CN101266223A - Milk conductance dynamic on-line detection and milk volume metering system - Google Patents

Abstract

A dynamic on-line detection of milk conductance and milk volume measurement system, which consists of standard electrodes, approved electrodes, collection electrodes, measurement solenoid valves, measurement circuits, control circuits and a central processing unit; the standard electrodes, approval electrodes and collection electrodes are installed in the measuring cup Inside; the control circuit is composed of a standard waveform generation circuit and a metering solenoid valve control circuit. The metering solenoid valve control circuit consists of a drive circuit and a high-voltage isolation circuit. The electric signal in the milk is collected by the approval electrode and the collection electrode, respectively, and is approved by the standard base generation circuit, and then input through the filter shaping circuit, amplification circuit, high-voltage linear isolation circuit and A/D conversion circuit, and then output to the central processing unit for software processing. to the LCD screen or the upper PC database. The invention has the advantages that the system has high measurement precision, can effectively reduce the electric polarization phenomenon of milk quality, and has safety and stability.

Description

Milk conductance dynamic on-line detection and milk volume metering system

Technical field:

The invention relates to a dynamic on-line detection and milk volume measurement system of milk conductance.

Background technique:

In the process of transitioning from manual milking to automated intelligent milking, the most important thing is to prevent milk from sick cows from entering the warehouse. Therefore, in the first line of milk quality production - the milk hall, the online dynamic detection of fresh milk is very important. Especially important, it is directly related to the safety issue of milk used by the whole people. The conductance is a main reflection of the milk quality index. At present, the online dynamic detection environment of raw milk conductance is relatively harsh. The milk itself has high-voltage static electricity and external stray current sources. Generally, there are large disturbances or even shocks of varying degrees in the milk solution, accompanied by indefinite proportions of bubbles. Moreover, there are various electrochemical phenomena such as carbonization and polarization, which easily lead to contamination of the measuring electrode and thus affect the measurement. Simultaneously, also there is same problem to the online measurement of milk volume.

Invention content:

The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art, and provide a dynamic on-line detection of milk conductance and milk volume measurement system, which has high measurement accuracy and can effectively reduce the electric polarization of milk quality. It is safe and stable.

The technical solution of the present invention is: a dynamic on-line detection of milk conductance and milk volume measurement system, which is characterized in that it is composed of a power supply, a standard electrode, an approved electrode, a collection electrode, a metering solenoid valve, a measurement circuit, a control circuit and a central processing unit The standard electrode, the approved electrode and the collection electrode are installed in the measuring cup; the control circuit is composed of a standard waveform generation circuit and a metering solenoid valve control circuit, the input port of the standard waveform generation circuit is connected with the waveform modulation output end of the central processing unit, and receives its The waveform modulation signal sent out, the output port of the standard waveform generation circuit is connected to the standard electrode to make it generate a trapezoidal AC voltage drive signal; the metering solenoid valve control circuit is composed of a drive circuit and a high-voltage isolation circuit, and the solenoid valve drive output terminal of the central processing unit It is connected to the input port of the high-voltage isolation circuit, the output port of the high-voltage isolation circuit is connected to the input port of the drive circuit, and the output port of the drive circuit is connected to the metering solenoid valve; the measurement circuit consists of a standard base generation circuit, a filter shaping circuit, an amplifier circuit, and a high-voltage line The isolation circuit and the A/D conversion circuit are connected sequentially; the electric signal in the milk is collected by the approval electrode and the collection electrode respectively and the standard base generation circuit is approved, and then passed through the filter shaping circuit, the amplification circuit, the high-voltage linear isolation circuit and the A/D The conversion circuit is input into the central processing unit for software processing and then output to the LCD screen or the database of the upper PC.

The present invention can also adopt following technical measures:

The above-mentioned standard waveform generating circuit is composed of inverter U5B, photocoupler U7D, precise adjustable potentiometer R42 and operational amplifier U8A connected in sequence.

