Design Of Calibration System Of Electrical Instruments In Locomotives Based On Embedded System Technology

Electrical instruments of locomotives measure and indicate electrical voltage and current, helping drivers know the working status of different parts of locomotives and thus forming an important monitoring approach to ensure safe operation of locomotives. To guarantee electrical instruments of locomotive in good working conditions, periodic calibrations of instruments are mandatory.Based on the study of the latest development in hardware and software of calibration technology of electrical instruments and the design demand, the advanced technology of embedded system is introduced to solve the problem.Firstly, this thesis discusses the blue print of calibration system of electrical instruments. And then by using the technology of embedded system, the upper-end computer system and lower-end computer system are studied from the aspects of hardware and software respectively. The high accuracy measurement circuit and high accuracy output circuit based on MCU is studied as the main part of hardware work of lower-end computer. Joined with embedded software design pattern, the software flow charts of lower-end computer functions are given. As to the upper-end computer system, PC104 module is introduced as hardware platform. In terms of software of upper-end computer system, the customization of Windows CE platform is introduced in detail firstly. Then the key process of application software design by using .NET Compact Framework on Windows CE platform is given. The main research works are as follows:1. Design and implementation of high accuracy measurement circuit (MAX133), high accuracy output circuit (DAC714) and RS-422 communication circuit (MAX1490) based on AT89C52 MCU2. Building OS design of Windows CE 4.2 including OS customization, device driver loading and files configuration3. Developing application on Windows CE 4.2 platform by using C# programming language based on .NET Compact FrameworkThe design of hardware and debug of software have been completed at present. Additionally, functions and demands of the system are completely achieved.