Simulink errors out when multiple definitions of the same variable are found in referenced data dictionaries

I have a top-level model which has two model references A and B. Both models have their own data dictionaries a.sldd and b.sldd. Both data dictionaries have a variable called "Speed_Limit" defined in them, but they have different values. When I compile the model, I get the following error.

The symbol 'Speed_Limit' has more than one definition, and there are inconsistencies:
Caused by:
- value=200 for Speed_Limit in a.sldd (Use this definition)
- value=100 for Speed_Limit in b.sldd (Use this definition)

How do I fix this error?

Answer 1

[MathWorks Support Team]

This is expected behavior as data dictionaries are used to define variables with global scope.

Consider one of the following workarounds:

(1) Move the variables to the model workspace of the individual models. This will eliminate the conflicts on the top-level model.

(2) Starting in R2022a, there is the possibility to disable "EnforceDataConsistency" for a top-level model, which then disables this error and leads to each model reference only using the variable as defined in their data dictionaries. This can be done programmatically using 

 >> set_param(bdroot,'EnforceDataConsistency','off');

From R2022b there is an additional interactive way of disabling this parameter using the "Enforce consistent data definitions across referenced models" check box in Model Properties > External Data.

However, there are limitations to this approach. When "EnforceDataConsistency" is disabled, the following won't work (as of R2023a):

•    Code Generation

•    Simulation in SIL and PIL mode

•    Simulation of a protected model

Verify the limitations for your release in the "Data Used by Model References" section at the following documentation: https://www.mathworks.com/help/releases/R2023a/simulink/ug/migrate-models-to-use-dictionary.html#bu0qxhf-1 (adjust the URL to match your release).