What are the common programming languages of PLC?

PLC commonly used programming language:

There are many programming languages in the programmable controller, they are ladder diagram language, Boolean mnemonic language, function chart language, function module diagram language and structured statement description language, etc. Ladder language and Boolean mnemonic language is the basic programming language, which is usually composed of a series of instructions, which can accomplish most simple control functions, for example, instead of relays, counters, timer complete sequence control and logic control, by extending or enhancing the instruction set, they can also perform other basic operations. The functional table diagram language and statement Description Language are advanced programming languages that perform more efficient operations as needed, such as control of analog quantities, manipulation of data, reporting of reports, and functions that cannot be completed by other basic program design languages. The function module diagram language uses the Function module diagram form, through the soft connection way completes the required control function, it not only obtains the widespread application in the programmable controller, in the distributed control system programming and the configuration also often is used, because it has the connection convenient, the operation is simple, easy to grasp and so on characteristic, For the vast number of engineering and application staff love.

According to the application scope of the programmable device, the programming language can be used in combination, the common programming language is: Ladder diagram programming language, Boolean mnemonic programming language (statement table), function Chart programming language, functional module diagram programming language, structured statement description programming language, Ladder diagram and structured statement Description programming language, Boolean mnemonic and functional table diagram programming language, Boolean mnemonic and structured statement description programming language.

1. Ladder diagram (Ladder Diagram) programming language

Ladder diagram programming language is a programming language which uses the graphical symbols of ladder diagram to describe the program. Using ladder diagram programming language, the program uses ladder diagram form description. This programming language uses causality to describe the conditions and results of event occurrence. Each rung is a causal relationship. In the cascade, the condition that describes the occurrence of the event is expressed on the left, and the result of the event is indicated behind. Ladder diagram programming language is one of the most commonly used programming languages. It is derived from the description of the relay logic control system. In the field of industrial process Control, electrical technicians are familiar with the logic control technology of relay, so the ladder diagram developed by this logic control technology is welcomed and widely used.

The features of the ladder Diagram programming language are:

(1) corresponding to the schematic diagram of electrical operation, with the visual and correspondence;

(2) Consistent with the original logic control technology of relay, it is easy to hold and study for electrical technician;

(3) with the original relay logic control technology, the difference is that the ladder diagram of the energy flow (Power flow) is not the actual meaning of the current, the internal relay is not the actual relay, therefore, the use of the original relay logic control technology related to the concept of different treatment;

(4) with the Boolean mnemonic programming language has one by one correspondence, facilitates the mutual conversion and the procedure examination.

2. Boolean mnemonic (Boolean mnemonic) programming language

Boolean mnemonic programming language is a programming language for describing programs with Boolean mnemonics. Boolean mnemonic programming language is very similar to the assembly language in computer, using Boolean mnemonic to denote operation function.

The Boolean mnemonic programming language has the following characteristics:

(1) The use of mnemonics to denote the operation function, with easy to remember, easy to hold the characteristics;

(2) on the keyboard of the process device using mnemonic notation, with ease of operation characteristics, can be used in the absence of computer programming design;

(3) with ladder diagram has one by one correspondence. Its characteristics and ladder diagram language basically similar.

3. Functional chart (sepuential function chart) programming language

Functional Chart programming language is a programming language for describing programs using a functional table diagram. It is a programming language developed in recent years. Using the description of the functional table diagram, the control system is divided into several subsystems, starting from the function, so that the operation of the system has a clear meaning, easy to design staff and operators to design ideas of communication, easy to design the division of the program and check debugging.

The features of the functional chart programming language are:

(1) function as the main line, well-organized, easy to understand and communicate the operation of the program;

(2) for large-scale procedures, can be divided into design, using a more flexible program structure, can save the design time and commissioning time;

(3) often used in the scale of the system, the procedural relationship is more complex occasions;

(4) Only in the active step of the command and operation is performed, the activity after the conversion of the scan, therefore, the entire program scanning time than other programs programmed scanning time is much shorter.

