CoDeSys on CCP XS for Bromma Conquip - Research

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Student Joel Ek Supervisor at CC-Systems Fredrik Löwenhielm Dok Nr 1.0 Date 2006-08-08 Rev PA1 Säk klass F Filname Thesis.doc CODESYS ON CCP XS FOR BROMMA CONQUIP 2.2 <strong>CoDeSys</strong> Controlled Developed System (<strong>CoDeSys</strong>) is developed by Smart Software Solutions (3S) and they describe their software as a complete development environment for your PLC. <strong>CoDeSys</strong> implements the standard IEC 61131-3 and 3S is today one the leading manufacture in programming PLC systems. 2.2.1 The IEC 61131 standard The IEC 61131-3 standard is a standard for programming languages that is used in industrial automation, typically to program a PLC. The standard consists of two parts: Common objects and Programming languages [17, 18]. 2.2.1.1 Common objects The common elements define which data types that must exist, how the variables should be declared (input, output and global etc). It also defines that a PLC program is to be build using Programming Organising Units (POU), these POUs are: Program, Function Block and Function. 2.2.1.2 Programming languages The other part defines which languages that should exist in order to follow the standard. They are: Instruction list, Structured Text, Function Block Diagram, Ladder Diagram and Sequence Function Chart. 2.2.2 Languages <strong>CoDeSys</strong> support all the standard languages defined for PLC programming and implements one more, the Continues function chart. Description of the different language in <strong>CoDeSys</strong>: - Instruction List (IL) is a text based language similar to assembler language. - Structured Text (ST) is a text based higher layer programming language. - Function Block Diagram (FBD) allow the user to graphically connect different function blocks, both standardized functions like AND but also own user defined. And in that way create a more complex function. - Ladder Diagram (LD) is the correspondence to ladder logic in the IEC 61131-3 standard and is a graphical language to connect relay and coil. - Sequential Function Chart (SFC) is used for programs that can be divided into step, each step contains some action and the transition to the next step is controlled by a logic condition. - Continues Function Chart (CFC) is similar to FBD, not as fast but more flexible, allowing both continuous connections and change of execution order. 16 (55)
Student Joel Ek Supervisor at CC-Systems Fredrik Löwenhielm Dok Nr 1.0 Date 2006-08-08 Rev PA1 Säk klass F Filname Thesis.doc CODESYS ON CCP XS FOR BROMMA CONQUIP 2.2.3 Program Organization Unit In <strong>CoDeSys</strong> you can create three different types of Program Organization Units (POU); program, function blocks and functions. The different POUs can be written in one of the 6 languages supported. Explanation of the different POUs: - Program: A Program is recognised globally in the project, it can return several values at execution and all values in the program are retained between different executions. It is not possible to make different instances of a program. - Function Block: With Function Block it is possible to make instances 12 where each instance will have a unique name and hold its own structure of variables. It can have several input and output variables, these can be accessed by other POUs whereas the internal variables can not. - Function: A Function can have several inputs but only one output variable. It is not possible to make instances of Functions and a specific input to a Function will always lead to the same output. 2.2.4 Log and error handling 2.2.4.1 Log <strong>CoDeSys</strong> provide a tool called Log, it stores all actions that is performed in online mode and is used for monitoring and trace errors in the program. It is possible to open the log afterward in offline mode and save extracts from the log in external files. The whole Log is during the online session saved in a binary file. The type of action that is saved in the log is chosen before and is of the following categories: - User action: performed by the user and can for instance be ‘Force values’. - Internal action: - Status change: The runtime system has changed status. - Exception: An exception has happened. Each action in the log is described with: type of category, description of action, information about errors occurred during the action, system time, time since start of online session and finally the duration of the action. 2.2.4.2 Alarm configuration Alarm configuration is another tool included in <strong>CoDeSys</strong>, it is used to organize alarm event in a program. These alarms can be errors or other critical process states that the user needs to be notified about. The occurrence of an alarm event can be both visualized and saved to a history file. 12 Copies of the same dataset often used in object oriented programming 17 (55)
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CoDeSys on CCP XS for Bromma Conquip - Research

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