First, the term explanation

     A measuring instrument for measuring the mass (weight) of the object by using gravity acting on the object, and the scale equipped with the electronic device is an electronic scale.

Second, the working principle

     The weighing instrument converts gravity into an analog signal of voltage or current through a weight sensor mounted on the mechanism, and is amplified and filtered to be converted into a digital signal by the A/D processor, and the digital signal is calculated by a central processing unit (CPU). Processing, and the peripheral functions and various interface circuits are also connected to the CPU application, and finally displayed by the display screen in a digital manner.

    Electronic scale schematic:

 

   Program K/B (button) ↑ Fx → Sensor → OP Zoom → A/D Converter → CPU → Display Driver → Display ↓ Memory

 

   1. Weight sensor 2. Amplifier circuit 3. Filter circuit 4. Analog to digital converter 5. Central processor 6. Power supply circuit 7. Button 8. Case 9. Mechanism 10. Weighing pan

 

Weighing instruments can be divided into mechanical and electronic

 

Classification of electronic scales (weighers can be divided into mechanical and electronic)

 

1 Working principle: The working principle of electronic type is composed of electronic components (loading sensor, AD conversion circuit, single-chip circuit, display circuit, keyboard circuit, communication interface circuit, regulated power supply circuit, etc.).

2 Function: The electronic weighing instrument adopts the integrated electronic weighing device of modern sensor technology, electronic technology and computer technology to meet and solve the "fast, accurate, continuous and automatic" weighing requirements proposed in real life, and effectively eliminate it. Human error makes it more in line with the application requirements of legal metrology management and industrial production process control.

3 Health scales are a classification of the use of scales (both mechanical and electronic), which are inexpensive, can help people effectively monitor their weight changes, new products can also detect their own fat content, and Some humanized affiliate functions. May not be a measuring instrument.

4 The electronic weighing instrument is a nationally compulsory measuring instrument. Its qualified product is a standard with a verification index value e and a subdivision value D. It is a product protected by the national measurement method. There is a product called “Human Scale” in the classification of electronic scales, which can be checked in the metrology department and the weighing is very accurate.

 

Interpretation of the principle block diagram of the electronic scale

 

The first part is the principle block diagram of the electronic scale:

 

Program K/B (button)

 

↑ Fx → Sensor → OP Zoom → A/D Converter → CPU → Display Driver → Display Memory

 

Workflow Description: When an object is placed on the weighing pan, pressure is applied to the sensor, which deforms, causing the impedance to change, and using the excitation voltage to change, outputting a varying analog signal. The signal is amplified by an amplifying circuit and output to an analog to digital converter. The digital signal converted into a convenient processing is output to the CPU arithmetic control. The CPU outputs this result to the display according to keyboard commands and programs. Until this result is displayed.

 

The second part of the scale classification: 1. According to the principle: electronic scale mechanical scales mechanical and electrical combined scales 2. According to the function points: counting scales pricing scales weighing scales 3. According to the purpose: industrial scales commercial scales special scales

 

The third part of the scale: 1. Desktop scale refers to the electronic scale with the full weighing below 30Kg 2. The scale refers to the electronic scale with the full weighing within 30-300Kg 3. The weighbridge refers to the electronic scale 4 with the full weighing above 300Kg Precision balance

 

The fourth part is classified according to the accuracy: Class I: Special balance precision ≥1/100,000 Class II: High-precision balance 1/10,000 ≤ Precision <1/100,000 Class III: Medium precision balance 1/1000 ≤ precision <1/1 million class IV: ordinary scale 1/100 ≤ precision <1/1000

 

The fifth part of the terminology: 1. Maximum weighing: One electronic scale does not count the tare, the maximum load that can be weighed; 2. Minimum weighing: a relative of a scale that appears below this value Error; 3.Safety load: 120% normal weighing range; 4. Rated load: Normal weighing range; 5. Allowable error: Maximum deviation allowed by level inspection; 6. Sensing: Can be displayed by an electronic scale Minimum scale; usually denoted by “d”; 7. Analytical quantity: an electronic scale with counting function, the smallest scale that can be distinguished; 8. Resolution: An electronic scale with counting function, which has