The function chart is derived from the Petrelli (Petri) NET, because it has the graphic expression way, can describe the concurrency system and the complex system all phenomena more simply and clearly, and can analyze and model the abnormal phenomena such as deadlock, insecurity and so on, which can be programmed directly on the basis of the model, so the application of the text pan is obtained. In recent years, the programmable controller and the small-scale distributed control system have been provided with the function table Diagram Description Language programming software. On some basic concepts of the Petrelli (Petri) Nets, I will introduce them to you later, in order to facilitate further understanding of the functional chart.

4. function Block Diagram programming language

Functional Module Diagram programming language is the function module to represent the function of the module, different function modules have different functions. It has a number of inputs and outputs, through a soft connection, respectively, connected to the other terminals required to complete the required control operations or control functions. Functional modules can be divided into different types, in the same type, may also be due to functional parameters of different functions or the scope of application, for example, the number of inputs, the type of input signal, etc., so that its scope of use is different. As a result of the soft connection between the function module and the function module and the external terminal connection, so the control scheme changes, signal connection replacement and other operations can be easily implemented.

The features of the functional module diagram programming language are:

(1) The function module, starting from the control function, makes the control scheme analysis and understanding easier;

(2) Function module is a graphical method of describing the function, its intuitive nature greatly facilitates the design of the programming and configuration, there is a better easy to operate;

(3) The control of large scale, the control of the relationship between the record system, because the relationship between the control function can be clearly expressed, therefore, the programming and configuration time can be shortened, debugging time can also be reduced;

(4) Since each function module needs to occupy a certain amount of program memory, the implementation of the function module requires a certain amount of execution time, therefore, this design language in large and medium-sized programmable controller and distributed control system programming and configuration is adopted.

5. Structured statement (structured Text) description of the programming language

Structured Statement Description programming language is a programming language for describing programs with structured descriptive statements. It is a programming language similar to a high-level language. In the large and medium-sized programmable controller system, structured statement description programming language is often used to describe the relationship of each variable in the control system. It is also used in the programming and configuration of distributed control systems.

The structured statement Description programming language uses computer descriptive statements to describe the various operational relationships between variables in the system, and to accomplish the required functions or operations. Most manufacturers use the statement Description programming language similar to the basic language, Pascal language or C language and other high-level language, but for the convenience of application, the expression of statements and the types of statements are simplified.

Structured programming languages have the following characteristics:

(1) using high-level language programming, can complete more complex control operations;

(2) need to have a certain high-level computer programming language knowledge and programming skills, the skills of the programmer of high demand, ordinary electrical personnel can not be completed.

(3) Poor performance such as intuitive and operability;

(4) It is often used to implement some control functions that are more difficult to implement in other languages such as functional modules. The manufacturers of some programmable controllers provide users with simple and structured programming language, which is similar to mnemonic programming language, has certain restrictions on the steps of the program, and provides an interface between the programmable controller and the programming method of the Communication Connection program, which provides an extension for the user's application.

An automatic training to adapt to market trends, in the electrical Training industry excellence, deep-rooted, honest school, casting brand, in order to create "China's most influential professional electrical training" as its mission, and constantly strive to export more outstanding technical personnel for China's electrical market, to promote the development of China's electrical automation industry innovation. One sail automation to build China's actual combat brand.

Sail PLC Training year-end big discount! Register now for Mitsubishi + Siemens advanced classes, gift case classes + mechanical CAD or SolidWorks courses +eplan
The electrical drawing course has a total of 20 places to stop! This month, the top 10 students can also enjoy a discount of 980 yuan! And then give the programming cable a line! Plan
Next year to learn the small partners can also register now, next year to learn! There is no limit to learning time after registration! Permanent effect! For more information, please contact: Teacher Liu 136-32-53-94-88

What are the common programming languages of PLC?