Wednesday, December 29, 2010
Weak current College】 【PLC programming language profile】.
<br> <br> Programmable controller programming language: <br> In the programmable controller in a variety of programming languages, they are the ladder diagram language, Boolean mnemonics language, function table diagram language, function module diagram language and structured statement description language ., etc. Ladder diagram language and Boolean mnemonics language is basic programming language, it usually consists of a series of instructions, use these instructions to complete the most simple control functions, for example, instead of relays, counters, timers, complete sequence control and .logic control, extended or enhanced instruction sets, they can perform other basic operations. Function table diagram language and statement description language is a high-level programming language, it may, as necessary to carry out more effective operation, for example, analog control, .data manipulation, reports newspaper printing and other basic programming language for the function could not be completed. Function modules using function module graph language chart format, through soft connection complete the required control function, it not only in the programmable controller has been widely used in .the distributed control system for programming and configuration is also often used, because it has a connection to a convenient, easy operation, easy to learn and so on, for the majority of engineering design and application staff favorite. <br> According to the application .scope, kebianchengqi programming language can be used in combination, the commonly used programming languages are: <br> Ladder diagram programming language <br> Boolean mnemonics programming language (statement) <br> Function table figure programming language <br> Function module graph programming .language <br> Structured statement describes programming language <br> Ladder diagram and structured statement describes programming language <br> Boolean mnemonics and function table figure programming language <br> Boolean mnemonics and structured statement describes programming language <br> 1, ladder diagram ( .Ladder Diagram) programming language <br> Ladder diagram programming language is the ladder diagram graphic symbols to describe the process of a programming language. Use of ladder diagram programming language, is available in the form of ladder diagram. The programming language used to describe a .causal relationship between the occurrence conditions and results. Each step is a causal relationship. In the cascade, describes the conditions that the event occurred on the left, the results of the said event occurred. <br> Ladder diagram programming language is the most common .of a programming language. It originates from the relay logic control system description. In the field of industrial process control, electrical technicians on technical relay logic control, therefore, more familiar from this logic control technology development of ladder diagram was welcomed, and has been .widely used. Ladder diagram programming language is characterized by: <br> (1) and electrical operation principle figure corresponds with intuitive and responsive; <br> (2) and the original relay logic control technology, electrical technician, easy-to-telecentres .and learning; <br> (3) and the original relay logic control technology is the difference, ladder diagram of energy flow (Power FLow) is not the actual significance of current internal relay is not the actual existence of the relay, as a result ., applications, and the original relay logic control technology of the concept of discrimination; <br> (4) and Boolean mnemonics programming languages have a one-to-one relationship, to facilitate mutual transformations of the inspections and procedures. <br> 2 ., Boolean mnemonics (Boolean Mnemonic) programming language <br> Boolean mnemonics programming language is used Boolean mnemonics to describe the process of a programming language. Boolean mnemonics on programming languages and computer Assembly language is very similar to the use of Boolean mnemonics to indicate operation .capabilities. <br> Boolean mnemonics programming language has the following characteristics: <br> (1) use of mnemonics to represent operations functionality with easy to remember, easy to the characteristics of the telecentres; <br> (2), programmer .keyboard using mnemonic representation, with easy-to-use features, without computer programming and design of occasions; <br> (3) and ladder diagram have a one-to-one relationship. Its characteristics and ladder diagram language Basic. < .br> Figure 3, the function table (Sepuential Function Chart) programming language <br> Function table figure programming language is used to describe a feature table figure is a programming language. It was in recent years developed a programming language. Functional description of the .table, the control system is divided into several subsystems starting from function, so that the system has a specific meaning for designers and operators communicate design ideas, easy to program design and check of the Division of labour. Function table figure programming language is characterized by .: <br> (1) to function as the main line, clarity, ease of understanding of the program operation and communication; <br> (2) the procedures for large, Division of design with a more flexible program structure, saves programming time .and debugging time; <br> (3) commonly used in large scale school system, the program relationship more complex situations; <br> (4) only in the active step command and operation is performed on the active step after the conversion is scanned ., so that the whole process of scanning time than other programming of a program to greatly reduce the scanning time. <br> Function table figure comes from petley (Petri) network, because it has a graphical representation, be relatively simple and clearly .describe the concurrent systems and complex system of all phenomena, and the system is like a deadlock, insecurity, and other anomalies for analysis and modeling, based on the model of programming directly, therefore, has been the application of article pan. In recent years ., the launch of the programmable controller and small distributed control system also provides a function table graph description language for programming software. About petley (Petri) network of some basic overviewRead it later, I had the opportunity to introduce to you, to help you further .functional table figure. <br> 4. functional modules (Function Block) programming language <br> Function module graph programming language is expressed using function modules with the function module, the different functional modules with different functions. It has several inputs and .outputs, by soft connection, connect to the other Terminal, complete the required control operation or control function. Function module can be divided into different types, in the same type, or you may be function parameters of the function or application scope vary, for .example, input the quantity, the type of the input signal and so different that it's using a different scope. As a result of the flexible connection of function modules and functional modules and external terminals for the connection, the control scheme changes, signal connection replaced ., and so you can easily implement. Function module graph programming language is characterized by: <br> (1) the function module as a unit, starting from the control function, control scheme of analysis and understanding easier; <br> (2) .functional module is a graphical way to describe the feature, it's intuitive greatly facilitates the design of programming and configuration, a better ease of operation; <br> (3) on the control of larger, more complex control systems, as recorded in the control .function can be more clearly, therefore, programming and configuration time can be shortened, debugging time can be reduced; <br> (4) because each function module takes a certain amount of program memory, execution of the function module requires a certain amount of .execution time, therefore, this design language in large and medium-sized plc and DCs programming and configuration, only to be used in. <br> 5. structured statement (Structured Text) description of the programming language <br> Structured statement .describes programming language is a structured description statement to describe the process of a programming language. It is a language similar to advanced programming language. In large and medium-sized of PLC systems, often using structured statement describes programming language to describe the variables in the .control system. It can also be used for distributed control system for programming and configuration. <br> Structured statement describes programming language uses the computer's description statement to describe the system variables between the various operational relationship, complete the required feature or operation. .Most manufacturers use statement describes programming language and BASIC language, PASCAL language or C language, similar to a high-level language, but for the sake of convenience, the expression in the statement and the statement of the types of methods are simplified. .<br> Structured programming language has the following characteristics: <br> (1) a high level language for programming, you can accomplish more complex control operations; <br> (2) need to have certain computer advanced programming language knowledge and programming skills ., programming staff skill requirements are higher, ordinary electrical officers could not be completed. <br> (3) the intuitive and easy operation of poor performance; <br> (4) are used to using function module in another language is more difficult to .achieve in a number of control functions. <br> Part of the programmable controller manufacturer provides users with a simple structured programming language, and mnemonic programming language similar to that of the number of steps with some restrictions, at the same time, provides .programmable controller interface or communication connection program presentation to the user application provides room for expansion. <br>.