It is not necessary to spend more money to improve the accuracy of the first-level testing machine for general material testing, but 0.5-level precision testing machine is needed for scientific research and material analysis. In fact, there is no obvious difference in technology between the 0.5-level and the first-level accuracy testing machine, and the method and means of verification are basically the same, which is repairing. On the other hand, with the development of sensor technology, the linearity of sensor elements has reached a very high level. As long as the measuring circuit is not defective and the anti-jamming performance is good, it is no problem that all the testing machines will reach the accuracy of 0.5 level, which is far beyond the limit of 0.5 level for electrical measurement. Relative errors in the definition of national standards need to be discussed.
At present, most of the deformation units adopt a single chip 24-bit ultra-low noise analog-to-digital converter, which integrates signal amplification and A/D conversion. Because this deformation unit has the characteristics of "taking single chip as the core and few peripheral circuits", the system has the characteristics of high precision, good stability, small linear error and strong anti-jamming ability. Reasonable design and good process layout make the amplifier very stable. The single chip computer unit connected with the amplifier, as the heart of the host computer, is responsible for the amplifier range conversion, data acquisition, data transmission, universal testing machine mode selection and liquid crystal display, direct reading digital quantization, while these data can be output through RS232 ports, and other devices can be accepted through RS232 ports. Provisional instructions. Due to the use of single-chip computer control, this unit has the function of automatic zero-setting. When zero-setting, only pressing the zero-clearing key in the main interface can automatically zero-clearing the whole process, and the time of zero-clearing is very short.
The principle of deformation measurement is as follows:
Strain extensometer is composed of elastic elements and strain gauges pasted on it. When the moving arm of extensometer is stressed, the elastomer deforms and the resistance of strain gauges pasted on it changes. The unbalanced output of the bridge balanced by the universal testing machine is proportional to the voltage signal output of the deformation. The electric signal output by the extensometer is extremely weak. It must be amplified before it can reach the required value. This work is amplified and converted by A/D converter, and then sent to a single chip computer for processing. It is displayed in a direct reading way. At the same time, it is transmitted to the computer through RS232 for data processing.
According to the maximum load of the test material, the maximum load (i.e. range) of the test machine is selected. It is recommended that the test load of the material should be 70%-90% of the range of the tension test machine, which not only ensures the resolution of the test, but also prolongs the service life of the test machine. The bigger the power, the more expensive the machine is. So when choosing the pulling machine, it is not the bigger the better, but the universal testing machine to choose the strength range suitable for your company's products. If you don't know how hard your products need, our engineers can help you calculate the strength needed, so as to select the pulling test machine suitable for your products.