How to fix "Signal Dimension" error message ?

Dear friends, I get the following message when I run my simulink model."Unable to determine signal dimensions. There is a loop consisting of 'ehasystemblockFuzzytest/EHA System/Add' that cannot be resolved because signal dimensions are defined by a cyclic relationship. Specifying the signal dimensions on Inport, Mux, Selector, Demuxes will help resolve signal dimensions in the loop. You can also use the Signal Specifications to define the signal dimensions."Any kind help ?"Any kind help ?

Answer 1

[Ashutosh Thakur]

Hi Thasvinthiran,

For blocks such as Inport, Mux, Demux, and Add, it is necessary to provide the signal dimensions. Without them, you can face issues with model simulation. As the error message indicates, by introducing the Signal Specification block, one can explicitly define the dimensions of the model. The following steps can be followed to use the Signal Specification block:

• Add a Signal Specification Block using the model browser.
• Double-click on the Signal Specification block; a dialog box will open.
• Set the Dimensions parameter to the desired value (e.g., [1] for a scalar, [n] for a vector of length n).
• Connect the block just before the signal path where this error occurs.

For more information on the Signal Specification block, you can refer to the following link

https://www.mathworks.com/help/simulink/slref/signalspecification.html.

Also, this error can occur due to presence of Algebraic Loops in the system. So you can also try to check and resolve any algebraic loops present in the model by referring to the following link:

https://www.mathworks.com/help/simulink/ug/algebraic-loops.html.

I hope this information helps you!