Extending standard functions
A well-built paradigm or design pattern should allow for the extension of standard objects without affecting the object itself. For example, standard objects should consist of other standard objects that can also be used outside of their parent object.
Have a look at the following screenshot:
Figure 8.1 – Example of an extension
Figure 8.1 shows an example of an extension whereby Standard Object Instance 3 has an additional instance of Standard Function Block 1 that is used outside of the normal parent. Because all instances of Standard Object use Standard Function Block 1, and Standard Function Block 1 is in itself a standard, it can be used outside of Standard Object, and data that would normally be passed to Standard Function Block 1 from the Standard Object interface can be passed directly instead.
If the example in Figure 8.1 were to be replicated in Totally Integrated Automation Portal (TIA Portal), the Standard...