An infusion system comprises an infusion pump that comprises an input unit and a display unit. The input unit is adapted for adjusting a value of at least one parameter for controlling operation of the infusion pump and/or an infusion process, and the display unit displays the value of the at least one parameter. The input unit comprises at least one slide bar adapted to be touched by a user's finger and moved along its length to change the value of the parameter, wherein movement in a first direction increases the value of the parameter and in a reversed, second direction decreases the value. The slide bar is adapted so that the rate of change of the parameter value correlates with the speed of the finger movement and in an idle mode is decelerated in a similar way as under influence of an inertia load and/or a friction.