# “Hidden” variable in Simulink models

Some example models that are included in the Simulink library, there are some variables that their value is not visible. For instance, in the model power_PVarray_grid_det the sample time of the powergui is defined as Ts_Power. I can not figure out the value of this variable. Is there a way to find these hidden variables, have access to them and change their value?

1. Click the File/Model Properties/Model Properties item in the model window menu
2. Select the Callbacks tab in the model properties dialog window
Then you can see that the PreLoadFcn callback is defined as follows:
This code is executed before the model is loaded, so Ts_Power is initialized to 10^-6.