The controller is the control center in the automatic control system.The controller of HCS adopts typical computer structure like PLC,mainly including processor,memory,I/O interface,and communication interface.The frame of the HCS controller follows the frame size structure of the traditional PLC,so the volume is much smaller than that of the DCS.Although the HCS controller is very similar to the PLC in terms of size and shape,it is by no means a simple copy of the PLC.The HCS controller performs closed-loop and sequential control in the process control,and can be competent for the process control tasks undertaken by the DCS.The HCS controller adopts a modular structure.The processor module,local I/O module,communication interface module,etc.are all inserted into the same frame and connected through the data bus to realize”soft wiring”.In addition,remote I/O modules can be extended through the N2 network./O module.
Each HCS can support multiple controllers,and each controller can support up to hundreds of control loops.In this way,a larger control system can be composed of HCS,and the control is decentralized.Such as ProcessLogix control system can support up to 16 controllers,each controller can support 125 to 150 control loops.
控制器为自动控制系统中的控制中枢。HCS的控制器与PLC一样采用了典型的计算机结构，主要包括处理器、内存、I/O接口，外加通讯接口。HCS控制器的框架沿袭了传统PLC的框架尺寸结构，因而体积比DCS小得多。虽然从尺寸与外形上看，HCS控制器与PLC极其相似，但它绝不是PLC的简单翻版。HCS控制器在过程控制中执行闭环及顺序控制，能胜任DCS所承担的过程控制任务。HCS控制器采用模块化结构形式，处理器模块、本地I/O模块、通讯接口模块等均插入同一框架中，通过数据总线相连，实现“软接线”，另外，通过N2网还可扩展远程I/O模块。
每个HCS可支持多个控制器，而每个控制器又可支持多达上百个控制回路。这样由HCS便可组成较大型的控制系统，且控制是分散的。如ProcessLogix控制系统最多可支持16个控制器，每个控制器可支持125～150个控制回路。