The above reference ground generating circuit is composed of precise adjustable potentiometer R43, operational amplifier U8B and several capacitors connected in sequence;

The above-mentioned A/D conversion circuit is two TLC0831 chips.

The drive circuit and high voltage isolation circuit in the metering solenoid valve control circuit are composed of photocoupler U7A, field effect transistor Q2, freewheeling diode D3 and filter capacitors C42, C34 and C35 connected in sequence.

The above-mentioned central processing unit adopts 8052 series chips.

The above-mentioned power supply adopts a high-isolation power supply system.

The present invention has following advantage and positive effect:

1. The measurement terminal voltage of this system is small and stable, which provides a relatively complete platform for high-precision measurement. The terminal voltage is driven by a trapezoidal AC wave, which effectively reduces problems such as the electric polarization of milk quality.

2. The system adopts the differential measurement method, and successfully obtains stable sampling points. The method can effectively improve the accuracy and stability of online detection. It effectively solves the disturbance problem caused by foam and impact on the measurement, and has strong anti-disturbance ability.

3. The combination of software and hardware of the system has intelligent self-checking function, and dynamically obtains sampling points, which greatly improves the ability to investigate errors, and can perform online testing on its own hardware system for easy maintenance.

4. A high isolation scheme is adopted between the system network, the computing control system and the power supply system, which greatly improves the independence of the main control system and its own measurement network, effectively isolates external stray power sources and high-voltage static electricity, and thus ensures the safety of the entire system and stability are favorably guaranteed.

5. Software intelligent temperature compensation (compensation range: 5 ~ 60 degrees).

6. The system network is powered by a single low-voltage power supply, which effectively simplifies the circuit and its power supply system.

Description of drawings:

Fig. 1 is a schematic diagram of electrode installation of the present invention.

Fig. 2 is a functional block diagram of the present invention.

Fig. 3 is a schematic diagram of the measurement and control circuit of the present invention.

Fig. 4 is a schematic diagram of the drive circuit and the high-voltage isolation circuit in the control circuit of the metering solenoid valve.

Fig. 5 is a schematic diagram of the power supply in the present invention.

Detailed ways:

As shown in Figures 1 and 2: a dynamic on-line detection of milk conductance and milk volume measurement system, which consists of standard electrode P2, approved electrode P1, collection electrode P3, metering solenoid valve, measurement circuit, control circuit and central processing unit 8052 series chips The standard electrode, the approved electrode and the collection electrode are installed in the measuring cup; the control circuit is composed of a standard waveform generating circuit and a metering solenoid valve control circuit. The input port of the standard waveform generating circuit is connected to the waveform modulation output end of the central processing unit. For the waveform modulation signal sent out, the output port of the standard waveform generation circuit is connected to the standard electrode to generate a trapezoidal AC voltage drive signal; the metering solenoid valve control circuit is composed of a drive circuit and a high-voltage isolation circuit, and the solenoid valve drive output of the central processing unit The terminal is connected to the input port of the high-voltage isolation circuit, the output port of the high-voltage isolation circuit is connected to the input port of the drive circuit, and the output port of the drive circuit is connected to the metering solenoid valve; the measurement circuit consists of a standard base generation circuit, a filter shaping circuit, an amplification circuit, The high-voltage linear isolation circuit and the A/D conversion circuit are connected in sequence; the electric signal in the milk is collected through the approval electrode and the collection electrode, respectively, and the standard base generation circuit is approved, and then passed through the filter shaping circuit, amplifier circuit, high-voltage linear isolation circuit and A/D The D conversion circuit is input into the central processing unit for software processing and then output to the LCD screen or the database of the upper PC.

As shown in Figure 3: the above-mentioned standard waveform generating circuit is composed of inverter U5B, photoelectric coupler U7D, precise adjustable potentiometer R42 and operational amplifier U8A connected in sequence. The above-mentioned reference ground generating circuit is composed of precise adjustable potentiometer R43, operational amplifier U8B and several capacitors connected in sequence; the above-mentioned A/D conversion circuit is two TLC0831 chips.

