Compiled by SCL compiler to STL in Siemens!

MOeZ · Oct 16, 2012

Hi All,

In FB and FC that are compiled it to STL language.

When i open it those FB and FC, i have noticed that every start and End of code is written below.

SET
SAVE
= L 0.1
//
CODES
ARE
HERE
//
A L 0.1
SAVE
BE

So, my question is that, is it the good practice to write my own FC/FB to follow the same above? and as my understanding is correct, this L 0.1 is temp area of FB/FC and only can use inside FC/FB. Why compiler is start used this L 0.1 instead of using L 0.0 without declare anything in FC/FB? i am confused and I need suggestion from GURUs of forum. Thanks!

L D[AR2P#0.0] · Oct 16, 2012

The code you are seeing is for the internal OK flag which is passed out as the block result. By default OK is true and can be set to false if required. Why the compiler writer used L0.1 is anyones guess.

Code:

FUNCTION FC2202: VOID
OK:=False;    
END_FUNCTION

Generates the following STL:

Code:

      SET   
      SAVE  
      =     L      0.1
      CLR   
      =     L      0.1
      SAVE  
      BE

bara_hence · Oct 16, 2012

In my opinion never good practice not using symbols when possible..

Declare in the temp area a variable named eno_out or something alike and use that instead..

Code:

SET
= #eno_out
//
CODES
ARE
HERE
//
A #eno_out
SAVE
BE

If you dont need to control the ENO output just do

Code:

//
CODES
ARE
HERE
//
SET
SAVE
BE

Or just ignore the SET SAVE..

MOeZ · Oct 17, 2012

Thanks LD and where can i see?

L D[AR2 said:
The code you are seeing is for the internal OK flag which is passed out as the block result. By default OK is true and can be set to false if required. Why the compiler writer used L0.1 is anyones guess.

Code:

FUNCTION FC2202: VOID OK:=False; END_FUNCTION

Generates the following STL:

Code:

SET SAVE = L 0.1 CLR = L 0.1 SAVE BE

Many Thanks for explanation with sample code LD

again and Bara.
If i would like to know more, where can i see those meaning like L 0.0, L 0.1 ( internal OK Flag ), L 0.3 ....etc if possible. I want to use it by knowing meaning of those. I am using local data like below and is it OK to use? thanks!

L Alarm_Active // IN area of FB as Dword
T Alarm_Active_T // TEMP area of FB declare as Dword too

A L 0.0
= .....
A L 0.1
= .....
A L 0.3
= ....

L D[AR2P#0.0] · Oct 18, 2012

Are you writing the STL or is this STL code produced by the compiler?

MOeZ · Oct 18, 2012

I am writing STL in S7 and ..

Hi LD,

I am Writing and Learning STL as well. To efficient my code (to be standard) , i am looking Compiled STL code and your sample code on forum for my reference. Sometimes i am confusing. Thanks!

L D[AR2P#0.0] · Oct 18, 2012

You can refer to local data by it's absolute address but imagine what will happen if a new temp variable is added in front of the area you are referring to......

The solution is to use indirect addressing and AR1 to point to the named local variable. If a new temp is added no other code change is required.

Code:

      L     #Alarm_Active
      T     #Alarm_Active_T
      LAR1  P##Alarm_Active_T
      A      [AR1,P#0.0]
      =     #b00
      A      [AR1,P#0.1]
      =     #b01
//..
//... etc
//..

JesperMP · Oct 18, 2012

L D[AR2 said:
You can refer to local data by it's absolute address but imagine what will happen if a new temp variable is added in front of the area you are referring to......

The solution is to use indirect addressing and AR1 to point to the named local variable. If a new temp is added no other code change is required.

Code:

L #Alarm_Active T #Alarm_Active_T LAR1 P##Alarm_Active_T A [AR1,P#0.0] = #b00 A [AR1,P#0.1] = #b01 //.. //... etc //..

Wouldnt it be much simpler to just define a symbolic name for the TEMP variable ? If a variable is added so that the variable in question gets pushed, the code will automatically update.

L D[AR2P#0.0] · Oct 18, 2012

Alarm_Active_T is the name of the temp variable.

JesperMP · Oct 18, 2012

L D[AR2 said:
Alarm_Active_T is the name of the temp variable.

But then what is the problem if another variable is added as you describe ?

Jeebs · Oct 18, 2012

L "Some Value"
T #Some Temp Value // LW 0

A L 0.0
= ....

To prevent issues when you make #Some Other Temp Value LW0.

L D[AR2P#0.0] · Oct 18, 2012

I was answering the second part of post#4 where accesses to L0.0 etc are being used.

JesperMP · Oct 18, 2012

Just define TEMP symbols, and then use these symbolic names in stead of the absolute L0.0, L0.1 etc.

/bara_hence suggested this already in post #3.

L D[AR2P#0.0] · Oct 18, 2012

.. and how do you assign Alarm_Active (which is a dword) to these named booleans?

JesperMP · Oct 18, 2012

OK, I see that you answer the additional question in post #4. I missed that. I love it when a thread starts with a new question midway through.
Your answer in post #7 is correct.

Compiled by SCL compiler to STL in Siemens!

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