The new Control 4000 is a powerful, microprocessor-based photometric converter. The advanced modular design enables precision process monitoring and control. The flexible C4000 is designed for optek ultraviolet (UV), visible (VIS), near-infrared (NIR) absorption-based and scattered-light based sensors. The menu-based software is easy to use and configure and is now available in Russian and Portuguese in addition to German, English, French, Dutch and Spanish. The new high contrast white display is easier to read and remains configurable. The graphic display can show absorbance, transmittance and concentration in real time, and in any unit of measure such as CU, ppm, EBC, FTU, and g/l. These measurements may also be displayed as text, bar graphs or trend values. The C4000 software includes adjustable signal damping, 16 linearization / calibration tables, and advanced calculation capabilities. As an additional feature for scattered light sensors a factory zero point has been implemented. A new secondary zero for additional offset as well as a slope adjustment have been added. This new manual adjustment can be used to compensate for long-term process related disturbances.