In the PC and programming world, the phrase OOP stands for Object Oriented Programming, referring to coding standards based around re-usable objects, with descriptions of ‘Classes’, including ‘Attributes’ and ‘Characteristics’ and ‘Methods’. It refers to methodology for programming in computer languages such as C, C++, and it means concentrating on objects to represent the real-world items, and reusable code libraries to access and manipulate the objects. There is a good explanation of it all here
https://codeinstitute.net/ie/blog/object-oriented-programming/
In Accord, the process model configuration is implemented in Designer and the OOP representation might be considered as
| Class | Valve, Analog Device, Program, Step | |
| Attributes | Error, at Min Range, Active, Time Remaining | |
| Characteristic | Delay on Time Setpoint, Max Range, Number of Steps, | |
| Object | XV1234, P0567 VSD, Filling Program, Drain Step | |
| Method | the code library that operates on the objects in PLC or Emulator. |
OOP considers data for objects in classes and the code for the class together but Accord doesn’t require any coding at designer level so we are just talking about data. The data generated is actually worked on in Emulator or PLC and the Method aspect could be considered as the run-time library.
Further principles in OOP, and the consideration in Accord are:
Encapsulation: – the hiding of some internal details of an object, only making visible the data necessary for interaction, to protect the object’s data and ensure consistency. Accord certainly works like this, in that only configuration or selection data is exposed for the user.
Inheritance: allowing classes to get properties and methods from other classes, to allow for code reuse and relationships between objects. Accord has at least one instance of this in the Designer.
Polymorphism: allowing objects of different classes to be treated in common manner to promote flexible usage. Accord does list different classes of objects in common lists, in Interlocks and other enablers. Again, we just use it in data and references, and not for code.
Abstraction: means that only the important aspects are shown, and the background working is hidden. This is true of Designer, the unnecessary aspects are not presented to the user.