Calibration; General Information; Single Point Calibration - Lovibond Tintometer SD 400 Oxi L Manual De Instrucciones

8 Calibration

8.1 General information

If no saturated air is available for a single-point calibration, the storage flask can be used to
obtain 100 % water-saturated air. 1-point calibration in 100 % water-saturated air is recom-
mended according to DIN ISO 17289, see 2. under 8.2.
The dissolved oxygen concentration is dependent on the temperature (T), the pressure (BP)
and the salt content (S).
T means automatic temperature compensation (ATC); NO means that no temperature com-
pensation is performed.
BP means that the automatic pressure compensation is performed; NO means that no pres-
sure compensation is performed.
S means salinity and is defined as NaCl, Mg-sulphate and Ca-sulphate, etc., dissolved in water.
The salt concentration can be determined based on the conductivity. In order to be able to
consider the salt compensation in the measurement of the oxygen, the salt concentration is
entered in ppt (parts per thousand) or in mS/cm (see 7.3 "Salinity correction"). The oxygen
concentration is specified in consideration of the manually entered salt concentration as
saturation in %.
8.2 Single-point calibration
There are two possibilities for performing a single-point calibration:
1. Calibration in air-saturated water:
The water is continuously flushed with air by blowing the water with a fan until complete
saturation for a period of approximately 10 minutes.
The sensor is held in the air-saturated water until both the temperature and the oxygen display
(mg/l or Sat%) have reached a stable value.
If no air-saturated is available for a single-point calibration, the storage flask can be used to
obtain 100 % water-saturated air (see point 2).
2. Calibration in water-saturated air (recommended according to DIN ISO 17289):
The sensor is exposed to the air with a relative air humidity of 100 %. For this purpose, the
storage sleeve with water-soaked sponge is screwed on the sensor and a waiting period of
at least 15 minutes is observed until the measurement value has stabilised.
15 min
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SD_400 Oxi L_4 07/2020