Newbee fault. I created an input item (knob) with min 0 and max 3 - that works fine. maybe this helps other newbees 
Items to enter data - Development / Add-ons - openHAB Community
Newbee fault. I created an input item (knob) with min 0 and max 3 - that works fine. maybe this helps other newbees Items to enter data - Development / Add-ons - openHAB Community