Troubleshoot Parameters Not Accessible by Name
Some parameters cannot be observed or tuned in the real-time application.
What This Issue Means
Reasons that you cannot observe or tune some parameters in the real-time application are:
- Simulink® Real-Time™ does not support parameters of multiword data types. 
- During execution, you cannot tune parameters that change the model structure, for example, by adding a port. To change these parameters, you must stop the execution, change the parameter, and rebuild the real-time application. 
Try This Workaround
Check the parameters for the issues described in What This Issue Means.