CN103364046A - Intelligent air interface type water level gauge and water level measurement method - Google Patents

Abstract

The invention provides an air-mediated intelligent water level gauge and a water level measurement method. The air-mediated intelligent water level gauge includes a processor, a storage unit, a power supply unit, a transmission module and a water level acquisition unit, wherein the storage unit, the transmission module and the water level acquisition The units are all connected to the processor and the power supply unit, and the power supply unit is connected to the processor; the water level acquisition unit includes a pressure sensor and a sealed air pipe, and the sealed air pipe is sleeved on the pressure sensor connection port, and the diameter of the pressure sensor connection port is equivalent to the diameter of the sealed air pipe. The method of the invention converts the hydraulic pressure into air pressure changes by sealing the air pipe, collects the air pressure changes through the pressure sensor, and calculates the depth from the detection point to the liquid surface according to the air pressure changes, and obtains the water level value. The invention has the advantages of small size, convenient use, accurate measurement, low environmental dependence, etc., and can be widely used in industrial, water conservancy and agricultural production in various environments.

Description

Air-mediated intelligent water level gauge and water level measurement method

technical field

The invention belongs to the technical field of water level measurement, in particular to an air-mediated intelligent water level gauge and a water level measurement method.

Background technique

With the increasing scarcity of water resources, how to accurately measure the consumption of water resources and realize the efficient, reasonable and accurate use of water resources has become one of the key needs of modern agricultural development. Modern water level gauges with accurate, automatic recording and remote transmission functions can better meet the above needs, so they have been greatly used and developed.

Different from the early self-recording water level gauges, modern water level gauges mostly use sensors to sense water level changes. According to the working principle of sensors, they can be divided into float type water level gauges, pressure type water level gauges and bubble type water level gauges. Although these types of water level gauges can meet the needs of water level measurement, they also have many shortcomings because of their strong pertinence to the application environment: the float type water level gauge needs to build a special logging well, and the investment cost is high; the pressure type water level gauge Affected by the measurement water quality conditions, the error is relatively large; the device of the bubble water level gauge is complicated, the cost of financial and material resources is high, and the data acquisition is slow. In addition, most of the existing water level gauges use mains power or solar power to provide power, which is easily affected by weather, power supply conditions, and transmission lines; in terms of data transmission, the existing water level calculation and remote control center mostly use wired transmission, which is not conducive to large-scale application.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention proposes a gas-mediated intelligent water level gauge and a water level measurement method that are convenient to use, accurate in measurement, and low in environmental dependence.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

An air-mediated intelligent water level gauge, including a processor, a storage unit, a power supply unit, a transmission module and a water level acquisition unit, wherein the storage unit, the transmission module and the water level acquisition unit are all connected to the processor and the power supply unit, and the power supply unit and the processing The water level acquisition unit includes a pressure sensor and a sealed air pipe, the sealed air pipe is sleeved on the pressure sensor connection port, and the diameter of the pressure sensor connection port is equivalent to the diameter of the sealed air pipe.

The pressure sensor mentioned above is a silicon integrated pressure sensor.

The above-mentioned sealed air pipe is a rubber hose or a seamless steel pipe, which has corrosion resistance.

The above-mentioned transmission module is a wireless transmission module.

The above-mentioned power supply unit is a lithium battery.

The above-mentioned storage unit is a TF card, and stores data in the FAT32 file system.

The gas-mediated intelligent water level gauge of the present invention also includes a display module.

A water level measurement method converts hydraulic pressure into air pressure changes through a sealed air pipe, collects air pressure changes through a pressure sensor, and a processor calculates the depth from the detection point to the liquid surface according to the air pressure changes, and obtains the water level value.

The above-mentioned processor calculates the depth from the detection point to the liquid surface according to the change of air pressure, which specifically includes the steps:

The pressure sensor outputs a voltage V _out after sensing the air pressure change;

The processor calculates the air pressure change value P according to the output voltage V _out , which is the hydraulic pressure at the detection point;

The processing calculates the depth from the detection point to the liquid surface according to the air pressure change value P and the liquid density.

