Are you sure you are using the 220 code correctly?
Turn key to PGM2 mode
220
.
X
PLU number (you must type it on the numeric keys)
X
2
Now the 2 digit department to link to e.g 01
SUBTOTAL (ST)
Total (TL or CASH)
If anyone needs a Sharp ER-3110 manual, see here:
http://the-checkout-tech.com/manuals/cashregisters/Sharp3.php
Registerman
August 2010