eutech-instruments dissolved oxygen probe 用户手册
2 INSTALLATION
The Eutech probe is easy to install. It should be placed where there is some
movement in the water-1 cm/sec is enough at 7 mg/1 and 13 C. Ensure that the
probe does not strike against the tank wall, and do not mount it directly above
diffusers etc.
Each probe is connected using ordinary 2-core cable, and it is fitted with 3
meters of PU cable unless otherwise specified. The brown wire is positive, the
blue negative.
movement in the water-1 cm/sec is enough at 7 mg/1 and 13 C. Ensure that the
probe does not strike against the tank wall, and do not mount it directly above
diffusers etc.
Each probe is connected using ordinary 2-core cable, and it is fitted with 3
meters of PU cable unless otherwise specified. The brown wire is positive, the
blue negative.
3 DIRECTIONS FOR USE
3.1 Calibration
Calibration is carried out by placing the probe in air or air saturated water,
waiting for temperature equalization then adjusting the transmitter or electronics
connected so that the output corresponds to the calibration value. If you are
measuring % saturation on the calibration value is always 100%. If you are
measuring mg/l (ppm) temperature, the barometric pressure and the water
salinity all affect the calibration value.
The probe must have the same temperature as the water or air surrounding it, and
must therefore be allowed to attain this temperature before being calibrated. Any
robust long-life probe such as the Eutech can take up to an hour to respond to a
10-degree temperature change in air, which only takes 10 minutes in water. This
must be taken into account when calibrating.
Take the probe up from the water, wipe the membrane dry, and hang it in free
air, away from direct sunlight. When the probe output is stable adjust the
transmitter or electronics connected to give the correct output.
Calibration value for systems measuring % saturation
The calibration value for systems measuring % saturation is always 100. For
these systems, and only for these systems, temperature, barometric pressure and
salinity have no influence.
Calibration value for systems measuring mg/l (ppm)
For these measurements adjustment until the output corresponds to the
appropriate value from the calibration tables. Temperature, pressure and salinity
affect the value. The first table at the end of this section shows values for various
temperature and air pressures, the other values for various temperatures and
salinity at 760 mbar.
It is essential to correct for temperature-use the air temperature near the probe.
At high altitudes, or for greater accuracy, a correction must be made for pressure.
The salinity should be corrected for in salt-water measurements. For a simple
calibration at low altitudes assume a normal barometric pressure of 760 mmHg.
How often should calibration be performed?
Unfortunately, it is not possible to answer this question. A new probe needs more
frequent calibration than an “old”. Calibration frequently also depends on the
accuracy desired. If an accuracy of +/- 0.5 ppm is sufficient, calibration once a
month is more than enough. It is, however, much better to perform one thorough
calibration than two quick ones. Give the probe time to stabilize, check the
barometer and decide if correction for air pressure is necessary. Check the
salinity if your farm is a salt-water facility!
waiting for temperature equalization then adjusting the transmitter or electronics
connected so that the output corresponds to the calibration value. If you are
measuring % saturation on the calibration value is always 100%. If you are
measuring mg/l (ppm) temperature, the barometric pressure and the water
salinity all affect the calibration value.
The probe must have the same temperature as the water or air surrounding it, and
must therefore be allowed to attain this temperature before being calibrated. Any
robust long-life probe such as the Eutech can take up to an hour to respond to a
10-degree temperature change in air, which only takes 10 minutes in water. This
must be taken into account when calibrating.
Take the probe up from the water, wipe the membrane dry, and hang it in free
air, away from direct sunlight. When the probe output is stable adjust the
transmitter or electronics connected to give the correct output.
Calibration value for systems measuring % saturation
The calibration value for systems measuring % saturation is always 100. For
these systems, and only for these systems, temperature, barometric pressure and
salinity have no influence.
Calibration value for systems measuring mg/l (ppm)
For these measurements adjustment until the output corresponds to the
appropriate value from the calibration tables. Temperature, pressure and salinity
affect the value. The first table at the end of this section shows values for various
temperature and air pressures, the other values for various temperatures and
salinity at 760 mbar.
It is essential to correct for temperature-use the air temperature near the probe.
At high altitudes, or for greater accuracy, a correction must be made for pressure.
The salinity should be corrected for in salt-water measurements. For a simple
calibration at low altitudes assume a normal barometric pressure of 760 mmHg.
How often should calibration be performed?
Unfortunately, it is not possible to answer this question. A new probe needs more
frequent calibration than an “old”. Calibration frequently also depends on the
accuracy desired. If an accuracy of +/- 0.5 ppm is sufficient, calibration once a
month is more than enough. It is, however, much better to perform one thorough
calibration than two quick ones. Give the probe time to stabilize, check the
barometer and decide if correction for air pressure is necessary. Check the
salinity if your farm is a salt-water facility!
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