The water level measuring method of the present invention also includes the steps of:

Judging whether the water level exceeds the limit according to the obtained water level value and the water level alarm limit, if the water level exceeds the limit, an alarm message is sent to the remote control center through the transmission module; if the water level does not exceed the limit, the water level value is saved to the storage unit as historical data. The method of sending alarm information to the remote control center through the transmission module adopts network mode, short message control mode or telephone control module.

In the water level measurement method of the present invention, the processor judges whether it is necessary to collect water level data or report the water level data to the remote control center according to the preset data collection cycle and the regular reporting cycle, and when the water level data does not need to be collected and the water level does not need to be reported to the remote control center Data, the water level gauge is in sleep mode, that is, the processor is in sleep mode, and the transmission module, display module and water level acquisition unit are turned off.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The present invention adopts the air-mediated passive contact method to collect water level data. The device is portable and easy to install. It does not need to build logging wells, complex devices and heavy gas cylinders. It can greatly reduce power consumption and has good stability; When it is fast, it can also quickly collect water level data, with high precision, good compatibility, and low dependence on the environment. It can be widely used in industrial, water conservancy, and agricultural production in various environments.

2. The water level measurement method of the present invention is unique. The water level is converted into air pressure change, and the water pressure perception is transformed into air pressure perception. The pressure sensor does not directly contact the liquid, which can prevent clogging and scaling, thereby prolonging the service life of the pressure sensor.

3. The preferred solution of the present invention uses a lithium battery for independent power supply, which has a long service life and is not affected by weather and mains power supply conditions. It is convenient to monitor the water level at any time, and is especially suitable for the itinerant detection of field canals and wells where no power supply can be provided on site. , strong reliability.

4. The preferred solution of the present invention uses wireless communication to transmit the collected data to the remote control center, without wiring, easy to install, and has great flexibility and accuracy.

5. The present invention realizes the FAT32 file system storage of the water level data through the storage unit, so that the storage unit can be recognized by the PC and directly read and write the data stored in it, which is convenient for checking and saving the historical water level data

6. The present invention integrates the control device into the casing, which has a compact structure, and the casing also has the advantages of waterproof, moisture-proof, anti-electromagnetic interference, anti-lightning strike, etc., and has strong practicability. Here the control device refers to a processor, a power supply unit, a transmission module, a storage unit and a pressure sensor.

7. When the water level gauge of the present invention does not need to collect water level data or report water level data, it is in a sleep mode, which can reduce power consumption.

8. The present invention can choose SMS control mode, network mode or telephone control mode to communicate with the remote control center according to the actual situation, which is convenient and flexible.

Description of drawings

Fig. 1 is the schematic diagram of working principle of water level acquisition of the present invention;

Fig. 2 is a structural block diagram of a kind of concrete implementation of the present invention;

Fig. 3 is the working flow of the water level gauge of the present invention.

Among them, 1-housing, 2-display window, 3-sealed gas pipe, 4-sealed connection port, 5-antenna.

Detailed ways

The air-mediated intelligent water level gauge of the present invention converts hydraulic pressure into air pressure change, changes hydraulic pressure perception into air pressure perception, senses air pressure change through a pressure sensor, and calculates the water level value according to the air pressure change.

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

See Figures 1-2. The water level gauge in this implementation includes a processor, a storage unit, a power supply unit, a display module, a transmission module and a water level acquisition unit. The processor is an MSP430 low-power series microprocessor; the storage unit is a TF card. The FAT32 file system storage of water level data can be realized, which can be recognized by the computer and directly read and write the data stored in the storage unit; the power supply unit is a lithium battery; the display module includes a display circuit and a display screen; the transmission module is a wireless transmission module and connected to an antenna , The frequency range of the antenna used is 900/1800MHz, and the maximum power is 50W.

The water level acquisition unit includes a pressure sensor and a sealed air pipe 3, the pressure sensor is an MPX5010DP silicon integrated pressure sensor, and the sealed air pipe 3 is a rubber hose or a seamless steel pipe with good corrosion resistance. The airtight air tube is sleeved on the protruding connection port of the silicon integrated pressure sensor, and is sealed with solid gel. See the sealing connection port 4 in Figure 1 for the connection. The diameter of the silicon integrated pressure sensor connection port is equivalent to the diameter of the sealed air pipe. When in use, one end of the airtight tube extends into the liquid, and the end of the air tube is fixed at the detection point. The liquid at the detection point squeezes the air in the sealed tube, so that the hydraulic pressure at the detection point is transmitted to the connection port of the pressure sensor through the sealed air tube.

