CN115290722A - Residual chlorine and pH data acquisition card adopting constant voltage method - Google Patents

Abstract

The invention relates to a residual chlorine and pH data acquisition card of a constant voltage method. A pH electrode interface is connected to a pH voltage conversion circuit, the pH voltage conversion circuit is connected to an ADC converter, and the ADC converter is respectively connected to a residual chlorine voltage acquisition circuit and a temperature voltage acquisition circuit. , Single-chip microcomputer, the single-chip microcomputer is connected to the RS485 communication circuit, the residual chlorine voltage acquisition circuit is connected to the residual chlorine electrode acquisition interface, and the temperature and voltage acquisition circuit is connected to the thermistor RT. The invention simultaneously detects residual chlorine and pH value, integrates residual chlorine and pH into a data acquisition card, reduces cost and improves economic benefit.

Description

A data acquisition card for residual chlorine and pH in constant voltage method

technical field

The invention relates to the technical field of water quality monitoring equipment, in particular to a method for simultaneously detecting residual chlorine and pH values, integrating residual chlorine and pH into one data acquisition card, reducing costs, and improving economic benefits by using a constant voltage method for collecting residual chlorine and pH data Card.

Background technique

pH electrode, also known as pH probe, pH sensor, English name pH electrode or pH sensor, is the part of the pH meter that is in contact with the substance to be measured, and is used to measure the electrode potential. There are usually two methods to measure the pH value in aqueous solution, colorimetric method (pH test paper and cuvette) and potentiometric method. The potentiometric method is the only method that can achieve continuous on-line measurement and process monitoring, and the potentiometric method can obtain accurate and repeatable pH values. The core theory of pH electrode measurement is the Nernst equation. Electrodes used in potentiometric analysis are called primary cells. A primary battery is a system whose function is to convert chemical reaction energy into electrical energy. The voltage of this battery is called electromotive force (EMF). This electromotive force (EMF) is formed by two half-cells. One of the half-cells is called the measuring electrode, and its potential is related to a specific ion activity; the other half-cell is the reference half-cell, usually called the reference electrode, which is generally connected to the measuring solution and connected to the measuring instrument . The most familiar and commonly used pH indicating electrode is the glass electrode. An industrial on-line pH measurement system usually consists of four parts: a pH sensor, namely a pH electrode, a pH transmitter, an electrode sheath, and a cable.

The residual chlorine electrode is an online residual chlorine sensor, which is matched with the corresponding residual chlorine detector to form an online residual chlorine monitoring system instrument. Residual chlorine electrode is also called residual chlorine sensor and residual chlorine probe. Diaphragm polarographic (clark) sensor consists of cathode, anode, electrolyte and a layer of gas-permeable film covered on the cathode. The residual chlorine in the measured solution diffuses to the cathode through the diaphragm, and the appropriate polarization voltage between the cathode and the anode can reduce the residual chlorine on the cathode. These chemical reactions generate a current proportional to the residual chlorine in the measured solution. The constant voltage sensor consists of two platinum electrodes and a reference electrode to form a micro-battery measurement system. During the measurement, a stable potential is maintained at the electrode measuring end, and different measured components produce different and linear current intensities under the potential.

The constant voltage method for residual chlorine monitors ClO ^- ions in CLO ₂ and HClO, in which H ⁺ ions are represented by pH value, which will affect the detection value of residual chlorine and cannot be ignored. When detecting residual chlorine, it is necessary to compensate the residual chlorine value according to different pH values. There is a need for a residual chlorine and pH data acquisition card of a constant voltage method that simultaneously detects residual chlorine and pH value, integrates residual chlorine and pH into a data acquisition card, reduces costs, and improves economic benefits.

Contents of the invention

The object of the present invention is to provide a residual chlorine and pH data acquisition card for the constant voltage method that simultaneously detects residual chlorine and pH value, integrates residual chlorine and pH into one data acquisition card, reduces cost, and improves economic benefits.

A residual chlorine and pH data acquisition card for constant voltage method, comprising:

pH electrode interface, the pH electrode interface is connected to a pH voltage conversion circuit, the pH voltage conversion circuit is connected to an ADC converter, and the ADC converter is respectively connected to a residual chlorine voltage acquisition circuit, a temperature and voltage acquisition circuit, and a single-chip microcomputer, and the single-chip microcomputer is connected to RS485 communication circuit, the residual chlorine voltage acquisition circuit is connected to the residual chlorine electrode acquisition interface, and the temperature and voltage acquisition circuit is connected to thermistor RT.

