| It is very important to measure and control the molten steel level in continuouscasting. If the molten steel level in continuous casting is over-fluctuation, it wouldaffect the surface quality of the slab, and the worst case would cause productionaccidents such as steel overflow and breakout. Improving for detecting andcontrolling precision of the system，not only avoid those problems, but also canimprove production efficiency, reduce the labor intensity. Therefore,high-performance molten steel level detection and control technology research hasbecome an important research direction in the field of continuous casting.Base on a deeply research of other molten steel level detection, analysis theproblems of these systems, this thesis designs a new structure of molten steel leveldetection for mould. And the main contents of this thesis are listed as below.1. In order to eliminate the interference between the traditional sensor coil andtransmitter circuit during long-distance transmission, a new integrated digitaleddy current sensor was designed by Pre-Signal processing circuit and digitaltransmission.2. To improve the response speed, detection accuracy and data processingcapabilities, a new system hardware structure was designed under the hierarchicalguidance and the modular design concept. The new structure called three controllayers (sensing layer, control layer and management layer) is composed byembedded system, control ling microcontroller and sampling microcontroller.3. This thesis completes all of the hardware and software of the System. Hardwareincludes Amplifier circuit, Excitation circuit, Detector circuit, The DC amplitudemodulation negative feedback circuit, A/D and D/A circuits,4-20mA convertercircuit, Communications circuits and so on. Using AVR C language to completethe software design for sensing layer and control layer.At the end of the thesis, briefly introduces the system implementation, the realrunning in the industrial field and the testing of main technical indicators. |
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