The sudden emergence of micro programmable logic controller

Traditional micro plc temperature control module is generally 8 to 64 digital I / O, 1 ~ 4 points analog I / O, small size, can be installed directly in the machine. But now the miniature programmable controller in addition to the above functions, can be compared with the already large programmable controllers on the network functions and man-machine interface functions, this type of micro programmable logic controller manufacturer is currently the fastest fast.

Penetration programmable controller

programmable logical controllers is to adapt the plant control systems and enterprise information management systems increasingly combine trends and adapt to the control level make between different brands of programmable logic controllers, PLC and Distribution effective exchange of data between the requirements of control system. In fact, the realization of multi-tasking system, improve network capabilities, software integration makes the development of information technology, very easy to integrate with a programmable logic controller system.

Programmable Logic Controller Development in China and Countermeasures

The current development of the programmable logic controller (plc) suppliers of the main faces of the three problems. In the rapid development of the international situation, programmable logic controller, with independent intellectual property rights, China has no one on the technical level, can compete internationally programmable controller products, mainly due to the foundation of the whole industry is still There are some gaps, such as aspects of chip manufacturing, mold processing limitation of our development. The second is, in fact, also a question of economic competition competitive level. Now 95% of the domestic market occupied by foreign PLC Programmable Logic Controller, medium and large programmable controller, almost all dominated by several major foreign companies, as China continues to expand the use of field programmable logic controller , the market is growing, however, several major foreign companies almost every year for the market introduction of new products, once people use a new product, they will gradually increase the market price, not our own independent intellectual property rights In economic competition can only be passive. Third, the level of the market order, with the deepening of China's reform and opening up, especially after joining the WTO, China's huge market share greatly attracted foreign companies, they open up the market a wide range of methods are based on an agency sales channels, each company's distributors, system integrators will have dozens, even hundreds of many, resulting in intense competition our distributors, system integrators among these disorderly competition is international large companies divide and rule, get a stable high profits to create the conditions.

Application of Programmable Controller (PLC)

Currently, PLC has been widely applied at home and abroad in metallurgy, petroleum, chemicals, building materials, machinery manufacturing, electric power, automobile, light industry, environmental protection and cultural entertainment and other industries, with the continuous improvement PLC cost performance, its applications continue expand. From the application type, application plc IO module can be broadly summarized as follows:
1. logic control switch
Using PLC basic logic operations, timing, counting and other functions to implement logic control, can replace traditional relay control for stand-alone control, multi-cluster control, automatic production line control, such as: machine tools, injection molding machines, printing machinery, assembly lines , plating lines and elevator control. This is the most basic application PLC, PLC is the most widely used applications.
2. Motion Control
Most PLC has to drag a stepper motor or servo motor single or multi-axis position control module. This feature is widely used in a variety of mechanical equipment, such as machine tools, assembly machinery, robots and other motion control.
3. Process Control
Large and medium-sized plc cpu modules has multi-channel analog I / O modules and PID control functions, and some small-scale PLC also has analog input and output. So PLC enables analog control, and has PID control function PLC may constitute a closed-loop control for process control. This feature has been widely used in boilers, reactors, water, wine, and closed-loop position control and speed control and so on.
4. Data Processing
Modern PLC have math, data transfer, conversion, and table sorting and other functions, can collect, analyze and process the data, while the data via the communication interface is transmitted to other intelligent devices, such as computer numerical control (CNC ) device for processing.
The communication network
PLC communications, including communications, programmable logical controllers systems and general-purpose computer PLC and PLC, PLC and host computer, PLC and other intelligent devices can directly or through the communication processing unit, a conversion unit connected to the communication network to achieve the exchange of information and may constitute "centralized management, decentralized control," the multi-level distributed control system to meet the needs of factory automation (FA) systems development.

Data communication between analog modules

Buffer register (BFM) allocation

FX series PLC basic unit and FX - 4AD, FX - 2da etc. analog module between data communication is performed by the from and to instructions, communication modules plc ,from is basic unit reads data from the FX -- 4AD, FX - 2da instruction, the TOS are from the basic unit writes the data to the FX -- 4AD, FX - 2da instruction. Actually read and write operations are FX - FX, 2DA - 4AD buffer register BFM.

This buffer register consists of 16 registers of 32 bits, plc communication modules ,numbered #31 1 BFM#0.