The Research And Design Of A Tobacco Automatic Measuring System With High-Accuracy

With the main thread of the systematic precision improving, this paper, in mechatronics view, deals with the research and design of a tobacco automatic measuring system based on DCS from the conceive of the system structure, the analysis of the measuring precision, the design of the electric and machinery and the means of the anti-jamming and so on.The measuring is one of the key step of the process control, quality control and cost control in cigarette manufacturing, when it is the important technological means that realize production process automation, business scientific administration and safe production, and save energy and reduce the cost. The system applied in the production not only can improve cigarette quality and output, but also has lightened workers and improved productivity. So, it should be more practicable and popular.On the basis of the thinking of various kinds of automatic measuring equipment, according to the development of sensor, microprocessor network, communication technology, The system has adopted the distributing control method to measure the tobacco by computer, which is made up of a host computer and many servant microcomputers, host computer gives control task each servant microcomputer. In other words, every servant microcomputer can be regarded as one independent controlunit, transacts measuring and controlling affair on the spot, several servant controllers are networked by the digital communication interface, and link with industrial control computer, thus make up the distributing tobacco measuring system. It realized that data management be separating from process control, at the same time, it is scattered that the whole trouble risk of the measuring system, so its dependability more improves.In the thesis, it is expounded the process of setting up the measuring mathematics model, and the analyse of various kinds of factors which influences measuring precision, and then it is put forward that controlling algorithms and measuring equipment to solve the batching error. On the basis of comparing many kinds of control methods, In the article, it is presented that the microcosmic of dynamic measurement should be changed into the static measurement, using the fluid control theory, the system has adopted the adaptive control algorithm to solve "burden error", which reduces the dynamic error. On the other hand, it is brought forward that some approaches to reduce the error from the machine, electric hardware and software of the equipment. Especially it is considered that its mechanical structure, size of form, material performance and the strength state in the machine designing, which make the mechanical resonance totally separated from the bandwidth of the control system. Namely the jamming signals emerging from mechanical resonance are totally filtered by the wave circuit, the means have dispel the impact of the mechanical resonance, and have broken through routine anti-jamming means and measures.The tobacco measuring system is made of one industrial control computer (management grade) and nine measuring controllers (control grade). The industrial contro' computer has adopted the ADVANTECH610 product, the measuring controllers have adopted the single-chip microcomputer system, whose MCU is AT89S52, whose A/D converter adopts MAX180, whose low-pass filter is MAX293, whosecommunication interface of RS232 adopts MAX232, 75174, 75175, The Watchdog of the MCU is MAX705 and the system uses the switch power to supply power. The application packages of the system are complied by VC6.0 programming system, and its relevant software packages are designed, including the data management, the data acquisition, the wave-percolation, the control etc. In addition, some methods of anti-jamming that were adopted in this system are also studied, including the methods of hardware anti-jamming and software anti-jamming.