Best way to time different signals

Hey everyone, I'm a beginner so pleace be forgiving ;-)

What is the best way to time different signals? Let's say, I have an output that should be constant 1000 as long as my value X*Y (fed back values) is smaller than Z. If the product becomes larger than Z, I want the product as my output. And after 3 seconds, the output should be 0. What would be the appropriate way to do this?

I have googled for quite some time now but I can't get it to work. I managed the first part but probably not in a way it should be done...

Appreciate any input! Thank you!

[Jan]

The question is not clear.

[Matthias Bach]

Hey, I'll try to elaborate and maybe make it a little bit more abstract. Basically, I have one single output and I want the output to be 1000 unless a specific condition (X*Y<Z) is met. If the condition is met, the output should be Z, and after a time of 3 seconds has elapsed the output should be 0.

Does that make sense?

Answer 1

[Christiaan]

Dear Mathias,

I hope this piece of code can help you on your way. You may have a look at it.

The only point where you would have to modify the code, is for the case the time step is smaller or larger then one.

    clc;clear;close all

    t = linspace(0,800,800);
    dt = t(2)-t(1);
    x = t;
    y = sin(t/10);

    treshold = 5;

    for i=1:length(t)
        xy(i) = x(i)*y(i);
        if xy(i)>treshold
            state(i)=1;
        else
            state(i) = 0;
        end

        if dt*i>10

            if sum(state(i-2:i))==3
               xy(i) = 0;
               state(i)=0;
            end
        end
    end

    subplot(3,1,1);
    plot(t,state);
    subplot(3,1,2);
    plot(t,x.*y)
    subplot(3,1,3);
    plot(t,xy)
    grid on

Good luck! Christiaan

[Matthias Bach]

Hi Christiaan, thanks for your reply. This seems to do what I described but I need the whole thing in Smulink.

I have attached my current solution which unfortunateky is flawed.

With this, my output equals the incoming signal S. Then when V (variable which starts at 0) becomes bigger than X, S is subtracted from itself and the output becomes 0.

However, at a certan point V drops again and becomes lower than X. With my setup, the output then equals S. This is what I need to avoid.

V starts at 0 and rises -> output=S

V passes X -> output=0

V drops and becomes lower than X -> output=0 (currently output=S)

Thanks for everyone's support!