This is the demo file for video demo:
http://www.mathworks.com/videos/pid-controller-design-for-a-dc-motor-68881.html
and "Seth on Simulink" blog post "PID Control Made Easy":
http://blogs.mathworks.com/seth/2009/12/24/pid-control-made-easy/

The demo shows the PID Controller block in Simulink and PID Tuner in Simulink Control Design:
http://www.mathworks.com/products/simcontrol/

PID Controller is used to control a simple DC Motor modeled in Simulink.

To see how to tune the PID Controller, please see the video demo and/or read the blog post.

You can also visit the web page with resources for designing and tuning PID controllers:
http://www.mathworks.com/discovery/pid-control.html