A specific method for fixing one end of the sealed air pipe 3 to the detection point is: cover a section of hard pipe, which can be a metal pipe or a hard plastic pipe, on the sealed air pipe, and fix the hard pipe to a bracket, and the bracket is fixed on the bottom bed or side of the channel. bed.

The processor, storage unit, power supply unit, display module and transmission module of the present invention are all placed in the housing 1. In order to ensure the waterproof, moisture-proof and anti-electromagnetic interference of the housing 1, the housing 1 is a sealed stainless steel or plastic housing. . The casing 1 is provided with a transparent display window 2 through which the content displayed on the display screen can be observed.

The principles and theoretical basis involved in the present invention are as follows:

When the water level gauge collects water level information, it hydraulically compresses and seals the air in the air pipe, and hydraulically transmits the detection point to the pressure sensor; calculates the depth from the detection point to the liquid surface according to the output voltage of the pressure sensor, and obtains the water level value.

Taking the MPX5010DP silicon integrated pressure sensor as an example, the pressure sensor forms an output voltage V _out by sensing the air pressure change in the sealed air tube:

V _out ＝V _s ·(0.09×P+0.04)±5.0%V _Fss (1)

In formula (1):

V _S is the sensor input voltage, in this specific embodiment, V _S =5.0V;

V _FSS is the interference voltage caused by the error:

V _FSS = Pressure.Error×Temp.Factor×0.09×V _S (2)

Temp＝0～85℃（3）

Pressure.Error is the error generated during the pressure acquisition process. When the pressure to be measured is within the range of 0 to 10kPa, the error does not exceed ±0.5kPa. When the pressure to be measured is not within this range, the error is greater than ±0.5kPa;

Temp.Factor is the coefficient of pressure acquisition results affected by temperature;

Temp is the best temperature range for the sensor to work. When working in the temperature range of 0°～85°C, Temp.Factor=1, that is, the acquisition results will not be affected by temperature changes; when the sensor works at -40°～0°C or 85°～ At 125°C, Temp.Factor changes linearly with increasing or decreasing temperature, the highest being 3.0.

The output voltage V _{out of} the pressure sensor is converted into the corresponding ADC value and then transmitted to the processor. The processor obtains the pressure value P according to the formula (1), that is, the hydraulic pressure at the detection point; the detection point is calculated using the liquid depth-pressure formula (4) Depth h to liquid surface:

P = ρgh (4)

In formula (4):

ρ is the density of the liquid, g is the acceleration of gravity; the depth h from the detection point to the liquid surface can be calculated from P and ρ, and h plus the base value of the liquid level is the measured water level value. The base value of the liquid level is the distance from the detection point to the bottom of the water.

Fig. 3 is the working flow of the water level gauge of the present invention. When the water level gauge is powered on, it detects the operating status of the storage unit, transmission module, and display module. If a fault is detected, a fault prompt will be generated according to the fault type; if there is no fault, the data acquisition cycle and timing will be initialized according to the preset value. The operating parameters such as the reporting period and the water level alarm limit limit will be started immediately. When the water level gauge of the present invention does not need to collect water level information and does not need to report water level data, it is in the dormant mode. At this time, the processor is in the dormant state, and the wireless transmission module, the display module and the water level acquisition unit are all closed, and the real-time clock unit is mainly kept working. .

Determine whether to collect water level data according to the data collection cycle. When it is necessary to collect water level data, the real-time clock unit generates a corresponding interrupt, wakes up the processor, the processor enters a normal working state, and then sends a level signal to conduct the triode connected to the ADC module (analog-to-digital changer) in the pressure sensor; the ADC module Start to work, the processor continuously reads the ADC value output by the ADC module, after the ADC value is stable, takes the average value of a series of ADC values read, and calculates the real-time value according to the ADC average value, formula (1) and formula (4) The water level value, the process takes about 2 to 3 seconds, and at the same time, the processor controls the display module to update and display the real-time water level value.

