Transfer Function block in Simulink for variable size input

Dear Tech Support,

The error occurs at the Simulink transfer function block.

My error message roughly:

Simulink cannot propagate the variable-size mode from the output port 1 of the (previous block) to the input port 1 of transfer function".

What can be done in order to make the transfer function block comply with a variable size input ?

The input of the transfer function block is a signal, represented by a (1 x 500) vector.

Thank you in advance !

Sincerely,

Miklos

Answer 1

[Prateekshya]

Hello @Miklós,

The error message you are encountering in Simulink indicates that the Transfer Function block is not designed to handle variable-size signals directly. Here are some steps you can take to address this issue:

1. Fixed-Size Signal: If possible, convert your variable-size signal to a fixed-size signal before it reaches the Transfer Function block. This can be done by ensuring that the dimensions of the signal are constant throughout the simulation.
2. Use a Selector Block: If your signal can be broken down into smaller, fixed-size portions, use a Selector block to extract a fixed-size portion of the signal to pass through the Transfer Function block.
3. Buffer Block: Consider using a Buffer block to convert the variable-size signal into a fixed-size signal. The Buffer block can be configured to output a signal with a fixed number of samples, which can then be processed by the Transfer Function block.
4. Custom Function: If the above solutions do not fit your needs, you might consider implementing a custom function using a MATLAB Function block. This approach gives you more control over the input and output sizes and allows you to handle variable-size signals more flexibly.
5. Check the Model Configuration: Ensure that your model is configured to support variable-size signals if you are using them elsewhere. This can be done in the Model Configuration Parameters under the "Solver" and "Data Import/Export" sections.

I hope this helps!