Analysis of Application of PLC Technology in Industrial Automation

With the continuous advancement of computer technology and electronic communication technology, PLC technology has also been rapidly developed. It is widely used in the field of industrial automation and plays an important role in China's industrial modernization. This article introduces the PLC technology briefly, analyzes the application of PLC technology in industrial automation, and points out some problems that need to be paid attention to in the application process. It is hoped that it will promote the further application and development of PLC technology in the field of industrial automation.

PLC technology is a kind of digital computing and manipulation technology. It consists of several modules: computer technology, automatic control technology, and communication technology. It has the characteristics of simple operation, strong anti-interference ability, and rich functions. At present, the level of development of PLC technology and the degree of industrialization and application have become a measure of the country’s industrial modernization. With the continuous improvement of the PLC function and the continuous popularization of application, the development of industrial automation is increasingly dependent on the development of PLC technology. Strengthening the research and discussion of PLC technology is of great significance for the realization of industrial modernization in China.

Analysis of Application of PLC Technology in Industrial Automation

1.1 Switch Control

PLC switch control in industrial automation control is mainly reflected in the following points:

PLC was initially used as a product to replace relays. It integrated switch control functions. Compared with relays, PLC switches have the characteristics of simple circuit connection, sensitive response, simple operation, easy maintenance, and high reliability.

The controllability of the PLC switch is very powerful. It can control as many as a dozen or more nodes, thousands or even tens of thousands, greatly saving the human resources, improving the time utilization, and greatly improving the system quality. PLC switch design should be based on the PLC system control sequence and design ideas, and then draw an intuitive ladder diagram of the control system, and the use of analog simulation operation to detect the state of the system, to ensure the standardization of the system design and effectiveness.

The logic control mode of PLC switch is flexible and can be switched between combination and timing, instant and delay, count and uncount, fixed and random.

1.2 Process and Motion Control

PLC process control includes the control of discrete process and the control of continuous process. PLC can flexibly change the control algorithm so that the parameters such as temperature, flow, liquid level, pressure, and composition of the system can be transformed in strict accordance with the requirements of the system. The needs of industrial production, this type of PLC mainly for chemical, smelting, heat treatment and boilers and other fields.

PLC motion control is the trajectory control of processing equipment, including circular motion control and linear motion control. It is worth mentioning that PLC can perform pulse-based device control. Because the pulse control only produces small displacement, the control accuracy of PLc is achieved. A very high level. At this stage, this type of PLC motion control is mainly aimed at machines, elevators, and lathes.

1.3 Analog and centralized control

The PLC control system has different combination modules according to different control objects, including a central processing module, an input/output module, a logic operation module, a communication module, and the like. Through the combined application of each module, the control of the system is targeted. Through the simulation of the Plc, the accuracy of the system for process control is greatly improved, and the process of temperature increase, temperature decrease, and heat preservation of the system are strictly executed according to the plan, which fully satisfies the control design and requirements of the industrial process.

In addition, PLC has a powerful centralized control function, in addition to meeting industrial automation control, can also achieve its own good control, LPC by detecting the logical relationship between the input and output signals and the intermediate memory module, timely diagnosis and indication of its own fault, so as to achieve equipment Failure analysis and warning.

1.4 Motor Frequency Control

PLC is very rich in the motor frequency control instructions, and can be combined with the inverter to complete the motor speed control. Take P恻 as an example, a voltage smoothing circuit is usually added between LPC and P恻, and the motor rotation speed is controlled by the value of t in the P恻 instruction. The rotation speed is positively correlated with the value of t. When the ratio of the rotation number to the value of t is greater than 1 o The motor will increase the speed accordingly.

Analysis of Application of PLC Technology in Industrial Automation

As a direct guarantee of industrial automation, the stability of PLC is of great significance to production. For the moment, PLC technology is relatively mature and has good stability. However, PLC has a wide range of applications and often faces some comparisons. In a bad working environment, we must fully consider the influence of negative factors such as temperature, humidity, vibration, and interference, strengthen design and protection, and create a favorable working environment for the PLC system.

2.1 Temperature Limit

PLC has certain requirements for the working environment temperature, generally limited to 0 °C ~ 55 °C, therefore, PLC in the installation process should fully consider the good heat dissipation factors, try to avoid sunlight or other heat sources, can not be placed directly on other heating equipment Below. For the working environment where the temperature is higher and the design requirements are exceeded, install ventilation cooling or cooling equipment and reserve enough space for heat dissipation to effectively control its operating temperature and ensure the stable operation of the PLC system.

2.2 Humidity limit

Some of the components in the LPC system are sensitive to the humidity of the environment. If the humidity is too high, the insulation performance of the component will be affected, which will affect the stable operation of the system or lead to component failure. Therefore, the working environment humidity of the PLC system must be controlled properly. Can't exceed 8590.

2.3 Vibration Control

For the PLC system, strong vibration is a very harmful factor, especially when the frequency is between 10 and 55 Hz for a long period of time. It should be avoided as much as possible. For some difficult to avoid vibration environments, it is necessary to adopt shock absorption. Rubber and other shock absorption measures to prevent the system from being damaged by vibration.