Views: 1 Author: Site Editor Publish Time: 2022-04-27 Origin: Site
Who uses crane scales？
With the advancement of technology, the requirements for crane scales are also getting higher and higher. The main factors affecting its accuracy are: mechanical structure, sensors and digital display instruments. In terms of mechanical structure, due to the limitation of the strength and stiffness of the material structure, there will be errors in the transmission of force, and the output characteristics of the sensor are nonlinear.
The linearity error can not be ignored. Therefore, in the high-precision weighing occasion, it is urgent for the crane scale to automatically correct the nonlinearity of the system online. In addition, in order to ensure accurate and stable display, the internal resolution of the instrument is generally more than 4 times higher than the external display resolution, which requires the ADC to have enough conversion bits, and the use of high-precision ADCs naturally increases the cost of the system.
Based on the status quo of crane scales, this paper proposes a high-precision intelligent crane scale design scheme based on single-chip microcomputer control and load cells. By compensating the nonlinearity of the system in real time, the measurement accuracy has been greatly improved. Who needs these crane scales, SAINTBOND is here to tell you.
1. Overview of crane scale
For thousands of years, people's weighing methods have been using mechanical scales based on the principle of lever moment balance, ranging from Tianxingzi to large truck scales and rail scales. It was not until ten years ago that due to the rapid development of electronic technology, a new weighing method came out, which is the hanging scale.
2. Who will use what kind of crane scale
The crane scale is generally composed of sensors and secondary instruments. The working principle of the crane scale is: when weighing, the weight signal is applied to the sensor, the sensor converts the weight signal into an electric quantity signal, and then is amplified by the processing of the secondary instrument, and the weight value is displayed digitally, and some can also be printed. Record.
The sensors of crane scales Dynamometer are various, such as classification according to the power form of the sensor, which can be roughly divided into: resistive, capacitive, inductive and so on. The resistance strain gauge sensor is small in size and high in precision, but it is easily affected by environmental factors such as temperature and humidity, and its work is unstable. After taking measures such as sealing, heat preservation and compensation, the influence of environmental factors can be greatly eliminated. Most of the crane scales currently used are resistance strain gauge sensors. Capacitive sensors are bulky and their accuracy is slightly worse than that of resistance strain gauge sensors. But because the change of the capacitance can be easily converted into the change of the frequency, and the frequency can be processed as a digital quantity, so the comprehensive accuracy of the sensor and the secondary instrument can be greatly improved. Inductive sensors are less affected by environmental factors and have good durability, but their accuracy is not high. Generally, it is only used for occasions with low precision requirements such as weight limit and batching.
Crane scales have developed rapidly, and the types of crane scales Dynamometer cover almost all types of mechanical scales. And because of its own characteristics, it also adds some types that are difficult to achieve by mechanical scales, such as hook scales, trolley scales, dynamic belt scales and so on. In physical circulation, scales with a range of more than 1 ton are widely used. The most prominent advantages have three points: first, it can reduce operation links and workload, and improve production efficiency; second, it can reduce the labor intensity of weighing personnel and reduce labor Weighing error; the third is to facilitate automation. The trolley-type crane scale and the hook-type crane scale play a significant role in reducing operation links and workload and improving production efficiency. Both of these scales are used on cranes, which can simultaneously complete the weighing operation during the loading and unloading process of materials.
The trolley hanging scale is to install the sensor on the trolley of the bridge SAINTBOND crane. The hoisting mechanism on the trolley is fully supported by four sensors. The sensor and the secondary instrument in the driver's cab can be connected by cable, or wireless signal can be used to transmit information. The trolley crane scale is especially suitable for being installed on the overhead crane with frequent weighing operations, and has good adaptability to the use conditions and environmental conditions. The hook type crane scale is to hang the scale body with the sensor installed on the hook head of the crane, and then hang the weighed object under the scale body. The secondary instrument class is fixed on the scale body and becomes an integrated type. The secondary instrument can also exist independently from the scale body, which is called a split type. The weight value of the integrated hook hanging scale is directly displayed on the scale body by a digital tube or liquid crystal during weighing. The digital tube display is suitable for places with low light, such as night and indoors. The liquid crystal display is suitable for places with strong light. The integrated hook scale is convenient and simple to use, but when weighing, the scale body is hovering at a height of several meters from the ground, and the head should be carefully observed when reading the weight value displayed on the scale body. The split hook scale is equipped with a wireless signal transmitter on the scale body, and the secondary instrument receives the wireless signal to display the weight value. The scale body of this hanging scale is more impact-resistant and easy to use. The secondary instruments of the split hook scale are desktop, portable and hand-held as well as large-screen. The desktop is equipped with more functions because you don't have to worry about its size and weight. The hand-held one can read the weight value in the hand, which is very convenient to use. The large-screen display can read the weight value at the same time by many people within a certain distance. A SAINTBOND crane scale can be equipped with several different forms of secondary instruments at the same time. Users can choose one or several secondary instruments according to their own needs. In the early days, there was also a hook-type hanging crane scale that used a signal cable to connect the sensor and the secondary instrument, but it was eliminated due to inconvenience.
The advantage of the hook-type crane scale is that it is flexible and convenient to use, and it is suitable for the situation where the place of use is frequently changed. The scope of application in my country is wider than that of trolley-type Crane load monitoring systems. It has applications in factories, warehousing, railways, ports and other departments. The price is also lower than that of trolley-type crane scales. There are many manufacturers of hook-type crane scales, and the ORS series electronic crane scales produced by SAINTBOND Crane Scale Factory are outstanding in terms of accuracy, resolution and reliability. The Digital & Crane scale has only been produced and applied in my country for a short period of ten years. The initial secondary instrument of the crane scale is an electronic tube, which is large in size, poor in stability and reliability, and needs to be preheated before use. In recent years, crane scales have made rapid progress. With the support of materials and processes, the sensitivity, linearity, repeatability and other indicators of the sensor have reached a very high level. Secondary instruments generally use technologies such as integrated circuits and microprocessors, which reduce the volume and increase the function. The system accuracy of the crane scale has reached or surpassed the level of the Ⅲ-level scale, and many perfect shaped products have appeared, forming a series. Due to the various advantages of crane scales, the traditional mechanical scales are dwarfed in front of it, and it is the general trend that SAINTBOND crane scales replace mechanical scales.
3.The future development trend of crane scale is:
1. Further improve reliability and durability. The components of crane scales are much more than mechanical scales, and most of them are electronic components. Objectively, the probability of failure is higher than that of mechanical scales. It is particularly important to improve reliability. The scale body should withstand normal bumps in use and should not be too squeamish. Improved reliability and durability are key to crane scales competing with mechanical scales.
2. Reduce cost price. The current price of crane scales is still higher than that of mechanical scales, which affects the promotion and application of crane scales. It is not impossible to reduce the cost and sales price of the crane scale when the price of electronic components is reduced.
3. Further improve the secondary instrument and develop new functions. For example, increase the disk storage to facilitate the transmission of information to the computer; increase the function of voice reporting. It can also be specially designed according to user requirements, so that the crane scale can participate in the control of the automatic production process.