Hi.

I try to implement an array of struct in IEC61131-3 ST language.

The C code look like this:

Struct BDD
{
Unsigned char a1;
Unsigned int a2;
Unsigned int a3;
Unsigned int a4;
}
 
struct BDD BDD_table[4] = {
{'X', 1, 1, 2},
{'a', 0, 100, 0},
{'a', 1, 100, 2},
{'X', 2, 5, 4}
};

So:

How to declare array of struct and fill inn data in array in ST language?

Thanks!

Best Regards

Hans Pettersson

I believe you got a reply at PLCS.net.

Did that address your problem or do you need more help?

Originally created by: Roger Christopher

To declare a structure:

TYPE BDD :

STRUCT

a1 : BYTE;

a2 : INT;

a3 : INT;

a4 : INT

END_STRUCT

END_TYPE

To declare an instance of an array of structures:

VAR

BDD_Table : ARRAY[0..3] OF BDD;

END_VAR

To initialise the array in ST:

BDD_Table[0].a1 := 'X';

BDD_Table[0].a2 := 1;

BDD_Table[0].a3 := 1;

BDD_Table[0].a4 := 2;

BDD_Table[1].a1 := 'a';

BDD_Table[1].a2 := 0;

BDD_Table[1].a3 := 100

BDD_Table[1].a4 := 0;

BDD_Table[2].a1 := 'a';

BDD_Table[2].a2 := 1;

BDD_Table[2].a3 := 100

BDD_Table[2].a4 := 2;

BDD_Table[3].a1 := 'X';

BDD_Table[3].a2 := 2;

BDD_Table[3].a3 := 5;

BDD_Table[3].a4 := 4

There is a way of declaring initialisation values with the variable declaration, but I can never remember the syntax (bit fussy!)

Regards

Roger

Sorry but you mentioned initialize the array you can also do it directly in the declarations by using:

BDD_Table : ARRAY[0..3] OF BDD = (a1 := 'X',a2 :=1,a3 :=2, a4:=3),(a1:='Y',a2 := 2,a3:= 3,a4:= 4); etc...

Just another way.