Description
TDS Sensor Module Dissolved Solids Detect Analog Signal Water Quality Sensor DS18B20 Solubility Test Kit for 51 STM32
Products Description
1, PRODUCTION
TDS (Total Disolved Solids), the Chinese name total dissolved solids, also known as the total amount of dissolved solids, indicating how many milligrams of dissolved solids are dissolved in 1 liter of water. In general, the higher the TDS value, the more lysate is contained in the water and the more unclean the water. Although TDS does not effectively reflect the water quality under certain circumstances, as a parameter that can be quickly detected, TDS can still be used as a reference for effective water quality reflection parameters. The commonly used TDS testing equipment is a TDS pen. Although it is inexpensive and easy to use, it cannot transmit data to the control system, do long-term online monitoring, and analyze the water quality. Using a special instrument, although the data can be transmitted, the accuracy is high, but the price is very expensive. To this end, we have specifically introduced this TDS sensor module. The module is plug and play, easy to use. The wide voltage supply of 3.3~5.5V and the analog signal output of 0~2.3V make this product compatible with 5V, 3.3V control system, which can be easily used in the ready-made control system. The excitation source used for measurement uses an AC signal, which can effectively prevent probe polarization, extend probe life, and increase the stability of the output signal. The TDS probe is a waterproof probe that can be immersed in water for long periods of time. The product can be applied to water quality testing in the fields of domestic water, hydroponics and the like. With this sensor, you can easily DIY a TDS detector, and easily check the cleanliness of the water to make your water quality better.
2, Module introduction and PIN DEFINITION
The module is connected to the TDS probe through a 2Pin XH-2.54 connector, and the DS18B20 temperature sensor interface is extended to facilitate software temperature compensation design.
VCC : supply voltage positive : 5V or 3.3V GND： supply voltage negative T1: Temperature sensor DS18B20 signal output port: Temperature compensation by software AO: analog signal output:output voltage range 0 ~ 2.3V + Temperature sensor power supply positive T: temperature sensor signal line - : Temperature sensor power supply negative 1:TDS probe lead 1 2 : TDS probe lead 2
Product Paramenters
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3, Technical indicators
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Supply voltage
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3.3~5.0V
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Output signal range
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0~2.3V
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Working current
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3~6mA TDS
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Measuring range
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0~1000ppm
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TDS measurement accuracy
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5% F.S. (25 ° C)
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Module size
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42mm × 31.2mm
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TDS probe interface
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2Pin XH-2.54
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Temperature sensor interface
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3Pin XH-2.54
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Features: (1) Wide voltage operation: 3.3~5.5V (2) 0~2.3V analog signal output, compatible with 5V, 3.3V two control systems (1) excitation source is AC signal, effectively prevent probe polarization (2) waterproof probe, can be immersed in water for a long time
4, TDS probe DESCRIPTION
The specific parameters of the TDS probe are shown in the table below. (Applicable to 2 points PE pipe)
Insulation resistance between two poles: ≥ 50MΩ (when not in contact with water) Detecting medium temperature:≤ 70 ° C Recommended operating voltage: ≤ 5.0V (refers to the voltage sandwiched between the two probes) Recommended operating current: ≤ 50uA (the smaller the current, the longer the probe life) Line length: 58CM
Installation Instructions
5, Instructions
(1) Sensor installation The probe is fitted with 702 tee, and the installation method is as shown in the figure below. (2) Standard curve and temperature calibration formula The common unit of TDS is ppm (parts per million), which is expressed as the concentration of solute mass in parts per million of the mass of the solution, also known as the parts per million. TDS sensor module standard curve as shown below
The temperature correction coefficient T is calculated as follows: T=1+0.02×(T-25) Where T is the temperature correction coefficient and T is the measured temperature of the solution to be tested. Note: (1) The unit of measurement of TDS is sometimes expressed in mg/L, and the conversion relationship with ppm is 1 mg/L = 1 ppm; (2) There is often a similar relationship between TDS and conductivity. Sometimes TDS can also be used to indicate conductivity. The relationship between the two is 1 ppm = 2 uS/cm, where uS/cm is the unit of conductivity. (3) National Standard GB5749-2006 "Standards for Drinking Water Hygiene" specifies the limited amount of TDS for drinking tap water: total dissolved solids ≤ 1000ppm (three) calibration method Due to individual differences in TDS probes or temperature compensation, there is a large error in the measured values. Therefore, in order to obtain a more accurate TDS value, calibration must be performed before measurement. In addition, it is recommended to connect the temperature sensor for temperature compensation to improve measurement accuracy. The specific operation method is described below.
Step 1: connecting the TDS probe to the temperature sensor;
Step 2: Record the standard TDS solution or measure the TDS value of the solution to be tested with a TDS pen and record it as the TDS standard value. The third step: powering the TDS sensor module, putting the TDS probe and the temperature sensor into the TDS standard solution or the solution to be tested with the known TDS value, and testing the output voltage value of the sensor module AO port, and recording it as a V test. The current test solution is measured as a value recorded as a Ta test. The measured voltage value V test and the T test are substituted into the TDS standard curve formula and the temperature correction coefficient calculation formula. T=1+0.02×(T test one 25) V (correction) = T (correction) × V test (test) TDS test value = (66.71 × V with positive 3-127.93 × V (corrected) square + 428.7 × V (corrected)) Step 4: Calculate the K value. Assuming a TDS standard value = 90 ppm; a TDS measurement value = 100 ppm, the calculation can yield a K value of 0.9. K=TDS standard value/TDS measurement value Step 5: Correct the K value. The calculated K value is corrected in the program. Correct the kValue value equal to the calculated K value. Float kValue=0.9; The results of the calibration test after calibration are shown in the figure below.
6, matters needing attention
1. TDS probes cannot be used in water above 55 °C. 2. The TDS probe should not be placed too close to the edge of the container, otherwise it will affect the display. 3, TDS probe head and wire are waterproof, can be immersed in water, but the connection interface and signal adapter plate are not waterproof, please pay attention to use.