The pH electrode interface is connected to the resistor R1 of the pH voltage conversion circuit, one path of the resistor R1 is connected to the capacitor C1 and then grounded, and the other path is connected to the third interface of the amplifier U1, and the second interface of the amplifier U1 is respectively connected to the first port of the amplifier U1. interface, resistor R2, the resistor R2 is respectively connected to the resistor R3, the capacitor C2, and the third interface of the amplifier U2, the resistor R3 is connected to the VREF interface, the capacitor C2 is grounded, and the second interface of the amplifier U2 is respectively connected to the amplifier U2 The first interface of the first interface and the resistor R4, the resistor R4 is respectively connected to the capacitor C3 and the first interface of the ADC converter, and the capacitor C3 is grounded.

The WE interface of the residual chlorine electrode acquisition interface is connected to the inductance L1 of the residual chlorine voltage acquisition circuit, and the inductance L1 is connected in parallel with the capacitor C4, the resistor R5, the second interface and the first interface of the amplifier U3, and then connects the resistor R7, and the amplifier The third interface of U3 is connected to the resistor R9 and grounded, the resistor R7 is connected in parallel with the capacitor C5, the resistor R6, the second interface and the first interface of the amplifier U4, and then connected to the resistor R8, and the third interface of the amplifier U4 is connected to the DAC1 interface, The resistor R8 is respectively connected to the capacitor C6 and the second interface of the ADC converter, and the capacitor C6 is grounded;

The RE interface of the residual chlorine electrode acquisition interface is connected to the inductance L2 of the residual chlorine voltage acquisition circuit, the inductance L2 is connected to the resistor R10, the resistor R10 is connected in parallel with the capacitor C7, the capacitor C10, the resistor R12 and the amplifier U8, the amplifier U8 The second interface is connected to resistor R12, the first interface of the amplifier U8 is connected to resistor R13, the third interface of the amplifier U8 is connected to resistor R14, and the resistor R14 is respectively connected to the resistor R11 and the first interface of the amplifier U9. R11 is respectively connected to the second interface of the amplifier U9 and the DAC0 interface, and the third interface of the amplifier U9 is grounded.

One end of the thermistor RT is grounded, and the other end is respectively connected to the resistor R15 of the temperature and voltage acquisition circuit, the capacitor C8, and the third interface of the amplifier U10, the resistor R15 is connected to the VREF interface, the capacitor C8 is grounded, and the amplifier U10 The second interface is respectively connected to the first interface of the amplifier U10 and the resistor R17, and the resistor is respectively connected to the capacitor C9 and the third interface of the ADC converter, and the capacitor C9 is grounded.

The 4th interface of the ADC converter is connected to the single-chip microcomputer, the TX interface of the single-chip microcomputer is connected to the first interface of the RS485 communication U7 of the RS485 communication circuit, and the EX interface of the single-chip microcomputer is respectively connected to the second interface and the third interface of the RS485 communication U7 , the RX interface of the single-chip microcomputer is connected to the 4th interface of the RS485 communication U7, and the 6th and 7th interfaces of the RS485 communication U7 are respectively connected to the 2nd interface of the interface CN2 and the 1st interface of the interface CN2.

The VREF interface is a supply voltage interface.

The DAC0 interface of the residual chlorine voltage acquisition circuit is a drive voltage interface, and the DAC1 interface of the residual chlorine voltage acquisition circuit is a boost voltage interface.

The pH electrode interface of the present invention is connected to the pH voltage conversion circuit, the pH voltage conversion circuit is connected to the ADC converter, and the ADC converter is respectively connected to the residual chlorine voltage acquisition circuit, the temperature and voltage acquisition circuit, and the single-chip microcomputer, the single-chip microcomputer is connected to the RS485 communication circuit, and the residual chlorine voltage acquisition circuit is connected to the The residual chlorine electrode acquisition interface, the temperature and voltage acquisition circuit is connected to the thermistor RT. The invention detects residual chlorine and pH value at the same time, integrates residual chlorine and pH into one data acquisition card, reduces cost and improves economic benefit.

Description of drawings

Fig. 1 is a block diagram of the present invention;

Fig. 2 is a circuit diagram of the present invention;

Fig. 3 is the circuit diagram of pH voltage conversion circuit of the present invention;

Fig. 4 is the circuit diagram of residual chlorine voltage acquisition circuit of the present invention;

Fig. 5 is the circuit diagram of temperature and voltage acquisition circuit of the present invention;

Fig. 6 is the circuit diagram of ADC converter, single-chip microcomputer, RS485 communication circuit of the present invention;

In the figure: 1. pH electrode interface, 2. pH voltage conversion circuit, 3. Residual chlorine electrode acquisition interface, 4. Residual chlorine voltage acquisition circuit, 5. Thermistor RT, 6. Temperature and voltage acquisition circuit, 7. ADC conversion device, 8, single-chip microcomputer, 9, RS485 communication circuit.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

