一、前言Ⅰ系列仪表是日本横河公司在七十年代初投入市埸的一套采用集成电路的电动单元组合仪表。它作为常规自控仪表被广泛地应用在我国一些大型化工、冶金、化肥等成套进口设备中,并在实际应用中得到用户的好评。现在,Ⅰ系列仪表已由西安仪表厂技术引进,并已投入成批生产,随着生产量的增加,将更加普遍地应用在我国工业生产的各个领域。Ⅰ系列仪表根据其供电方式不同,可以分为两大类型:(1) 直流24V电源集中供电型。以下称为Ⅰ—24VDC系统。(2) 每台仪表各自带有独立电源单元的交流电源供电型。以下 I. Preface Ⅰ series instrument is Yokogawa in Japan in the early seventies into the market a set of integrated circuits using electric unit combination meter. It is widely used in some large-scale chemical, metallurgy, chemical fertilizer and other imported equipment in our country as a routine self-controlled instrument, and has been well received by users in practical applications. Now, Ⅰ series instruments have been introduced by Xi’an Instrument Factory Technology and have been put into mass production, with the increase in production, will be more commonly used in all areas of industrial production in China. Ⅰ series instruments according to their different power supply can be divided into two types: (1) DC 24V power supply centralized type. The following is called I-24VDC system. (2) Each instrument has its own power supply unit AC power supply type. the following