The TS7 Sensor (self cleaning) consists of a light source and a light detector (photo detector). Incident light is scattered by the particles in the sample, and the scattered light is measured by the detector. The amount of scattering depends on the amount of material in the sample, the wavelength of light used and the size and composition of the suspended particles. The Sensor uses a long life near infrared LED (880nm) and the 90° scattered light method in accordance with ISO 1027/EN 27027 to assure accurate turbidity values.

An automated mechanical wiper is available to remain surface clean and remove air bubbles of the optical window in order to maximize the accuracy and minimize the maintenance requirement.

Turbidity is expressed in nephology-metric units (NTU), which are based on the light-scattering properties of a standardized formazin polymer solution.