A residual chlorine and pH data acquisition card for a constant voltage method, comprising: a pH electrode interface, the pH electrode interface is connected to a pH voltage conversion circuit, the pH voltage conversion circuit 2 is connected to an ADC converter 7, and the ADC converter 7 is respectively connected to residual chlorine voltage acquisition Circuit 4, temperature and voltage acquisition circuit 6, single-chip microcomputer 8, single-chip microcomputer 8 is connected to RS485 communication circuit 9, residual chlorine voltage acquisition circuit 4 is connected to residual chlorine electrode acquisition interface 3, temperature and voltage acquisition circuit 6 is connected to thermistor RT5.

The pH electrode interface 1 is connected to the resistor R1 of the pH voltage conversion circuit 2. One path of the resistor R1 is connected to the capacitor C1 and grounded, and the other path is connected to the third interface of the amplifier U1. The second interface of the amplifier U1 is respectively connected to the first interface of the amplifier U1 and the resistor R2. , the resistor R2 is respectively connected to the resistor R3, the capacitor C2, and the third interface of the amplifier U2, the resistor R3 is connected to the VREF interface, the capacitor C2 is grounded, the second interface of the amplifier U2 is respectively connected to the first interface of the amplifier U2, the resistor R4, and the resistor R4 is respectively connected to The capacitor C3 is the first interface of the ADC converter 7, and the capacitor C3 is grounded.

The WE interface of the residual chlorine electrode acquisition interface 3 is connected to the inductance L1 of the residual chlorine voltage acquisition circuit 4, the inductance L1 is connected in parallel with the capacitor C4, the resistor R5, the second interface and the first interface of the amplifier U3, and then connected to the resistor R7, the third interface of the amplifier U3 The interface is connected to resistor R9 and grounded, resistor R7 is connected in parallel with capacitor C5, resistor R6, the second interface and the first interface of amplifier U4, and then resistor R8 is connected, the third interface of amplifier U4 is connected to DAC1 interface, and resistor R8 is respectively connected to capacitor C6 and ADC The second interface of the converter 7, the capacitor C6 is grounded; the RE interface of the residual chlorine electrode acquisition interface 3 is connected to the inductance L2 of the residual chlorine voltage acquisition circuit 4, the inductance L2 is connected to the resistor R10, and the resistor R10 is connected in parallel with the capacitor C7, capacitor C10, resistor R12 and Amplifier U8, the second interface of amplifier U8 is connected to resistor R12, the first interface of amplifier U8 is connected to resistor R13, the third interface of amplifier U8 is connected to resistor R14, resistor R14 is respectively connected to resistor R11, the first interface of amplifier U9, and resistor R11 is respectively Connect the 2nd interface of the amplifier U9 and the DAC0 interface, and the 3rd interface of the amplifier U9 is grounded.

One end of the thermistor RT5 is grounded, and the other end is respectively connected to the resistor R15 of the temperature and voltage acquisition circuit 6, the capacitor C8, and the third interface of the amplifier U10, the resistor R15 is connected to the VREF interface, the capacitor C8 is grounded, and the second interface of the amplifier U10 is respectively connected to the amplifier U10 The first interface of the resistor R17 is connected to the capacitor C9 and the third interface of the ADC converter 7 respectively, and the capacitor C9 is grounded.

The 4th interface of the ADC converter 7 is connected to the single-chip microcomputer 8, the TX interface of the single-chip microcomputer 8 is connected to the first interface of the RS485 communication U7 of the RS485 communication circuit 9, and the EX interface of the single-chip microcomputer 8 is respectively connected to the second interface and the third interface of the RS485 communication U7, The RX interface of the microcontroller 8 is connected to the fourth interface of the RS485 communication U7, and the sixth and seventh interfaces of the RS485 communication U7 are respectively connected to the second interface of the interface CN2 and the first interface of the interface CN2.

