What is OOP?

OOP is widely misunderstood in the automation field. It is often confusing, as the support of OOP features varies from one PLC brand to another. However, new and increasingly popular PLCs, such as those produced by Beckhoff or Wago, support a very pure form of OOP. There is also prejudice from many in the field to adopt the usage of OOP due to people not understanding the paradigm and the benefits that it offers. Much of the prejudice and misunderstanding stems from the novelty of OOP in the PLC programming realm.

With all that being said, what is OOP? The first step in understanding OOP is to understand what OOP isn’t. Many non-formally trained developers think of OOP as either breaking programs into files, similar to functions, or programming with classes—or, as they are known in IEC 61131-3, function blocks. However, this is a gross simplification and an inaccurate definition of what OOP is. It can be argued that this is where much of the prejudice...