88VK01A-E GJR2312200R1010 ABB

PLC first appeared in the United States in the late 1960s,with the purpose of replacing relays,performing sequential control functions such as logic,timing,and counting,and establishing a flexible program control system.It was officially named and defined in 1976:PLC(Programmable logic Controller)is a special electronic computer for digital control,which uses programmable memory to store instructions,performs functions such as logic,sequence,timing,counting and arithmetic,and uses analog and Components such as digital input and output to control various machinery or work procedures.After more than 30 years of development,PLC has been very mature and perfect,and has powerful computing,processing and data transmission functions.And defined as programmable controller(ProgrammableController PLC).The PLC’s place in the FCS system seems to have been established without much debate.See Figure 3:IEC Recommended Fieldbus Control System Architecture.The PLC hangs on the high-speed bus as a station.Give full play to the advantages of PLC in processing switch quantity.In addition,the auxiliary workshops of power plants,such as water treatment workshop,circulating water workshop,ash and slag removal workshop,coal handling workshop,etc.,the process of these workshops is mostly controlled by sequence.PLC has its unique advantages for sequential control.The control system of the auxiliary workshop should take the PLC that follows the field bus communication protocol or the PLC that can communicate and exchange information with the FCS as the preferred object.

PLC于20世纪60年代末期在美国首先出现，目的是用来取代继电器，执行逻辑、计时、计数等顺序控制功能，建立柔性程序控制系统。1976年正式命名，并给予定义：PLC（ProgrammablelogicController）是一种数字控制专用电子计算机，它使用了可编程序存储器储存指令，执行诸如逻辑、顺序、计时、计数与演算等功能，并通过模拟和数字输入、输出等组件，控制各种机械或工作程序。经过30多年的发展，PLC已十分成熟与完善，并具有强大的运算、处理和数据传输功能。并定义为可编程控制器（ProgrammableController PLC）。PLC在FCS系统中的地位似乎已被确定并无多少争论。参见图3：IEC推荐的现场总线控制系统体系结构。PLC作为一个站挂在高速总线上。充分发挥PLC在处理开关量方面的优势。另外，电厂辅助车间，例如水处理车间、循环水车间、除灰除渣车间、输煤车间等，这些车间的工艺过程多以顺序控制为主。PLC对于顺序控制有其独特的优势。辅助车间的控制系统应以遵循现场总线通讯协议的PLC或能与FCS进行通讯交换信息的PLC为优选对象。