why the error in the following " set_param(​BlockName,​BlockParam​eter,Strin​gValue); "

I am trying to change the parameters inside a Linear Transfomer Magnetization resistance and inductance [Rm(pu) Lm(pu)]:. These parameters are named as RmLm when I view the mask. I am using Embedded MATLAB function block to set the parameters using set_param. The full code for MATLAB function block as following:

function ChangeParam(u) %#codegen

coder.extrinsic('set_param');

coder.extrinsic('num2str');

BlockName = 'Transfomer_Dynamic/Linear Transformer';

BlockParameter = 'RmLm';

StringValue = [num2str(u) ' ' num2str(u)];

set_param(BlockName,BlockParameter,StringValue);

I am getting the following error and I tried to find the debug but I am not be able. could anyone help or recommend me any suggestions ?

Cannot change parameter 'Magnetization resistance and inductance [Rm(pu) Lm(pu)]: (RmLm)' of 'Transfomer_Dynamic/Linear Transformer'

while simulation is running Error in 'Transfomer_Dynamic/MATLAB Function' (line 10) set_param(BlockName,BlockParameter,StringValue);

Answer 1

[Walter Roberson]

Only tuneable parameters can be changed while the simulation is running.

In some situations it is workable to run a MATLAB function that sets parameters, then invokes sim() with a stop time, then examines results, and loops back to try different parameters.

[Willim]

How can I know if the parameters is tunable or not. If the parameters are not tunable , What is the way around it ? Also, could I use allowpcode in this case ?

[Walter Roberson]

https://www.mathworks.com/help/sldrt/ug/tune-block-parameters-and-matlab-variables.html and see the (old) discussion at https://comp.soft-sys.matlab.narkive.com/Lj55e2UO/how-to-programmatically-set-a-tunable-parameter

[Willim]

Is there any way to make the untunable parameters as tunable ? I am not trying to tune it to the right value. I want to investiagte the behaviour for the transfomer while the Magnetization inductance (Lm) is changing over the running time baecuse of the change in the load.

[Walter Roberson]

I noticed that previous link is for Simulink Desktop Real-TIme, which has more restrictions than Simulink.

https://www.mathworks.com/help/simulink/ug/using-tunable-parameters.html#bu1up6v-1

[Willim]

>> paramInfo.RmLm

ans =

struct with fields:

Prompt: 'Magnetization resistance and inductance [Rm(pu) Lm(pu)]:'

Type: 'string'

Enum: {}

Attributes: {'read-write' 'read-only-if-compiled' 'link-instance'}

This emphsizs that Magnetization resistance and inductance [Rm(pu) Lm(pu)] is not tunable. It cannot be changed during simulation running.

My question now is what is the way around it to have a model with tunable Magnetization resistance and inductance [Rm(pu) Lm(pu)]. Is there any way ?. If not, what is your recommendation ?

Can the following like work in case ? https://comp.soft-sys.matlab.narkive.com/Lj55e2UO/how-to-programmatically-set-a-tunable-parameter .

[Walter Roberson]

I do not know if there is a work-around. I think it would be worth experimenting with making the value a global variable as is discussed in the link, but I do not know if it will work.