How can I generate an output pulse in Simulink every time a function-call trigger occurs?

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Danny S
Danny S 2022-3-3
回答： Danny S 2022-3-4
I have an existing Simulink model from a customer that uses function-call semantics as event triggers on Stateflow charts, amongst other things.
For our current purposes, I need to be able to generate a simple output pulse when a function-call trigger occurs, such that:
-> At the function call trigger, we set the output to value 1
-> After a fixed period of time (e.g. 1ms), the output value is set to 0.
And this then repeats whenever the function call trigger next occurs.
I tried setting up a stateflow chart as follows:
And although this does generate a pulse, the transition from High to Low state only occurs when the E event occurs, rather than 1ms after when the initial E event occurred. That is, it is obvious that the chart is going to sleep in between the E function-call events.
The E events are around 200ms apart, and each pulse of 'y' is also the same width - when I want it to only be 1ms wide when y=1.
Is there a way to change the chart settings so that it stays awake until the transition from High back to Low has occurred?
Or could I acheive the same behaviour using a Function-call subsytem instead of a Stateflow chart? Either is fine for me.
(The overall model uses a Variable solver, as the block generating the function-call pulses requires it.)

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回答（1 个）

Danny S
Danny S 2022-3-4
So after some experimentation, here's a solution that seems to be working for me.
The chart:
This lives inside the following subsystem:
The FunctionCall input comes from the customer block that generates occasional function calls. The 1ms function call has a sample time of 0.001. These are muxed to the input events of the chart as E and M1 respectively.
Within the chart, the function call E will transition from Low state to High state and set y=1; Then, after 2 instances of the M1 event, we transition back to low and set y=0.
It does seem odd that I need to wait for 2 instances of M1, rather than just having the transition as M1 - but given that E and M1 will both occur at the same time (generally, E is at a microsecond boundary), without the after(2, M1) transition, I could see the state transitions happening by using debug breakpoints and stepping, but they were both occurring at the same time step thus the pulses were 0 time in width.
With the above chart, I can see (via a Scope of the value of y) that I'm getting y pulses with width 1ms, and they start at the same time as E.
If someone has any better solutions, please feel free to submit them too!

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