delay time - s function
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hello sir, i use level 1 S-Function in my simulink model. I need s function to wait for 2 sec, then collects the measurements. How i can do that ?
4 Comments
Aquatris
on 27 Aug 2018
You can use a switch block. The two inputs to the switch can be "constant 0" and the actual signal. Then you will attach "clock" block to the decider and set the switch block to give constant 0 as output if t < 2 and actual signal if t > 2.
Answers (1)
Walter Roberson
on 27 Aug 2018
Aquatris's solution is the correct one in many cases.
However, if you are feeding into a controller, then the controller might be taking the differentiation, and the sharp change between 0 and non-zero would be a problem for differentiation. Therefore for you situation you should probably instead use an enabled subsystem https://www.mathworks.com/help/simulink/ug/enabled-subsystems.html, in which the control signal is the output of a comparison block between the clock and a constant block which is the enable time.
5 Comments
Aquatris
on 10 Sep 2018
You can also use a "rate transition" block, which samples the signal in a different time than the simulation time. See image below where I use a sine wave as the source signal and the rate transition block allows to sample it every 2 sec (Zero order hold) and ignores the changes if 2 sec had not passed. Is this what you are trying to achieve?
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