Go back to the SCL source, starting from the AWL compiled code

Hello to everyone.

I have an FB created from an SCL source, but that source is not available anymore.

I would like to rebuild the SCL code starting from the FB, but i have some question about how to interpret it.

For example, in the FB i found the following code:

SET
SAVE
=     L      0.1
U     DB500.DBX  205.1
=     #OUT
=     DBX  288.0

Reagrding this to lines, my questions are:

1) How it is possible replace a multi assignment like  U     DB500.DBX  205.1
                                                                             =     #OUT
                                                                             =     DBX  288.0

2) How is possible to assigne a variable like  =     DBX  288.0?
    I tryed to write in SCL like AUF DBxx, but does not exist, where is declared the DB's number?

Thanks a lot.

Regards.

Duccio.

Hi Duccio,

which Software do you have? Step7 or Step7TIA?

I think you have to use the symbolic names.

If DB 500 is "data_db" , DBX 205.1 is "status_bit" and DBX 288.0 is "bit0"

out := data_db.statusbit
bit0 := data_db.statusbit

Hi Miami,

Your solution, is the first things i did, but if you compile an SCL code like you wrote,the compiled code will not appear like :

U Variable1

= Variable2

= Variable3

Regiarding the DB instead, my question is to wich DB is related the variable DBX 288.0.

Why for the first one the Address is complete and for the second there is only the last part?

Whit AWL i would write :

AUF DBzzz

U DBX 0.0

= DBX0.1

in this case the DB is clear, but in the posted code it is not.

Regards.

Duccio.

Try this: 

out := data_db.statusbit;
bit0 := out;

I think you should not look so much on the compiled code, it may vary depending on several circumstances, e.g. SCL version.

In STL you can use  

A DB500.dbx 0.1

 or 

OPN DB500
A DBX 0.1

In the address register 1 (AR1) the actual DB is stored. Any DB access without defining the DB to use (e.g. A DBX 0.1) use the DB stored in AR1.
When you program "A DB500.DBX 0.1", the DB 500 is written into AR1 and then  "A DBX 0.1" isexecuted.

As long as you do not change the AR1 with the DB-open-command "OPN DB xx" or with a full qualified DB access like "L DB500.DW4" all part qualified DB accesses use the same DB.

This is the SCL code i wrote:

FUNCTION_BLOCK FB1000

VAR
    OUT:BOOL;
END_VAR

OUT:=DB500.DBX0.0;
DB500.DBX0.1:=OUT;
END_FUNCTION_BLOCK

and this is the compiled code in AWL

SET
SAVE
=     L      0.1
U     DB500.DBX    0.0
=     #OUT
U     #OUT
=     DBX  0.1
U     L      0.1
SAVE
BE

Yes, the First part of the DB is obmitted, but it is little bit different, the code im trying to generate is:

SET
SAVE
=     L      0.1
U     DB500.DBX    0.0
=     #OUT
=     DBX  0.1
U     L      0.1
SAVE
BE

Regards.

Duccio

The original SCL code was compiled with option CreateDebugInfo off, your code was compiled with option on.

You can set this option from the compiler settings menu (Extras), or you can add the option in the sourcefile which I'd always recommend for every SCL source file:

{
    SCL_CreateDebugInfo := 'n';
}

FUNCTION_BLOCK FB1000

...

Hi Thomas,

You are right, i've set to off the debug option, and the compiled code its the same.

thanks.

Regards

Duccio.