The direct weighing runoff and sediment monitoring instrument at the checkpoint is a more systematic and comprehensive standard experimental equipment developed and produced by our company based on the continuous development of modern electronic technology, soil physics, microclimate and other disciplines to measure the runoff volume and sediment content of runoff plots with changes in rainfall. It studies the soil erosion status under different rainfall amounts by analyzing the recorded runoff. The instrument adopts advanced high-resolution weighing system and liquid level measurement system, equipped with intelligent data collector and signal sensor, which can simultaneously detect the size of rainfall. And the measured data is analyzed, processed, recorded and stored in real-time online, achieving high-speed, accurate and user-friendly data collection, greatly improving work efficiency and reducing labor intensity. Suitable for long-term monitoring of hydrological cycles in ecosystems such as farmland, grasslands, forests, and river wetlands.

The direct weighing runoff and sediment monitoring instrument at the checkpoint is a more systematic and comprehensive standard experimental equipment developed and produced for measuring the runoff and sediment volume of runoff plots with changes in rainfall. It studies the soil erosion status under different rainfall amounts by analyzing the recorded runoff. The instrument adopts advanced high-resolution weighing system and liquid level measurement system, equipped with intelligent data collector and signal sensor, which can simultaneously detect the size of rainfall. And the measured data is analyzed, processed, recorded and stored in real-time online, achieving high-speed, accurate and user-friendly data collection, greatly improving work efficiency and reducing labor intensity. Suitable for long-term monitoring of hydrological cycles in ecosystems such as farmland, grasslands, forests, and river wetlands.

system composition

lFollowing the innovation of sensor technology and detection technology has improved the measurement accuracy of relevant parameters

lFurther improved and enhanced the efficiency of the direct flow sediment monitoring instrument in use, reducing labor intensity and maintenance workload.

lThe cylinder structure and working principle are shown in the figure, mainly including the box body (the core of the main system), weighing system, liquid level measurement system, rainfall collection system, and data acquisition and monitoring system.

Product Features

The complete system of the direct soil evapotranspiration meter can be divided into two parts: hardware and software

lMeasurement part: composed of sampling bucket, weighing system platform, liquid level measurement platform, rain gauge, and supporting sensors, etc

lData transmission part: composed of data conversion module, amplifier, network module, and power supply system, etc

Terminal display part: composed of data collector, main controller, supporting software, and LCD screen, etc

Solution

lWeighing principle scheme

The principle of the weighing mechanism of the direct weighing permeameter is shown in the following figure: the weighing system purchases a dedicated weighing sensor, which acts on the weighing platform to directly weigh the total weight of the barrel. Use a sewage pump to extract the slurry mixture from the nozzle into a sampling bucket.

The weighing sensor adopts high-precision weighing sensor and is located under the weighing platformOne fulcrum supports the weighing soil box, and a weighing sensor is placed at the fulcrum for weighing calculation.

The main performance indicators of weighing sensors are as follows:

lWeighing range:0~1000.0Kg, resolution 0.01Kg

lComprehensive accuracy:0.01%

lWeighing sampling rate:1 second

lOutput impedance:2.0（+/-0.25%）

lMaterial: Stainless steel, fully welded and sealed, and passed throughIP68 industrial protection level standard

Due to the inherent zero drift and creep characteristics of weighing sensors, measurement accuracy is inevitably affected under long-term stress conditions, and the error parameters of each sensor are different. Our company has specially designed and developed weighing sensor calibration equipment and methods to test and calibrate its range, stability, repeatability, and sensitivity. The testing of the measuring range is carried out by sequentially loading known weight weightsThe method of gradually reducing the load from 2 to 300 kg; To test its stability, a 300kg weight was loaded onto the weighing sensor within 2 hours, and the degree was measured every 30 minutes to determine its stability. The sensitivity of the weighing sensor is measured by sequentially loading and unloading 10g, 20g, 20g, 30g, 20g, 100g, 100g, and 200g. Thus effectively removing measurement errors caused by zero drift and creep.

lPrinciples of Liquid Measurement

In measurement, ultrasonic pulses are emitted by sensors (transducers), and the sound waves are reflected by the liquid surface and received by the same sensor or ultrasonic receiver. They are converted into electrical signals through piezoelectric crystals or magnetostrictive devices, and the distance from the sensor to the measured liquid surface is calculated based on the time between the emission and reception of the sound waves. Due to the use of non-contact measurement, the measured medium is almost unrestricted and can be widely used for measuring the height of various liquid and solid materials.

The working principle of an ultrasonic level gauge is that high-frequency pulse sound waves are emitted by an ultrasonic transducer (probe), and when they encounter the surface of the measured level (material), they are reflected back and converted into electrical signals by the transducerThe propagation time of sound waves is directly proportional to the distance they travel to the surface of an object The relationship between sound wave transmission distance S, sound velocity C, and sound transmission time T can be expressed by the formula: S=C × T/2

Due to the certain width of the emitted ultrasonic pulses, the reflected waves in a small area close to the transducer overlap with the emitted waves, making it difficult to identify and measure their distance values. This area is called the measurement blind spot. The size of the blind spot is related to the model of the ultrasonic level gauge.

The probe emits ultrasonic waves, which are then reflected by the liquid surface and received by the probe. The distance between the probe and the liquid (object) surface is proportional to the time the ultrasonic waves have passed

distance[m] =Time x Sound Speed/2 [m]

Temperature compensation formula for sound velocity: environmental sound velocity=331.5+0.6 x temperature

lPrinciples of runoff flow measurement

Made based on the actual runoff range of the checkpointA 30 ° angle measuring weir can accurately reflect the flow rate results. It is calculated by measuring the high and low water levels flowing through the weir mouth using an ultrasonic water level gauge and using the weir formula to calculate the flow rate. Relevant parameters can be modified through management software or calculated through calibration sections to improve calculation accuracy.

lPrinciples and Solutions of Data Collection

The data collection of this system is all automated, and the data can be directly saved to the collector or saved in the form of data files according to the designed cycle. It can also be remotely transmitted and monitored through the network.

technical parameter

lWater level range：0~30m, accuracy 5mm

lRainfall accuracy：0.2mm

lMeasurement range of sediment content：0~300.0kg/m2, with an error of less than 5%

lworking temperature：0℃~60℃

lWorking conditions：220V AC isolated power supply or solar energy

ldisplay：4 lines of Chinese and English characters

ltransport Out：RS232, RS485, WIFI, GPRS, etc

lWeighing sampling rate：Adjustable from 60 to 3600s