Array of struct, ST language

[hapetter]

Hi.

I try to implement an array of struct in IEC61131-3 ST language.
The C code look like this:


Code:

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?

Thanks!

Best Regards
Hans Pettersson

 

[FrancisL]

As far as I know 1131/3 does not define array handling
What PLC is this for?
Typically in a PLC you would need to create your own arrays using Data blocks.

 

[hapetter]

Its a Beckhoff PLC. It has array handeling. I found out how to do

Thanks!

 

[FrancisL]

This may interest you, it explains state based control and how to create a table that compresses an array of states into a data table efficiently

http://controldraw.blogspot.com/2009/05/programming-equipment-states.html

Francis

http://www.controldraw.co.uk

 

[hapetter]

Interesting that you mention this. It actually was for this purposes I had the initial question about the struct. It is part of such a state machine where states and transistions is compressed into a table. It is super efficient. The link you had describe a variant of the system I use.

I did success to implement the system on my PLC for the first time yesterday. I have used it on microcontroller and C language only before.

- Hans