The VREF interface is the supply voltage interface. The DAC0 interface of the residual chlorine voltage acquisition circuit 4 is a drive voltage interface, and the DAC1 interface of the residual chlorine voltage acquisition circuit 4 is a boost voltage interface.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments, and that described in the above-mentioned embodiments and the description only illustrates the principles of the present invention, and the present invention also has various aspects without departing from the spirit and scope of the present invention. Variations and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (7)

1. a residual chlorine and pH data acquisition card of constant voltage method, is characterized in that, comprises: The pH electrode interface (1), the pH electrode interface (1) is connected to the pH voltage conversion circuit (2), the pH voltage conversion circuit (2) is connected to the ADC converter (7), and the ADC converter (7) is respectively Connect residual chlorine voltage acquisition circuit (4), temperature and voltage acquisition circuit (6), single-chip microcomputer (8), described single-chip microcomputer (8) connects RS485 communication circuit (9), described residual chlorine voltage acquisition circuit (4) connects residual chlorine An electrode acquisition interface (3), and the temperature and voltage acquisition circuit (6) is connected to a thermistor RT (5). 2. the residual chlorine of a kind of constant voltage method according to claim 1 and pH data acquisition card, it is characterized in that, described pH electrode interface (1) connects the resistance R1 of pH voltage conversion circuit (2), and described resistance One path of R1 is connected to the capacitor C1 and grounded, and the other path is connected to the third interface of the amplifier U1. The second interface of the amplifier U1 is respectively connected to the first interface of the amplifier U1 and the resistor R2. The resistor R2 is respectively connected to the resistor R3, the capacitor C2, The third interface of the amplifier U2, the resistor R3 is connected to the VREF interface, the capacitor C2 is grounded, the second interface of the amplifier U2 is respectively connected to the first interface of the amplifier U2, and the resistor R4, and the resistor R4 is respectively connected to the capacitor C3, The first interface of the ADC converter (7), the capacitor C3 is grounded. 3. the residual chlorine of a kind of constant voltage method according to claim 1 and pH data acquisition card, it is characterized in that, the WE interface of described residual chlorine electrode acquisition interface (3) connects residual chlorine voltage acquisition circuit (4) An inductance L1, the inductance L1 is connected in parallel with the capacitor C4, the resistor R5, the second interface and the first interface of the amplifier U3, and then the resistor R7 is connected, the third interface of the amplifier U3 is connected to the resistor R9 and grounded, and the resistor R7 is connected in parallel with the capacitor C5, resistor R6, the second interface and the first interface of the amplifier U4, then connect the resistor R8, the third interface of the amplifier U4 is connected to the DAC1 interface, and the resistor R8 is respectively connected to the first capacitor C6 and the ADC converter (7) 2 interface, the capacitor C6 is grounded; The RE interface of the residual chlorine electrode acquisition interface (3) is connected to the inductance L2 of the residual chlorine voltage acquisition circuit (4), and the inductance L2 is connected to a resistor R10, and the resistor R10 is connected in parallel with a capacitor C7, a capacitor C10, a resistor R12 and an amplifier U8 , the second interface of the amplifier U8 is connected to the resistor R12, the first interface of the amplifier U8 is connected to the resistor R13, the third interface of the amplifier U8 is connected to the resistor R14, and the resistor R14 is respectively connected to the resistor R11 and the first port of the amplifier U9. 1 interface, the resistor R11 is respectively connected to the second interface of the amplifier U9 and the DAC0 interface, and the third interface of the amplifier U9 is grounded. 4. the residual chlorine of a kind of constant voltage method according to claim 1 and pH data acquisition card, it is characterized in that, one end of said thermistor RT (5) is grounded, and the other end is respectively connected to temperature and voltage acquisition circuit (6) The resistor R15, the capacitor C8, and the third interface of the amplifier U10, the resistor R15 is connected to the VREF interface, the capacitor C8 is grounded, the second interface of the amplifier U10 is respectively connected to the first interface of the amplifier U10, the resistor R17, and the resistors are respectively The capacitor C9 is connected to the third interface of the ADC converter (7), and the capacitor C9 is grounded. 5. the residual chlorine of a kind of constant voltage method according to claim 1 and pH data acquisition card, it is characterized in that, the 4th interface of described ADC converter (7) connects single-chip microcomputer (8), and described single-chip microcomputer (8) ) of the TX interface connects the first interface of the RS485 communication U7 of the RS485 communication circuit (9), and the EX interface of the single-chip microcomputer (8) connects the second interface and the third interface of the RS485 communication U7 respectively, and the single-chip microcomputer (8) The RX interface is connected to the fourth interface of the RS485 communication U7, and the sixth and seventh interfaces of the RS485 communication U7 are respectively connected to the second interface of the interface CN2 and the first interface of the interface CN2. 6. The residual chlorine and pH data acquisition card of a kind of constant voltage method according to claim 1, characterized in that, the VREF interface is a power supply voltage interface. 7. the residual chlorine of a kind of constant voltage method according to claim 1 and pH data acquisition card, it is characterized in that, the DAC0 interface of described residual chlorine voltage acquisition circuit (4) is a driving voltage interface, and described residual chlorine voltage The DAC1 interface of the acquisition circuit (4) is a boosted voltage interface.

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