The critical angle refractometer ATR-P is especially designed for applications in the sugar industry. Complete system consists of the ATR-P measuring head and the “L-Controller” electronic unit. As an alternative to the “L-Controller” electronic unit, the ATR-P measuring head can be connected to a PC or laptop. In the minimal version configuration and calibration are performed using a supplied free software. Much more comfortable version is the PC software “Aquisys Basic”.