Finding the value of a signal before and at the time of the event in Simulink? Other than using "ToWorkspace' block of simulink.

I have simulink model IEEE39 Test system (Transmission Network System). I want to calculate a factor K = Δθr - Δθs ,so Δθr= regional angle behaviour and Δθs= system wide angular behaviour, where Δθr = θrp - θra i.e. (θrp = pre-event value and θra = at the time of event value) . Similary for the Δθs , it has pre-event system value and 'at the time of event' value. So, when I start the simulation and add an event (a fault or any disturbance), I need to calculate this factor while the simulation is running. I don't want to send the values to workspace and run the simulation twice therefore need suggestions/assistance in this regard. Thank you.

[Taimoor Khan Mehmand]

So basically I have a signal theta and I want to calculate it's value before the event and at the time of the event.

Answer 1

[Benjamin Thompson]

Use the event to trigger an enabled subsystem. Theh output of an enabled subsystem only changes when or while it is triggered, so you could connect that to a display or scope block. Possibly two enabled subsystems depending on how you are defining the event signals.