Ok.
Found the Raspberry Pi SD....
It's running Arch Linux with Proview 5.3.1-1, I have build from source.
Uploaded with the standard Arduino IDE, with board = Mega2560, to the Controllino with the sketch from:
maba.dk/arduino.ino and baud rate 57600.
With stty setting boot script:
stty -F /dev/ttyACM0 10:0:8be:0:3:1c:7f:15:1:0:1:0:11:13:1a:0:12:f:17:16:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0
chmod 777 /dev/ttyACM0
But I don't know if this sketch is running on a newer version of Proview...
The Ai is, like Claes suggested, for Ai0 number 0
Good luck,
/Marc