I have created a class (FB with Methods and Properties).

I would like one the variables within this class to be another class (FB with Methods and Properties).

But when I try to use F2 to enter a specific method or property of the instance within the instance, I cannot find the instance within.

I would like to access the elements something like:
ourLargeSystem[3].mySubSystem.mySubInt := 4;

This doesn't seem to work. I get an error that 'mySubSystem' is not an input of largeSystem.

Here's some pseudo-code. What I am doing wrong.

Thanks for any ideas. I must be missing something.
JP

GlobalVariables
ourLargeSystems : ARRRAY[1..10] OF largeSystem;
END Global Variables

FB largeSystem
VAR
_myInt : INT;
_myReal : REAL;
mySubSystem : subSystem

END_VAR
etc... with Methods and Properties

FB subSystem
VAR
_mySubInt : INT;
END_VAR
etc. with Methods and Properties

Originally created by: scott_cunningham

Your problem is scope of variables. Items defined as VARs of FBs are not available outside of the FB.

If you want to acces variables outside fb you habe to declare its as var_input.

But is a best practice to acces its via methotds (get set).

For true OOP you should be able to make the new fb with the extends or implements setting and then also use the super command too see the following as a good example. https://infosys.beckhoff.com/english.ph ... 9.html&id=

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Josep M. Rams hat geschrieben:
If you want to acces variables outside fb you habe to declare its as var_input.
But is a best practice to acces its via methotds (get set).

Thank you. That was the issue. I plan to use the methods for the member instances, but I could not "see" the member methods and properties until I moved the variable to VAR_INPUT.

Thanks.
jcp

Originally created by: scott_cunningham

You can also define the object as a VAR in your function block and then create a property for your function block that returns a reference to the object. Only create the get - delete the set. You can then have access to the internal object's methods and properties.

Originally created by: scott_cunningham

Here is a screen shot of your solution using a property and REFERENCE TO. You have access to all of subsystem's methods and properties. You do not have access to subsystem's internal VARs like mySubInt (the only debugger does, however). I used the property CurrentCount for that. (You could have a Set function for CurrentCount, and then you basically have access to your internal var).