (in the same direction) between two states?

Below is what I’ve been trying.

Thanks!

Tom

state def StateMachine {

  entry;
  then Unpowered;
  state Unpowered;
  then Powered.Standby;
  
  state Powered {
    state Standby;
  }
}
2

Tom,

State definitions (state def) declares the state machine itself; states within are usages (just state).

Within a state are three actions, entry, do, and exit, so entry; is inappropriate. Consider this hierarchical state machine example by Richard Page, leader of the Execution Working Group of OMG’s Systems Modeling Community:

item def TriggerItem;
state def ContextState {
	state MyInterruptableState {
		do action wait {
			accept after 5 [SI::s];
		}
		
		state one;
		state two;
		
		transition t1 first start accept after 1 [SI::s] then one;
		transition t2 first one accept after 1 [SI::s] then two;
	}
	transition tStart first start then MyInterruptableState;
	transition tInterrupt first MyInterruptableState accept TriggerItem then done;
}
case 'test state interruption' {
	subject s : ContextState;
	
	// As per minimum time rule, executed immediately before any "waiting"
	send new TriggerItem() to s;
}

MD messed up the formatting, but you can get the idea.

3

Thanks for your reply! I tried out your example, I don’t think it’s answering my question (unless I am not understanding it). I’ve attached a diagram of my above example using SysML v1. How can I model this state machine in v2?

image
image1038×510 10.2 KB

4

It took a while, but I think I have figured it out (it is supposed to be the SysML v2 version of the image above).

package StateMachineExample {

    item def TurnOn;
    item def SecondTurnOn;

    state def StateMachineExample {
        state Unpowered;
        transition first start then Unpowered;
        state Powered {
            state Standby;
        }
        transition first Unpowered accept TurnOn then Powered.Standby;
        transition first Unpowered accept SecondTurnOn then Powered.Standby;
    }

}