STRUCTs in a GVL

2021-03-27T12:39:19.303000Z

"In the other program you can nest structures in data block/other structures, and in Codesys you can't do it."

To nuance, the IEC61131-3 norm (which CODESYS follows really well) does not allow type definition and instancing of DUT data types in a single go. If you wish to read up on this I can recommend this book: https://link.springer.com/chapter/10.1007%2F978-3-642-12015-2_8

STRUCTs in a GVL

2021-03-27T05:14:45.255000Z

Create sub STRUCT

TYPE sSub :
STRUCT
    Value   : INT;
END_STRUCT
END_TYPE

Create main STRUCT

TYPE sMain :
STRUCT
    Value   : INT;
    SubVal  : sSub;
END_STRUCT
END_TYPE

Declare and Initialize in GVL

VAR_GLOBAL
    NestedStruct    : sMain := (value:=1, SubVal:=(Value:=2));
END_VAR

Access any variable declared in GVL from a program attached
to a task, otherwise compiler doesn't bother to compile it.

Main_PROG
    VAR
        Val : INT;
    END_VAR

    VAL := NestedStruct.SubVal.Value;
END

Compile and go Online to see GVL data

STRUCTs in a GVL

2021-03-26T14:50:07.789000Z

Found the solution! I'll post it.

Thanks again.

Ryan

STRUCTs in a GVL

2021-03-26T14:42:29.297000Z

Thanks! Yep, that solved the first problem!
Now I got another one, if you could solve it it would be great.

In the DUT declaration I got some Arrays, and in the GVL I don't know how to initiate it, it gives me an error.

STRUCTs in a GVL

2021-03-26T14:04:35.173000Z

Line 4 of your GVL, where you have
~~~ CL501 : STRUCT_CL501_HMI ( ~~~
I think should read
~~~ CL501 : STRUCT_CL501_HMI := ( ~~~

STRUCTs in a GVL

2021-03-26T12:59:31.828000Z

Hi everyone and thanks in advance for the replies. I need to rewrite an entire program in Codesys that was written in another program (let's just say that I have to migrate some Data Blocks).

So I began to copy the program by the variables so I would have everything in place when I would later copy the code itself.
I wrote down the variables that were in Data Blocks as variables in GVLs, and there was one thing I had to change. In the other program you can nest structures in data block/other structures, and in Codesys you can't do it. So i created an auxiliary folder and declared the STRUCTs I was going to use in the GVLs.

Everything worked fine, the problem rose when I had to initialize some variables in the GVLs. In the GVL declaration I just wrote down the initial values of the STRUCT following the online helper format, compiled it and nothing went wrong.
Now if I call a variable in a FB/PRG POU that has been initializated in the GVL it gives me this error: "No Matching "FB_Init" method found for instantiation of STRUCT..."

I didn't found a useful solution for this problem and I don't really know what to do with the METHOD call. I hope that you can comprehend my explanation and if that's not the case let me know, I will be more than happy to try to explain it better.

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