Electronic truck scale history and working principle

Truck scale, commonly known as platform scale, is the main weighing equipment for bulk cargo metering.

The truck scales that were common before the 1980s were generally mechanical mechanical truck scales that were constructed using the principle of leverage and were also referred to as mechanical floor scales. In the mid-1980s, as high-precision load cell technology became more and more mature, mechanical loadometers were gradually replaced by electronic truck scales with high precision, good stability, and easy operation.

Electronic truck scales use the principle of strain measurement. A strain gauge is attached to the elastic body of the load cell to form a Wheatstone bridge. At no load, the bridge is in equilibrium and the output is zero. When the elastic body is subjected to a load, each strain gauge generates a strain proportional to the load, and the external load can be measured from the output voltage.

Structural composition and working principle 1, structural composition Electronic truck scale mainly by the carrier, weighing display instrument (hereinafter referred to as the instrument), weighing sensor (hereinafter referred to as the sensor), connecting parts, limit devices and junction boxes and other components, You can also choose to print external devices such as large-screen displays, computers, and power supplies.

2. Working principle When the weighing object or truck is placed on the carrier platform, the gravity is transmitted to the weighing sensor through the carrier under gravity, so that the elastic body of the weighing sensor is deformed and attached to the elastomer. The strain gage bridge is out of balance and outputs an electrical signal proportional to the weight value. The signal is amplified by a linear amplifier. After A/D is converted into a digital signal, the weight signal of the instrument's microprocessor (CPU) is directly processed to display the weight data. After configuring the printer, you can print and record weighing data. If you configure the computer, you can enter the measurement data into the computer management system for comprehensive management.

When the maintenance of the electronic truck scale fails and the electronic truck scale cannot work, the cause of the fault should be found according to the structure of the electronic truck scale. The simplest way to determine if a fault is occurring in a load cell or a weighing display is to use a sensor simulator.

The load cell simulator is based on the working principle of the resistance strain type load cell and can simulate various loading conditions of the resistance strain type load cell. This simulator is similar to a DC standard voltage source and can provide analog voltage signals of various weighing ranges to weighing display instruments. The excitation voltage of the sensor simulator is derived from the bridge voltage of the weighing indicator and is a passive passive signal generator. The sensor simulator can not only set and calibrate the weighing indicator in the laboratory, but also can find and find the cause of the fault in time in the field, so as to quickly eliminate the fault. It is an indispensable electronic automobile scale inspection and maintenance equipment.

Disconnect the signal cable between the junction box and the weighing display instrument, insert the socket of the sensor simulator into the indicator interface of the weighing indicator, and turn on the power to see whether the instrument works normally. If the meter is working properly, it means that the fault occurred in the weighing platform and caused by the load cell or military box. If the meter is not working properly, it means that the fault occurred in the weighing indicator.