The Network Measuring Control Technique The subject is undertaken by the group of electronics information subject in our school, including the specialty as electronics information engineering, electronics information science and technology, electronics science and technology (the direction of photoelectron) and communication engineering and so on.
Three mainstays of modern information technique are techniques of sensor, communications and computer which complete the information withdrawing, information transmission and information processing of the measured value. Presently, the transmission and processing of information have made a break progress; however the development of sensor lags correspondingly. At present, the requirement for automation degree, complexity and environment adaptability of various control system are more and more high, and information quantity we needed is more and more, which not only puts forward a very high request for measurement accuracy, speed of respond and credibility, but also needs long-distance transmission of the signals. Obviously, the conventional sensors can' the t satisfy the request, and main current and direction of sensors technique is to develop the competitive, subminiature, intelligent and internet sensors.
Along with the technical development of information, especially the unremitting progresses of calculator network, we put forward the new request of communication unction of the intelligent sensor. For carrying out the collaboration and unification of collection, processing and transmission of the information, it's necessary to combine computer network technique and intelligent sensor technique organically.
Modern bus is a full digital, open and duplex transmission network which links the intelligent equipment and console. It' the continual development of field-bus and broad application of intelligent sensor basing on field-bus communication negotiation that makes the communication technique of intelligent sensor into the stage of network measurement and control. The measure and control network can connect with Internet/Intranet passing the gateway and router. The development of spot-bus leads to field-bus control system (FCS) replacing dispersive-bus control system (DCS).
Network measuring control equipment acts as an independent node in the network in the measuring control network adopting field-bus and Ethernet. The information can be transmitted to any field where there are networks and the real-time, dynamic and on-line measuring control can be true. Comparing with the old measuring control technique, the system basing on network can save many wires, broaden the measuring control range and make the system expansion and maintenance convenience, because the network developed a key function in implement and completeness of the modern measurement task, i.e. the network really got involved the whole process of modern measurement and control. The study and application of Measuring control technique basing on network have meaningful graveness and broad foreground.
On the foundation of Research and teaching of our subject, it's an important part of the group of electronics information subject construction to carry on the research and application of network measuring control technique. The level of Research and teaching of this subject can be raised by buying equipment with yen loan. The students' ability of innovation can be brought up effectively and this subject can be constructed a point subject in our school the which can the beat solid the foundation for the requiring Hebei key laboratory.
1. The construction target
Theory problem about network measuring control will be studied thoroughly and more applying point in sewage processing and environment watching will be found.
The actual application of network structure and system such as Profibus and Ethernet will be studied and developed farther which accords with the developing trend of network measuring and control, and necessary soft-hardware platform for experiment and testing will be built.
The general, open and long distance data collection and information processing system will be developed which applies wireless transmission technique (including GPRS, GSM and CDMA).
The equipment of network measuring control will be developed which applied in sewage processing and environment inspect using new built-in chip such as ARM, SOC and DSP and the industrialization negotiation transformer among some standard string communication negotiation.
The measurement of spread frequency technique on Doppler ultrasonic flux and clay-water interface will be analyzed in theory and validated by experiment. The market conversion of the technique will be done establishing in the Tangshan which is the main producing area of ultrasonic flow meter.
2. The construction contents
This time, the subject construction of yen loan will be applied into some ways below:
The development plat of real time measuring control system basing on ARM: Combine ARM kernel processor (the 32bit RISC configurable of high capability, low cost) withμC/OS-Ⅱ(the real time embed multitask operating system of opening sound code), and add network transferring function for plat via embed TCP/IP protocol, then establish the new-style development plat of real time measuring control system.
At one time, it provides repeating use、high capability、graphical interface、base network soft-hardware plat and high capability development mode for inventing intelligent, miniaturization measuring control system. The data collection system basing on wireless transmission technology: Using existing commonality wireless network(GSM、CDMA or GPRS) to carry out collecting、transmission、managing for dispersive、important data. It has many purposes: street lamps inspect system; oil field long-distance inspect system; the city water supply inspect system; the real time inspecting of atmosphere quality and sewage discharge; individual orientation inspect system.
There are many unmanned guarding equipments or inspecting places which don't conform build lineate communication network. If we adopt optic fiber or broadcasting station for wireless communication, the money devotion is large and don't conform the need of moving. So the wireless data transmission is a perfect solving project.
The applications of spread spectrum technology in Doppler ultrasonic flux and liquid surface position measuring: Expand spectrum technique is a new technique of channel multiplexing in modern data transmission, and its bandwidth is more much bigger than the narrowest bandwidth that transmitting information needs. The band-spread is fulfilled by the method of coding and modulation, and it doesn’t correlate with the information data. In the receiver, the same spread spectrum code was used to demodulate correlatively and recover the information data. Because the spread spectrum technology enlarges spectrum of signal greatly, and sender achieves band-spread modulation through spread spectrum code sequence, and receiver uses correlative demodulation technology, so it has a lot of excellent performance, and can effectively resolve the problem that multiplex transmission brings. So we can realize the flowing speed orientation measurement, and eliminate the effect brought up by the laminar flow. The anti-jamming capability of spread spectrum system is strong, the wider the frequency band is, or the bigger match filter enlarging multiple is, and the stronger the anti-jamming capacity is. Using the characteristic, we can improve the anti-jamming capability to measure ultrasonic sound Doppler flux.
With application of digital signal processing technique: The digital signal processing technique is mainly applied in the processing and analysis of ultrasonic Doppler frequency moving signal. The theory study indicates that ultrasonic Doppler signal is produced by dispersion of many grains or air bubbles and Doppler signal is a narrow band signal which distributes at transmitting frequency. There is opposite relationship between average velocity of flow and average frequency of narrow band signal according to statistic theory, so we can transform the estimate of velocity of flow into that of average frequency of Doppler signal. There are many ways to estimate average frequency now. The frequent analysis method is to analysis the frequency chart of Doppler signal, and to get its power table density, then to get average frequency from its definition, but it is difficult to carry out in real-time, especially for the power stable estimate of Doppler signal. Now along with the maturity of digital signal processing technique, especially the development of DSP, it makes the application of frequency chart method become feasible. The subject will make use of technique of DSP to analysis the frequency chart of frequency moving signal.
3. The equipments purchase 99 series equipments will be purchased in this subject, and the sum adds up to RMB 1,531,660 Yuan, among these equipments, 62 series will be purchased using yen loan, and the sum adds up to RMB 1,037,370 Yuan, 37 series will be purchased using school copulate funds, and the sum adds up to RMB 494.290 Yuan.