Simatic S7 Question

arocon · Aug 21, 2011

Could anyone please explain me the following code ? How do it got DB number ? What is the use of the current_offset and RT_Int_ Offset? Why used in the code ITD, SLD 3, LAR1 ?? What is doing the code in between CNT and LOOP_CNT ?

// set BR = 1
SET
SAVE

// load constants
L "GlobalConstants".RT_Int_DB
T #DB_T

pen

L "GlobalConstants".RT_Int_Number
T #RT_Number

L "GlobalConstants".RT_Int_Size
T #RT_Size

L #Table_ID
T #Table_ID_Temp

// check for a valid DB number
L 0
L #DB_T

pen
==I
SPB DNE
T #DB_T

pen

// open block
AUF DB [#DB_T

pen]

L 0
T #Current_Offset

L #RT_Number

CNT: T #RT_Int_Counter
L #Current_Offset
ITD
SLD 3
LAR1
// offset for table id is 12
L DBW [AR1,P#12.0]
L #Table_ID_Temp
==I
SPB OFD
L #Current_Offset
L #RT_Size
+I
T #Current_Offset
L #RT_Int_Counter
LOOP CNT
DNE: L 0
T #RT_Int_Offset
BE
OFD: L #Current_Offset
T #RT_Int_Offset
BE

Thanks

L D[AR2P#0.0] · Aug 21, 2011

How do it got DB number ?

Back in the mists of time, the author of this program decided to create a global constants data block. In that data block he decided to store the number of the data block relevant for this code segement. Why he did this, we will probably never know. Maybe he was waiting for some potatoes to cook and they took longer than expected ?

Code:

[SIZE=3][FONT=Times New Roman]L     "GlobalConstants".RT_Int_DB[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]T     #DB_To_Open
[/FONT][/SIZE]

later on in this epic program, we find:

Code:

[FONT=Times New Roman][SIZE=3]// open block [/SIZE][/FONT]
[SIZE=3][FONT=Times New Roman]      AUF   DB [#DB_To_Open]
[/FONT][/SIZE]

Simatic S7 Question

arocon

Member

L D[AR2P#0.0]

Lifetime Supporting Member

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