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1.概述随着冶金、电力、化工、石油、造纸和医药等工业的发展,环境污染日趋严重。工业自动化仪表在运输、贮存、安装和使用中可能经受到腐蚀和侵蚀影响,而导致仪表提早失效。为确保仪表长期可靠地工作,往往需要在设计、制造、工艺上考虑工作现场条件给其带来的种种影响。另一方面,用户也希望根据自己的使用环境等级合理地选择仪表,建造经济的安装场所,保证以最少的投资取得最大的经济效益。而国际电工委员会标准IEC654-4(1987)《工业过程测量和
1. Overview With the development of industries such as metallurgy, electric power, chemical industry, petroleum, papermaking, and pharmaceuticals, environmental pollution has become increasingly serious. Industrial automation instruments may be subject to corrosion and erosion during transportation, storage, installation, and use, resulting in premature failure of the instrument. In order to ensure long-term reliable operation of the instrument, it is often necessary to consider the various impacts on the work site conditions in the design, manufacture, and process. On the other hand, users also want to reasonably select meters based on their own use environment, build economical installation sites, and ensure maximum economic benefits with minimal investment. The International Electrotechnical Commission standard IEC654-4 (1987) "Industrial Process Measurement and