In Conclusion, I could work in external mode, with my Arduino MEGA 2650 Made in China whith CH340 controller in Matlab R2017b, in effect we must to change Boud Rate, in may case worked using 153660 as well, the example code is:
For the follow example you must to have opened your Simulink Project, after that:
In Worspace windows :
For checking Boud Rate you can wrinte im promp
After that you can try to play your Clone Arduino Made in China in External Mode.
Thanks a lot