functions in S7 Simatic

botr

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• Dec 12, 2006

• #1

I have to write functions which will read in DB suitable word .
The address of word be passed as number 0-100
0 - DBW0
1 - DBW2
2 - DBW 4
3 - DBW 6
4 - DBW 8
5 - DBW 10
I ask about help very
To possibly function in STL or SCL
I greet

 

L D[AR2P#0.0]

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• Dec 12, 2006

• #2

What about the DB number ?

 

PeterW

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• Dec 12, 2006

• #3

If you don't need to specify the DB, its already open, then you can indirectly address the dataword. The pointer must be in WORD format.

example

L DBW[W_Pointer]

where W_Pointer is a variable of WORD format.

If you need to specify the DB as well, there are a number of different ways, need to say what you want to do.

 

botr

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• Dec 12, 2006

• #4

number DB is constant
For example:
OPN DB20
L #variable
L 1
<>I
SPB aa1
L DBW2
T MW10
aa1:
L #variable
L 2
<>I
SPB aa2
L DBW4
T MW10
aa2:
.........
.....
.....

 

PLucas

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• Dec 12, 2006

• #5

botr

I am not sure if I understand you correctly, but there is a Siemens Function that will do what I think you are trying to do.

Take a look at FC86 TBL_FIND TABLE, this is located in 'Standard Library' -> 'TI-S7 Converting Blocks', this might do what you want

Paul

 

L D[AR2P#0.0]

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• Dec 12, 2006

• #6

Here is an FC that will perform the function requested:

Code:

FUNCTION FC 2 : VOID
TITLE =read dbwx where x=iIndex * 2
VERSION : 0.1

VAR_INPUT
  dbBlock : BLOCK_DB ; 
  iIndex : INT ; 
END_VAR
VAR_OUTPUT
  iResult : INT ; 
END_VAR
BEGIN
NETWORK
TITLE =fetch dbwx where x=iIndex * 2
	  OPN   #dbBlock; 
	  L	 #iIndex; 
	  SLD   4; 
	  LAR1  ; 
	  L	 DBW [AR1,P#0.0]; 
	  T	 #iResult; 
	  SET   ; 
	  SAVE  ; 
END_FUNCTION

 

PeterW

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• Dec 12, 2006

• #7

PLucas said:

botr

I am not sure if I understand you correctly, but there is a Siemens Function that will do what I think you are trying to do.

Take a look at FC86 TBL_FIND TABLE, this is located in 'Standard Library' -> 'TI-S7 Converting Blocks', this might do what you want

Paul

Click to expand...

I believe this FC is to search for a pattern.