【正文】 on between issues. During the system is the development of a number of new features, using a 32 or 64bit microprocessor, and a powerful workstations and enhanced the sequence control, volume control, the system can acmodate industrial PC and PLC。 introduction of the expert system, process control and other senior adaptive control function. Its products include Foxbor pany representative I / A Series intelligent control system, ABBBailey INFI 90, ABB pany Freelance 2020, RTP pany RTP 2020/2200 HCS (Mixed Control System), and Yokogawa XL mXL, Honeywell Corporation TDC3000 LCN / VCNPM and Siemens PCS 7 systems. 2. New characteristics and new development (1) Open to the DCS system to develop in the direction of CIMS Along with the standard munication work and the development of fieldbus technology, a multilevel munications work DCS is the progressive realization of the full liberalization. The new system is the adoption of the ISO OSI model, the munication protocol to meet MAP / TOP or IEEE standards. In a backbone work, widely used MAP agreement or ISO / OSI model。 dedicated programming method used to achieve the X Window, voice recognition, etc., in order to industrial automation users provide more flexibility in the application of the operator interface. (6) intelligent sensors and other digital equipment to enter the scene of DCS At present, the industrial process control automation pany has introduced a large number of microprocessors, have both analog and digital signal output, and digital munication capabilities of intelligent field instrument. DCS manufacturers are using a variety of methods of the digital field devices integrated into its own system. Honeywell IACD such as twoway munication system for intelligent transmitter and TDC3000 process controller connections and other ponents。s first programmable controller. Early separation from the programmable controller ponents and small and mediumsized integrated circuit ponent, the main function previously performed by the relay is pleted sequence control, such as timing. The early 1970s, small size, strong function and cheaper microprocessors used PLC, makes the PLC function has been enhanced significantly. In terms of hardware, in addition to maintaining its original switch modules, has also increased the simulation module, remote I / O modules and special function modules all. In terms of software, easy to use PLC Electric staff in the ladder diagram programming language, in addition — 3 — to maintaining the original logic functions, has also increased the arithmetic operations, data processing and transmission, munications and selfdiagnostic capabilities. In the 198039。 Foxbro panies addition to its own digital equipment integrated into the scene intelligent I / O system, also provides more than 60 other manufacturers, connecting doors connector. Fieldbus standard, from the bottomup equipment to achieve the interconnection of different manufacturers, with the current technology development trend. At present, the development of fieldbus standard has been a high degree of international attention, is integrated industrial automation control system indispensable ponent. With the — 13 — standardization of fieldbus munication technology development, the more intelligent DCS and control will shift downward, decentralized control equipment at the field level. They will DCS in the diagnosis and treatment provide a better platform, which enables more advanced DCS to open forms. (7) DCS further acmodate industrial PC and PLC Industrial PC and PLC equipment as the DCS is now very mon. DCS overwhelming majority of manufacturers has been providing industrial PC, PLC to DCS work connected to the hardware interface and application software. Industrial PC can make use of touchscreen and CRT window, a menudriven approach may be to establish control strategy can also be used to achieve a plug on the motherboard and external munication. Through appropriate software and hardware interfaces, industrial PC with DCS in the process of connecting loop controller for loop control graphics. DCS industrial use as a PC operating station, programming terminals, surveillance, Taiwan, workstations, such as ABBPele, panies such as DCS Feixieer few years ago and the IBM PC patible, DEC Professional, as well as 300 personal puters, etc. used for system configuration, monitoring, programming, and other tasks. Apart from some manufacturers developed a series of interface ponents and software, industrial PC as a DCS operator stations and other tasks, but also by thirdparty manufacturers such as OnSpec, and other process control packages. The relationship between the PLC and DCS is not only bine, and pete. Most are now bining DCS ladder logic programming technology, all PLC increases the simulation module to deal with the continuous production process. PLC through structural improvements, munications and working capacity and control functions to increase and the introduction of similar DCS operator station, with monitoring puter operator interface. DCS also continuously enhance and batch processing capabilities, a smallscale, highfunctional, modular direction. Thus DCS and PLC are gradually move closer, the two boundaries bee increasingly blurred. They are functional and application of mutual peration and integration. Thus, in many applications, it is difficult to distinguish between what is the PLC, which is the DCS. DCS are generally of the PLC interface can be connected to the PLC in the DCS. At present, a PLCbased DCS developed very quickly, discrete manufacturing and — 14 — process industries tend to use hybrid control strategy PLC / DCS. Some of the same chassis system will be continuous control and PLC logic function together, not a separate PLC systems, such as the U