Memosens CCS50D provides stable, fast measured values so processors can be sure water treatment remains within limit values for disinfectants such as chlorine and chlorine dioxide. The sensor has a convex membrane that prevents soiling and resists biofouling. The membrane is ultrasonically welded to the sensor cap to prevent dilution of the electrolyte. During ongoing operation, plant operators can precalibrate sensors in the laboratory and swap them into the process with plug-and-play. Contactless data transmission eliminates measurement errors as well as failures caused by humidity or corrosion.