How to give parameter variation in simulink ??

How to give parameter variation in simulink ?? I want to introduce variation of parameter in simulink, a particular parameter should vary within a range.

[pravin behera]

Actually i dont want to control the parameter variation, but instead introduce parameter variation, a particular parameter if there, i want a function that will vary it randomly and give all possible outputs within the specified bound.

Answer 1

[Murali Krishna]

You can set the upper and lower limits for a signal using the saturation block. The input signal outside of these limits saturates to one of the bounds