Dear All;

I have a SCL file in our backup. It directs inputs and outputs to DBs but i could not understand exactly what it does. Can someone please help me.

By the way which language is needed to understand scl.

SCl code is below;

Hello.

You require an add-on package to use SCL in Step7 V5.x. Step7 for TIA Portal has this functionality built-in.

See the attached text file for added commentary. Perhaps it helps.

~

alikol

Dear All;

I have a SCL file in our backup. It directs inputs and outputs to DBs but i could not understand exactly what it does. Can someone please help me.

By the way which language is needed to understand scl.

SCl code is below;

// Rev 1.0

// In handle digital , if the contact is NC deny it for it to become NO

VAR

N_BYTE, N_BIT : INT;

INPUT : INT;

OUTPUT : INT;

END_VAR

BEGIN

INPUT := WORD_TO_INT(DB1.DW0);

OUTPUT := WORD_TO_INT(DB1.DW2);

// Aggiorna Ingressi

FOR N_BYTE:= 0 TO (INPUT-1) DO

FOR N_BIT :=0 TO 7 DO

// Rev. 1.0

IF (DB2.DX[N_BYTE+30,N_BIT]) THEN

DB2.DX[N_BYTE,N_BIT] := NOT (I[N_BYTE,N_BIT]);

ELSE

DB2.DX[N_BYTE,N_BIT] := (I[N_BYTE,N_BIT]);

END_IF;

// Rev. 1.0

END_FOR;

END_FOR;

// Update Output

FOR N_BYTE:= 0 TO (OUTPUT-1) DO

FOR N_BIT := 0 TO 7 DO

Q[N_BYTE,N_BIT] := DB3.DX[N_BYTE,N_BIT];

END_FOR;

END_FOR;

END_FUNCTION

 

This code uses bits of DB2 bytes starting from byte 30 as masks indicating which inputs have NC contacts connected (1) and which ones have NO (0). Then it copies inputs to DB2 starting from byte 0. Those with NO contacts are copied as they are. Those with NC contacts are negated.

Finally, it copies bytes from DB3 starting from byte 0 to outputs without change.

To understand SCL you need to understand SCL. However, declaration and some program control statements are similar to Pascal.

IMHO, the presented code is very inefficient as it iterates bit by bit.

jacek d

 

alikol

Dear All;

I have a SCL file in our backup. It directs inputs and outputs to DBs but i could not understand exactly what it does. Can someone please help me.

By the way which language is needed to understand scl.

SCl code is below;

// Rev 1.0

// In handle digital , if the contact is NC deny it for it to become NO

VAR

N_BYTE, N_BIT : INT;

INPUT : INT;

OUTPUT : INT;

END_VAR

BEGIN

INPUT := WORD_TO_INT(DB1.DW0);

OUTPUT := WORD_TO_INT(DB1.DW2);

// Aggiorna Ingressi

FOR N_BYTE:= 0 TO (INPUT-1) DO

FOR N_BIT :=0 TO 7 DO

// Rev. 1.0

IF (DB2.DX[N_BYTE+30,N_BIT]) THEN

DB2.DX[N_BYTE,N_BIT] := NOT (I[N_BYTE,N_BIT]);

ELSE

DB2.DX[N_BYTE,N_BIT] := (I[N_BYTE,N_BIT]);

END_IF;

// Rev. 1.0

END_FOR;

END_FOR;

// Update Output

FOR N_BYTE:= 0 TO (OUTPUT-1) DO

FOR N_BIT := 0 TO 7 DO

Q[N_BYTE,N_BIT] := DB3.DX[N_BYTE,N_BIT];

END_FOR;

END_FOR;

END_FUNCTION

 

This code uses bits of DB2 bytes starting from byte 30 as masks indicating which inputs have NC contacts connected (1) and which ones have NO (0). Then it copies inputs to DB2 starting from byte 0. Those with NO contacts are copied as they are. Those with NC contacts are negated.

Finally, it copies bytes from DB3 starting from byte 0 to outputs without change.

To understand SCL you need to understand SCL. However, declaration and some program control statements are similar to Pascal.

IMHO, the presented code is very inefficient as it iterates bit by bit.

 Thanks for replay in advance.

I could not understand the below code.

 Is it your next question?

alikol

 I could not understand the below code.

IF (DB2.DX[N_BYTE+30,N_BIT]) THEN

DB2.DX[N_BYTE,N_BIT] := NOT (I[N_BYTE,N_BIT]);

jacek d

 Is it your next question?

alikol

 I could not understand the below code.

IF (DB2.DX[N_BYTE+30,N_BIT]) THEN

DB2.DX[N_BYTE,N_BIT] := NOT (I[N_BYTE,N_BIT]);

 

 Dear Jacek;

As i said my knowladge is limited.

Normally there should be a condition to be able to use then?  What is the condition to pass to second line?

Is my question so stupid or basic? 

No hard feelings. I wasn't sure if this is a question or just a confirmation that now you understand.

This is the condition: 

(DB2.DX[N_BYTE+30,N_BIT])

It reads a value of a boolean variable (or a bit) which can be TRUE (or 1 or H or ... few other mnemonics come to my mind too) or FALSE (or 0 or L).

E.g. N_BYTE = 10, N_BIT = 2 then the code above is equal to: 

(DB2.DBX40.2)

BTW. In manuals and alike very often longer version of above is given where explicit equality is used: 

(DB2.DX[N_BYTE+30,N_BIT]) = TRUE

But it is all the same.