A weighing instrument is a device that displays the weight and status of an object being measured. It is commonly referred to as a weighing display. Initially, electronic weighing instruments were analog-based, consisting of components such as an error amplifier, a reversible motor, a balanced bridge, an excitation power supply, a dial, and a pointer. These devices operated on the principle of an automatic balance electronic potentiometer. However, due to their slow weighing speed, limited functionality, and low accuracy, they have largely been replaced by modern digital weighing displays. The Components of an Electronic Weighing Instrument Structural Principle Modern digital scale instruments come in various forms, one of which is illustrated in Figure 1. The digital receiver receives electrical signals from the load cell, which can be either analog or digital. Typically, these signals are small analog voltages, often in the range of tens of millivolts. The circuit principle of the digital display is shown in Figure 2. The excitation power supply provides power to the load cell and also supplies the reference voltage for the A/D (Analog-to-Digital) conversion unit, with stability generally at 0.1% or higher. The amplification unit uses a measuring amplifier structure to receive and amplify the signal from the load cell, typically increasing it by hundreds of times. The filtering unit removes electrical noise from external sources and internal amplifier interference. The A/D conversion unit then converts the analog signal into a digital one, usually with 14 bits or more. The data processing unit, centered around a microprocessor and supported by peripheral chips, performs operations like data collection, calculation, and storage under program control, and sends the processed results to the appropriate interface. The display unit presents the weighing value and status in numerical or textual form, and can communicate with external devices through the interface. Schematic Diagram of the Weighing Instrument – Circuit Diagram Performance Characteristics The performance of digital instrumentation covers five key areas: metrological performance, functionality, environmental adaptability, security, and reliability. Compared to general digital weighing instruments, digital displays offer five distinct advantages: 1) a self-contained sensor excitation power supply for easy use; 2) ratiometric A/D conversion and frequency multiplication technology for long-term metrological stability; 3) software that realistically simulates weighing characteristics such as vibration, air balance changes, and material drop, resulting in fast, accurate, and stable readings; 4) a configurable setting unit for parameters like zero calibration, maximum capacity, and indexing, offering strong versatility; and 5) an output interface that allows connection to various external devices, enabling convenient system control. Accuracy Levels According to OIML Recommendation No. 3, non-automatic scales are classified into four accuracy levels. In China, electronic weighing instruments are also divided into four grades—labeled I, II, III, and IV. The maximum allowable error for each class is 0.7 times the tolerance of the corresponding instrument class. Netizens Explain the Basic Architectural Principles of Scale Instruments The architecture of a scale instrument is actually quite straightforward. A power supply provides energy to all components. An AD (Analog-to-Digital) section is responsible for amplifying the sensor’s analog signal and converting it into a digital signal. A central processing unit, commonly known as a single-chip microcontroller (MCU), processes this data. The weight signal is converted and decoded into a readable format for the display. Most instruments include a keyboard for user input, and many also feature parallel print ports, micro-drives, RS232 or RS485 interfaces for communication with host computers or other devices. Some models support 4-20mA current loop interfaces for integration with PLCs in industrial settings. High-end versions may even include CAN bus or Ethernet interfaces. While some instruments have a USB interface, it is rarely used due to its short transmission distance, so it is not commonly found in scale instruments. Stay tuned for more updates Tags: electronic weighing instrument, structure, principle Previous: The application of single-chip microcomputer in EDM machine Next: How to identify the quality of bathroom hardware accessories Wooden Nightstand,Wooden Bedside Table,Bedroom Furniture Nightstand ,Solid Wooden Nightstand Changzhou Offistyle Furniture Co., Ltd. , https://www.offistylefurniture.com