HansAndersen
Member
Code:
1234 --> Db1.dbd0=1234
5678 --> Db1.dbd0=5678
Db1.dbd4=1234
9abc --> Db1.dbd0=9abc
Db1.dbd4=5678
Db1.dbd8=1234How To SOLVE This Proplem In S7-300 With Stl.
Thanks
Last edited:
Reverse Fifo Table_s7-300
- Thread starter HansAndersen
- Start date
How To SOLVE This Proplem In S7-300 With Stl.
Thanks
HansAndersen
Member
OP
Madman said:
tHANK YOU SO MUSH.BUT I DIDNT MENTION IT WILL CONTINIUE TO DBD160
L D[AR2P#0.0]
Lifetime Supporting Member
Here's an FC that will do the job. I have tested this in the simulator using a FIFO containing 10 double words.
Code:
FUNCTION FC 5 : VOID
TITLE =
VERSION : 0.1
VAR_INPUT
dwDataToAdd : DWORD ;
iFifoSize : INT ;
dbToUse : BLOCK_DB ;
END_VAR
VAR_TEMP
iLoopCount : INT ;
dwPointerDec : DWORD ;
END_VAR
BEGIN
NETWORK
TITLE =
L P#4.0;
NEGD ;
T #dwPointerDec;
L #iFifoSize;
+ -2;
L P#4.0;
*D ;
LAR1 ;
OPN #dbToUse;
L #iFifoSize;
+ -2;
SHUF: T #iLoopCount;
L DBD [AR1,P#0.0];
T DBD [AR1,P#4.0];
L #dwPointerDec;
+AR1 ;
L #iLoopCount;
LOOP SHUF;
L DBD [AR1,P#0.0];
T DBD [AR1,P#4.0];
L #dwDataToAdd;
T DBD [AR1,P#0.0];
SET ;
SAVE ;
END_FUNCTIONalternative:
L #number
L DB1.DBD 0
==R
JC qqqq
CALL "BLKMOV"
SRCBLK :=P#DB1.DBX0.0 BYTE 164
RET_VAL:=MW100
DSTBLK :=P#DB1.DBX170.0 BYTE 164
L #number
T DB1.DBD 0
CALL "BLKMOV"
SRCBLK :=P#DB1.DBX170.0 BYTE 160
RET_VAL:=MW100
DSTBLK :=P#DB1.DBX4.0 BYTE 160
qqqq: NOP 0
you db1
L #number
L DB1.DBD 0
==R
JC qqqq
CALL "BLKMOV"
SRCBLK :=P#DB1.DBX0.0 BYTE 164
RET_VAL:=MW100
DSTBLK :=P#DB1.DBX170.0 BYTE 164
L #number
T DB1.DBD 0
CALL "BLKMOV"
SRCBLK :=P#DB1.DBX170.0 BYTE 160
RET_VAL:=MW100
DSTBLK :=P#DB1.DBX4.0 BYTE 160
qqqq: NOP 0
you db1
Madman said:
I was under the impression that this won't work. The first 4 bytes would be copied over and over and over.
From the help file:
-Data is copied in the direciton of ascending adresses (dbb0 to dbb4, then dbb1 to dbb5, and when it gets to dbb4 it copies the data to dbb8, however dbb4 contains the data from dbb0......)
-The source and destination area must not overlap. See previous point
So best to use a DB just for the temporary holding of the data or use a DB twice the size as in Madman's first suggestion.
We use a second DB for the temporary holding of the data.
Thats what it says in my Help-file
I was taught to never use overlapping area's when I first learned S7. Tested and tried it. It didn't work 'back then'.
But hey, if they 'fixed' it, all the better. Will test and try it again when time permits.....
HansAndersen
Member
OP
I had used SFC20 before asking question.It had worked properly.I didnt see any overlaping.The mean of overlap may be different thing here.So I wanted to try it in STL.I had used loop and also indirect adressing.It had become with a little different.Thanks to L D[AR2,P#0.0], I found correct way. STL code worked wery well.But I had to add (fp)not to write the values to all fifo immediately.
S7Guy
Member
Keep in mind that there is a point when SFC20 will be more efficient. For smaller blobs of data, a loop is faster, but for very large bobs, SFC20 will be faster (it uses a fixed overhead plus a per-byte multiplier). You can look at the execution times of the various instructions and SFCs (or test it) to see what is the best for you.
Also, as others mentioned, you can't overlap the data with SFC20.
Also, as others mentioned, you can't overlap the data with SFC20.
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