As shown in Figure 4: the drive circuit and high-voltage isolation circuit in the metering solenoid valve control circuit are composed of photocoupler U7A, field effect transistor Q2, freewheeling diode D3 and filter capacitors C42, C34, and C35 connected in sequence.

As shown in Figure 5: the power supply of the present invention adopts a high-isolation power supply system, wherein U17 and U18 are high-isolation DCDC replacement modules.

The working principle of the present invention is: a 1kHZ trapezoidal AC voltage drive signal is applied to the standard electrode P2 to establish an electric field in the fresh milk. At this time, the measured fresh milk can be equivalent to a pure resistance under relatively static conditions; P1 and P3 are differential detection electrodes, which are precisely coaxial and equidistant from P2, and are used to measure the electric field formed by P2. At this time, there is a certain corresponding relationship between the current I of the electrode circuit and the conductivity k of the fresh milk to be measured, and the dynamic k value is finally obtained through certain errors, intelligent sampling and various calculations. The electrode material is metal platinum with strong corrosion resistance and good electrical conductivity. The electrode probe bracket is made of engineering plastic polycarbonate with small temperature coefficient and good chemical stability.

Claims (7)

1. A milk conductance dynamic on-line detection and milk volume measurement system, characterized in that it consists of a power supply, standard electrodes, approved electrodes, collection electrodes, metering solenoid valves, measurement circuits, control circuits and a central processing unit; standard electrodes, approved electrodes The electrodes and collection electrodes are installed in the measuring cup; the control circuit is composed of a standard waveform generating circuit and a metering solenoid valve control circuit. The input port of the standard waveform generating circuit is connected to the waveform modulation output end of the central processing unit to receive the waveform modulation signal sent by it. , the output port of the standard waveform generation circuit is connected to the standard electrode to generate a trapezoidal AC voltage drive signal; the metering solenoid valve control circuit is composed of a drive circuit and a high-voltage isolation circuit, and the solenoid valve drive output of the central processing unit is connected to the high-voltage isolation circuit. The input port is connected, the output port of the high-voltage isolation circuit is connected to the input port of the drive circuit, and the output port of the drive circuit is connected to the metering solenoid valve; the measurement circuit consists of a standard base generation circuit, a filter shaping circuit, an amplifier circuit, a high-voltage linear isolation circuit and A The /D conversion circuit is connected in sequence; the electrical signal in the milk is collected through the approval electrode and the collection electrode, respectively, and the standard base generation circuit is approved, and then input to the center through the filter shaping circuit, amplification circuit, high-voltage linear isolation circuit and A/D conversion circuit. After software processing in the processing unit, it is output to the LCD screen or the database of the host PC. 2. The milk conductance dynamic on-line detection and milk volume measurement system according to claim 1, characterized in that: the above-mentioned standard waveform generating circuit is composed of an inverter U5B, a photocoupler U7D, an accurate adjustable potentiometer R42 and an operational amplifier U8A connected sequentially. 3. The milk conductance dynamic on-line detection and milk volume metering system according to claim 1, characterized in that: the reference ground generating circuit is composed of an accurate adjustable potentiometer R43, an operational amplifier U8B and several capacitors connected in sequence; 4. The milk conductance dynamic on-line detection and milk volume measurement system according to claim 1, characterized in that: the above-mentioned A/D conversion circuit is two TLC0831 chips. 5. The milk conductance dynamic on-line detection and milk volume metering system according to claim 1, characterized in that: the driving circuit and the high-voltage isolation circuit in the metering solenoid valve control circuit are composed of a photocoupler U7A, a field effect transistor Q2, continued Flow diode D3 and filter capacitors C42, C34, C35 are sequentially connected to form. 6. The milk conductance dynamic on-line detection and milk volume measurement system according to claim 1, characterized in that: the central processing unit adopts 8052 series chips. 7. The milk conductance dynamic on-line detection and milk volume metering system according to claim 1, characterized in that: the above-mentioned power supply adopts a high-isolation power supply system.

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