The pilot column contains a large number of different sensors. It is equipped with five Coriolis mass flow meters for the feed stream and the four product streams. At every 25 cm along the full height of each column section, as well as in the Y-pieces and in the heating jackets of the column sections, there are Pt100 sensors for temperature measurement. The current set-up does not allow a direct measurement of the product stream temperatures. As a remedy, the temperature sensors closest to the respective product streams are used to monitor the temperatures of the product streams. In Fig. the approximate location of the sensors used for monitoring the product temperatures is depicted. The temperature of the vapor entering the condenser represents the top temperature TD, while temperature sensors in the respective column sections around 15 cm above the side draws represent the temperatures TS1 and TS2 of the side products S1 and S2. The temperature inside the reboiler represents the bottom temperature TB. With the help of a radar level sensor, the liquid level inside the reboiler can be determined. All the measured quantities, including the above-mentioned mass flows, are available in the process control system of the column.