Excel in a timer 

I would like to know if there is any way
to download an excel file all days at the same
time with a timer.
The problem is, when i'm building the timer's action
i can't download the file.

Download where?
You can have a timer schedule to run daily at a specific time and generate the excel file, the question is where do you want to put that file?
Timers run on the server side, asynchronously, you don't have a user session and a client to send the file to.