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Identical models in MATLAB and Simulink do not match each other

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I am noticing that discrete-time models I am using in Simulink do not match the same response in the Matlab environment.
For example.
sys = tf([3.332 4.679], [1 30.97 45.5], 'OutputDelay', 0.1);
sysd100 = c2d(sys,0.01)
sysd200 = c2d(sys,0.005)
opt = stepDataOptions('StepAmplitude',200);
step(sys, opt), grid on; hold on;
step(sysd100, opt); hold on; step(sysd200, opt);
sys is my continuous transfer function, sysd100 is the same function sampled at 100 Hz and sysd200 is sampled at 200 Hz. The step response is expected. I then reproduces the same transfer functions into Simulink, but am getting the following results
I am not an expert in Simulink so I ask the community on what would be the reason for this behaviour.
Thank you, Daniel

Answers (1)

Daniel Gelman
Daniel Gelman on 22 Aug 2016
Always be aware of significant figures. Even 0.0001 can make a difference in differential equations.

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