When I tried to change input device which fits to my audio interface, pd vanilla freezes and crashes... It works still fine in purr data but in vanilla, it goes freeze all the time...

@tarim Difficult to diagnose, but as it is an asio device you will need to match the Pd settings to the device.
Change the Pd settings..... not the Focusrite settings.
Open up your control panel for the focusrite and check you have the same sample rate and the same buffer.... 64, 128, 256 etc. Buffer is "block size" in Pd.
Then it should work .
Probably ticking the "use callbacks" box is a good idea.
When it is working try reducing the Delay (msec} to 5.... then 4..... then 3...... until it doesn't work any more and then go back to the last value that worked. That should give you the lowest latency.

If you have no luck at all and you are using windows then try Asio4All...... http://tippach.business.t-online.de/asio4all/ .... instead of the Focurite driver. It will allow you to use more than one device at a time as well.
David.