General Notes; General Description; Factory Calibration; Operating Principles - Aqualytic AL250T-IR Mode D'emploi

General notes

GB

General description

The AL250T IR is a portable turbidity meter, based on the requirements of ISO 7027 (Water
Quality – Determination of Turbidity). The instrument features auto ranging over the range
of 0.01 to 1100 NTU/FNU.
The turbidimeter is supplied in a case complete with accessories and spares. Calibration
Standards guarantee stability and reproducibility of the results. Always replace the cover on
the sample chamber to protect against dust.

Factory calibration

The turbidimeter AL250T IR is factory calibrated with Formazin Primary Standard and does not
require user calibration before use (see chapter "Menu options: User calibration").

Operating principles

The instrument measures turbidity in the range 0.01 to 1100 NTU/FTU featuring auto rang-
ing. The light source is an infrared LED (light emitting diode) with a wavelength of 860 nm.
The emitted light is reflected by turbidity in the sample. The scattered light will be detected
at an angle of 90° by a photodiode.
This principle is part of ISO 7027.
The international Reference Standard for turbidity is a Formazin solution. Results related to
these standards are indicated as FNU (Formazine Nephelometric Units).
34 AL250T IR_4 01/2016