Product introduction:
Conductivity is the ability of a solution to conduct current expressed in numbers, and the unit is expressed in Siemens per meter (S/m). In the formula, the conductivity is represented by the Greek letter r, which is the reciprocal of the resistivity p, namely K=%. In liquids, conductance, which is the reciprocal of resistance, is often used to measure its conductivity. The conductivity of water is a very important indicator of water quality, it can reflect the concentration of electrolytes in the water. Depending on the concentration of the electrolyte in the aqueous solution, the degree of conductivity of the solution is also different. Professional conductivity test equipment is expensive, and there is no secondary development interface and data. For this reason, we developed this low-cost and easy-to-use conductivity sensor module. This module has the characteristics of simple connection, convenience and practicality. It can be used to assess water quality, hydroponics, aquaculture, environmental water testing and other fields.
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Product parameters:
Supply voltage: 5.00V
Analog signal output voltage: 0~3.4V
Measurement accuracy: ±5%F.S.
Electrode interface: BNC
Temperature sensor interface: XH 2.54
Board size: 42mm*32mm
Conductivity electrode:
Electrode type: laboratory grade electrode, DJS-1
Conductivity cell constant: 1.0
Support measurement range: 0 20mS/cm
Recommended measurement range: 1~1 5mS/cm
Measuring temperature: 0-40℃
Electrode life: >0.5 years (the actual life is related to the frequency of use and the scene)
Cable length: 100cm
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Pin description:
VCC: Input voltage +
GND: Input voltage-
T1: Temperature sensor data output port
A0: Analog output port
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Instructions for use:
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1. Calibration method
To ensure accuracy, the electrode used for the first time or the electrode used for a period of time needs to be calibrated. The 2-point calibration method requires the use of conductivity standards of 1413uS/cm and 12.88mS/cm. The following will explain in detail how to perform 2-point calibration. The specific steps are as follows:
The first step: connect the conductivity sensor module and the conductivity electrode;
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Step 2: Calibration of the first point. Supply power to the conductivity sensor module. Put the conductivity electrode into a standard solution with a conductivity value of 1413us/cm, and test the output voltage of the AO port of the sensor calibration block. Record it as a V test. Measure the value of the current test solution and record it as T test. Substitute the measured voltage values V test and T test into the following calculation formula.
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kValue_Low=164x1.413x(1.0+ 0.0185x(T test-25.0))/V test
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Step 3: the second point calibration. Supply power to the conductivity sensor module, and put the conductivity board into a standard solution with a cardiac lead value of 12.88ms/cm. Test the output voltage value of the AO port of the sensor block and record it as a V test. Measure the value of the current test solution and record it as T test. Substitute the measured voltage values V test and T test into the following calculation formula.
kValue_High=164x12.88x(1.0+ 0.0185x(T test-25.0))/V test
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Step 4: Correct the K value. The calculated kValue_High and kValue_Low values are corrected in the program.
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Step 5: Compile and program the modified program, and then conduct conductivity measurement normally.
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Note:
1. The power supply voltage of the conductivity module is as close as possible to +5.00V, the more accurate the voltage, the higher the accuracy!
2. In order to ensure the measurement accuracy, it is strongly recommended to add a temperature sensor to measure the temperature of the solution and realize automatic temperature compensation.
3. Before measuring another solution, be sure to clean the conductivity electrode and absorb the remaining water droplets with absorbent paper to prevent contamination of the solution. The electrode can be rinsed with distilled water.
4. The calibration interval is related to the frequency of use. Normally, calibration is sufficient once a month. If used frequently, it can be calibrated once a week. When calibrating, try to use fresh conductivity standards.
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