Here are two ways in which you can define a Simscape parameter with a range of values:
1. You may use a Simulink.Parameter object in your Simscape model to define a range of values. See the attached example for a simple Simscape model that defines a resistor value with min and max values as a Simulink.Parameter object. You may notice that if the value of the parameter is defined to be out of range, you get an error in the simulation.
2. You can modify existing blocks to create the desired functionality. For example, the link below illustrates an example of how a capacitor can be modified so that an error is thrown when the capacitance is out of a specified range.
www.mathworks.com/help/physmod/simscape/lang/electrical-component-ideal-capacitor.html