Delay block with vectors

Question

Laurent Dalbies 2019-2-28

1
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https://ww2.mathworks.cn/matlabcentral/answers/447473-delay-block-with-vectors

评论： Ibrahim Guenoune 2019-3-13

test_delay.slx

hello all,

I get an error when I use the discrete "Delay" block with input data as a vector.

"In block 'test_delay/Delay', the size of IC is incompatible with the delay length. When IC is not scalar, the last dimension number of IC should equal to the delay length value. However, in this block, the last dimension number of IC is 3, but the delay length value is 100.

Component:Simulink | Category:Model error

Error in port widths or dimensions. Output port 1 of 'test_delay/Mux' is a one dimensional vector with 3 elements."

I understand that the delay block support the use of scalars and vectors. Apparently the problem is related to the initial condition but I don't really understand why. Can anyone help ? Attached is my test model.

Thanks & regards

Laurent

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Ibrahim Guenoune 2019-3-12

Hello Laurent Dalbies,

I'm writing you for asking if you have resolve this problem, if is the case, could you inform how you were doing ?

Thanks

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Answer 1

Mauro Fusco 2019-3-12

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https://ww2.mathworks.cn/matlabcentral/answers/447473-delay-block-with-vectors#answer_365063

编辑：Mauro Fusco 2019-3-12

test_delay_solution.slx

Hi,

see the picture below for a solution. The initial condition has to be set consistently with the number of samples of the delay. As you are specifying 5 samples, also the IC has to be consistent with that. Assuming that you want to keep the initial value

for the first 5 samples, I have used vector concatenate to build the matrix of IC. You can change this, by specifying different vectors to concatenate. Also, note that you need to change a parameter in the initial condition block, which was set to 100. "When IC is not scalar, the last dimension number of IC should equal to the delay length value" means that you have to set this parameter to 5.

Attached you also find running simulation file.