一、前言 据有关方面统计,到2000年我国工农业总产值翻两番所需能源的一半要靠节能来解决。实践证明,自动控制技术是一种有效的节能手段。节能工作不应仅着眼于更新工艺 I. Preface According to relevant statistics, by the year 2000, half of the energy required to quadruple the gross industrial and agricultural output of our country depends on energy conservation. Practice has proved that automatic control technology is an effective means of saving energy. Energy-saving work should not only focus on the renewal process