UR242 and standalone mode?

Hi all,
I’m planning to buy a UR242 in order to replace both my Yamaha mixer and my old M-audio delta 2496 audio interface.
If I plug my digital piano (inputs 3-4), can I have sound in the output with the ​computer off ?

I would like to use the interface as a mixer and play my piano without necessarily having to switch on my computer.