若干个模块，如CPU模块、输入模块、输出模块、电源模块等等。其中各模块功能比较单一，模块的种类却日趋丰富。比如，一些可编程序控制器，除了－些基本的I/O模块外，还有一些特殊功能模块，像温度检测模块、位置检测模块、PID控制模块、通讯模块等等。组合式结构的PLC特点是CPU、输入、输出均为的模块。模块尺寸统一、安装整齐、I/O点选型、安装调试、扩展、方便。叠装式叠装式结构集整体式结构的紧凑、体积小、安装方便和组合式结构的I/O点搭配灵话、安装整齐的优点于一身。它也是由各个单元的组合构成。其特点是CPU自成的基本单元（由CPU和一定的I/O点组成），其它I/O模块为扩展单元。在安装时不用基板，仅用电缆进行单元间的联接，各个单元可以一个个地叠装。使达到配置灵活、体积小巧。SIMATIC S7-200 PLC S7-200 PLC是超小型化的PLC，它适用于各行各业，各种中的自动检测、监测及控制等。S7-200 PLC的强大功能使其无论单机运行，或连成网络都能实现复杂的控制功能。 S7-200PLC可提供4个不同的基本型号与8种CPU可供选择使用。
Several modules, such as CPU module, input module, output module, power module, etc. Among them, the functions of each module are relatively single, but the types of modules are becoming more and more abundant. For example, in addition to some basic i/o modules, some programmable controllers also have some special function modules, such as temperature detection module, position detection module, PID control module, communication module and so on. The PLC with combined structure is characterized by modules with CPU, input and output. The module size is unified, the installation is neat, the i/o point selection, installation and debugging, expansion and convenience. The stackable stackable structure integrates the advantages of compact integral structure, small volume, convenient installation and the combination of i/o points, smart words and neat installation. It is also composed of the combination of various units. It is characterized by the basic unit of CPU (composed of CPU and certain i/o points), and other i/o modules are expansion units. During installation, there is no base plate, and only cables are used for connection between units. Each unit can be stacked one by one. Make the configuration flexible and compact. SIMATIC S7-200 PLC S7-200 PLC is a super miniaturized PLC, which is suitable for automatic detection, monitoring and control in all walks of life. The powerful function of S7-200 PLC enables it to realize complex control functions whether it is running alone or connected into a network. S7-200PLC can provide 4 different basic models and 8 kinds of CPUs for selection.