Datasheet

Turn off Console Blanking

You may notice the console goes black after 30 minutes, this is a sort of 'power saving' or 'screensaver' feature.

Raspbian Jessie

Add the following line to /etc/rc.local

sudo sh -c "TERM=linux setterm -blank 0 >/dev/tty0"

on the line before the final exit 0

Raspbian Wheezy

You can disable this by editing /etc/kbd/config and looking for

BLANK_TIME=30