The use of programmable logic controller (PLC) almost covers all walks of life in the field of industrial control in China. Especially after the microprocessor was born, the programmable logic controller was pushed to another climax. Since then, producers of PLC have sprung up, and among these manufacturers, Siemens is undoubtedly a pioneer.
Germany’s SIEMENS (SIEMENS) company is the world’s leading companies in the field of electrical engineering, the company produces the application of programmable controller in our country is quite widespread, in the field of metallurgy, chemical industry, printing line, are used. SIEMENS PLC products include LOGO, s7-200, s7-300, s7-400, s7-1200, etc. Siemens S7 series PLC is small, fast and standardized, with the ability of network communication, stronger function and high reliability. Siemens S7 series PLC products can be divided into micro PLC (such as s7-200), small performance requirements of PLC (such as s7-300) and PLC (such as s7-400) with high performance requirements.
Siemens PLC can be divided into minicomputers, medium-sized machines and mainframes according to the control scale. The PLC control point of Siemens minicomputer is generally within 256 points, which is suitable for control of single machine or small system. Siemens PLC control points of medium-sized machine is generally not more than 2048 points, of equipment can be used to control directly, can also for multiple monitor to the next level of programmable controller, it is suitable for control of the control system of medium or large. Siemens PLC control mainframe is generally not more than 2048 points, can not only can accomplish more complex arithmetic complex matrix operations, but also to direct control of equipment, can also for multiple monitoring programmable controller to the next level.
Siemens PLC can be divided into low gear, middle and high – grade machine according to the control performance. Siemens PLC has a low working speed and fewer input and output modules. Siemens PLC has strong control function and high operation ability. Siemens PLC has powerful control function and powerful computing power.
Siemens PLC according to structure can be divided into integral, modular, folding. The PLC features of Siemens monolithic structure are very compact, small volume, low cost and convenient installation. The PLC features of Siemens composite structure are independent modules of CPU, input and output. The PLC features of Siemens stacking are the basic unit of cpus (consisting of CPU and certain I/O points), and other I/O modules are extension units.
SIMATIC series PLC, born in 1958, has experienced C3,S3,S5 and S7 series. It has become a very popular programmable controller. The first product was SIMATIC S3, which was launched in 1975. It was actually a binary controller with a simple operational interface. In 1979, the S3 system was replaced by the S5, which used a wide range of microprocessors and added many features. In 1994, the S7 series was born, and it has the advantages of more internationalization, higher performance rating, smaller installation space, better WINDOWS user interface and so on. Since the initial development, Siemens S3 and S5 series PLC have gradually withdrawn from the market and ceased production, while S7 series PLC developed into the control core of Siemens automation system. If the automatic control system is likened to one person, the S7 series PLC is the human heart. Thus it can be seen that it is important in automatic control system.
Siemens PLC s7-200 is a super miniaturized PLC, which can be used for automatic detection, monitoring and control in all kinds of fields. The powerful functions of Siemens PLC s7-200 make it possible to achieve complex control functions, whether single or connected. S7-200 Siemens PLC can provide 4 different basic models and 8 types of CPU to choose from.
Siemens PLC s7-300 is a modular small PLC system which can meet the application of medium performance requirements. A wide array of individual modules can be combined to form systems of different requirements. Compared with s7-200 Siemens PLC, s7-300 Siemens PLC adopts modular structure and has the instruction operation speed of high speed (0.6 ~ 0.1mu s). The floating point arithmetic is used to realize more complex arithmetic operations. A software tool with standard user interface is convenient for users to assign values to all modules. Convenient man-machine interface services have been integrated into the s7-300 operating system, and the programming requirements of man-machine dialogue have been greatly reduced. The SIMATIC man-machine interface (HMI) obtained data from Siemens PLC s7-300, and s7-300 Siemens PLC transmitted these data according to the refresh rate specified by the user. Siemens s7-300 operating system automatically handles data transmission; The intelligent diagnostic system of cpus continuously monitors the function of the system, records errors and special system events (e.g., timeout, module replacement, etc.); Multi-level password protection enables users to protect their technical secrets effectively and effectively to prevent unauthorized copying and modification; Siemens S7-300 PLC is equipped with operating mode selection switch, operating mode selection switch like keys can be pulled up, when the keys out, can’t change the way of operation, so that it can prevent illegal deleted or rewrite the user program. With strong communication function, s7-300 Siemens PLC can provide the communication configuration function through the user interface of program software Step 7, which makes the configuration very easy and simple. At the same time, s7-300 Siemens PLC has many different communication interfaces, and connects the as-i bus interface and the industrial Ethernet bus system through a variety of communication processors. Communication system used by serial communication processors to connect point to point; The multi-point interface (MPI) is integrated into the CPU for automatic control systems such as connecting the programmer, PC, human-machine interface system and other SIMATIC S7/M7/ C7.
Siemens PLC s7-400 is a programmable controller for medium and high grade performance range. Siemens S7-400 PLC adopts modular fanless design, reliable and durable, as well as a variety of levels (function gradually upgrade) of CPU, and is equipped with a variety of general function template, the user can according to need different dedicated system. When the control system is scaled up or upgraded, you can upgrade and fully meet the requirements as long as you add some templates appropriately.
Siemens PLC power supply with card without battery; There are also batteries with CARDS. Programs exist in the MMC card, if there is no memory card, need battery saving program, replace the battery when it is important to note that under the condition of charged, remove the old battery, then put the new battery change.