Water Quality Sensor Accuracy of temperature compensation
± 0.3 mg/L
Water Quality Sensor Calibration period
Six months
Water Quality Sensor Temperature range
(0 ~ 60) °C
Water Quality Sensor Protection level
IP68
Water Quality Sensor MTBF
≥1440h/Time
Water Quality Sensor Means of communication
RS485(Modbus RTU) , maximum baud rate 115200 bps
General Knowledge of Dissolved Oxygen
Tips:Measuring Dissolved Oxygen by the Colorimetric Method
There are two variations of dissolved oxygen analysis by the
colorimetric method. These are known as the indigo carmine method
and the rhodazine D method. Both variations use colorimetric
reagents that react and change color when reacted with oxygen in
the water. These interactions are based on the oxidation of the
reagent, and the extent of the color change is proportional to the
dissolved oxygen concentration. Measuring dissolved oxygen by a
colorimetric method can be done with a spectrophotometer,
colorimeter, or a simple comparator. Using a spectrophotometer or a
colorimeter produces more accurate results, while comparison
against a comparator such as a color wheel or color block is quick
and inexpensive. However, as the human eye is not objective, this
can result in some inaccuracy.
Indigo Carmine
According to the indigo carmine method, the deeper the blue, the
higher the dissolved oxygen concentration.
The indigo carmine method can be used for measuring dissolved
oxygen concentrations between 0.2 and 15 ppm (mg/L). This method
produces a blue color, the intensity of which is proportional to
the dissolved oxygen concentration. Ferric iron, ferrous iron,
nitrite, and sodium hydrosulfite can interfere with this method. In
addition, reagents should be kept out of bright light as prolonged
exposure can deteriorate the indigo carmine. However, this method
is not affected by temperature, salinity, or dissolved gases.
Low-range tests are time-dependent and should be analyzed within 30
seconds, while high-range tests require a two-minute processing
time.
Rhodazine D
When measuring dissolved oxygen, the rhodazine D method will
produce a rich rosy-pink color.
The rhodazine D method is used to determine very low dissolved
oxygen concentrations. Able to measure in the parts per billion
(ppb), rhodazine D reagents react with dissolved oxygen to form a
deep rose-colored solution. This colorimetric method is not
affected by salinity or dissolved gases such as sulfide that can be
present in the water sample. However, oxidizing agents such as
chlorine, ferric iron and cupric copper can interfere and cause
higher DO readings. Other causes of error are polysulfides,
hydroquinone/benzoquinone, and boron and hydrogen peroxide (if both
are present). In addition, sample color and turbidity can affect
the accuracy of the readings. This method is time-dependent, as the
analysis must be made within 30 seconds of mixing the reagent.
Xi'an Kacise Optronics Co.,Ltd. is a professional manufacturer
of measuring instruments , located in China xi’an City. Since
2008, Xi'an Kacise focused on the development and production of
pressure, level and flow measuring instruments .
We have been specializing in manufacturing pressure, level and flow measuring instruments and related products for 10 years. Based on experienced technical
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Xi'an Kacise is qualified with ISO 9001-2008, GJB 9001B-2009, CE,
intrinsic safety explosion-proof and isolated safety
explosion-proof certificates, etc. which ensure that our products
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Kacise sensors have already been exported to America, Spain,
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