After obtaining the real-time water level value, judge whether the water level exceeds the limit according to the water level alarm limit. If the real-time water level value exceeds the alarm limit, turn on the wireless transmission unit, establish a communication connection with the remote control center, and send the water level overrun alarm information to the remote control center, disconnect the communication connection with the remote control center after sending, and turn off the wireless transmission unit; if the communication connection with the remote control center cannot be established successfully, the SMS control mode or telephone control mode can be used to communicate with the remote control center, and the wireless transmission unit is turned off after sending. If the real-time water level value does not exceed the alarm limit, the water level data collected this time will be saved to the file system as historical data, and then the water level gauge will enter the sleep mode and wait for the next wake-up.

Determine whether to collect and report water level data according to the regular reporting period. When a report is required, the real-time clock generates a corresponding interrupt, wakes up the processor, and the processor enters a normal working state. First, the processor reads the water level data collected and saved between the end of the last report and this report, turns on the wireless transmission unit, establishes a communication connection with the remote control center, and sends the water level data to the remote control center. Open the communication connection with the remote control center and close the wireless transmission unit; if the communication connection cannot be successfully established with the remote control center, the processor uses the SMS control mode or the telephone control mode to communicate with the remote control center, and closes the wireless transmission unit after sending. After the report is over, turn off the wireless transmission unit, and the water level gauge enters the sleep mode, waiting for the next wake-up.

In order to improve the flexibility of the communication between the water level gauge and the remote control center, the communication between the processor and the remote control center of the present invention not only adopts the traditional network mode, that is, the server login mode for exchanging information, but also includes the SMS control mode and the telephone control mode. The SMS control mode means that the processor exchanges information with the remote control center by sending SMS commands to the mobile phone number of the remote control center; the phone control mode means that the processor calls the mobile phone number of the remote control center by telephone to exchange information with the remote control center.

Claims (10)

1. A gas-mediated intelligent water level gauge, characterized in that it comprises: A processor, a storage unit, a power supply unit, a transmission module and a water level acquisition unit, wherein the storage unit, the transmission module and the water level acquisition unit are all connected to the processor and the power supply unit, and the power supply unit is connected to the processor; the water level acquisition unit includes pressure sensors and The airtight tube is sleeved on the connection port of the pressure sensor, and the diameter of the connection port of the pressure sensor is equivalent to the diameter of the sealed air tube. 2. The air-mediated intelligent water level gauge according to claim 1, characterized in that: The pressure sensor is a silicon integrated pressure sensor. 3. The air-mediated intelligent water level gauge according to claim 1, characterized in that: The transmission module is a wireless transmission module. 4. The air-mediated intelligent water level gauge according to claim 1, characterized in that: The power supply unit is a lithium battery. 5. The air-mediated intelligent water level gauge according to claim 1, characterized in that: The storage unit is a TF card, and stores data with the FAT32 file system. 6. A water level measurement method, characterized in that: The hydraulic pressure is converted into air pressure changes by sealing the air pipe, the air pressure changes are collected by the pressure sensor, and the processor calculates the depth from the detection point to the liquid surface according to the air pressure changes, and obtains the water level value. 7. The water level measuring method according to claim 6, characterized in that: The processor calculates the depth from the detection point to the liquid surface according to the air pressure change as follows: The pressure sensor outputs a voltage V _out after sensing the air pressure change; The processor calculates the air pressure change value P according to the output voltage V _out , which is the hydraulic pressure at the detection point; The processing calculates the depth from the detection point to the liquid surface according to the air pressure change value P and the liquid density. 8. The water level measuring method according to claim 6, comprising the steps of: Judging whether the water level exceeds the limit according to the obtained water level value and the water level alarm limit, if the water level exceeds the limit, an alarm message is sent to the remote control center through the transmission module; if the water level does not exceed the limit, the water level value is saved to the storage unit as historical data. 9. The water level measuring method according to claim 8, characterized in that: The method of sending alarm information to the remote control center through the transmission module adopts network mode, short message control mode or telephone control module. 10. The water level measuring method according to claim 6, characterized in that: The processor judges whether it is necessary to collect water level data and report water level data to the remote control center according to the preset data collection cycle and regular reporting cycle. When the water level data does not need to be collected and reported to the remote control center, the water level gauge is in sleep mode. Mode, that is, the processor is in a dormant state, and the transmission module, display module and water level acquisition unit are turned off.

Images