How to Clear thoose Temp variable ?
- Thread starter google08
- Start date
TurpoUrpo
Lifetime Supporting Member
So you want to clear MW2-MW8. You want to use variable #example declared on temp area where you first move 0 to have it clear, correct?
Are you using S7-300, S7-400, S7-1200 or some other plc?
Are you using S7-300, S7-400, S7-1200 or some other plc?
Peter Nachtwey
Member
According the the IEC specification VARs should be cleared on entry to a function
You shouldn't need to clear temporary variables, they should be cleared for you if Siemens is following the specification at all.
Memory variables, MWs are different.
You shouldn't need to clear temporary variables, they should be cleared for you if Siemens is following the specification at all.
Memory variables, MWs are different.
Manglemender
Member
Temp variables in S7 may contain any value when a block is called. Temp memory is allocated at runtime and the memory allocate will contain whetever values were left there by the last block to use that particular piece of memory.
Never ever use a temp variable in your code unless you have first set it to a value!
As for the OPs question, what's wrong with:
There are, of course, many other ways to achive the same end result.
Why do you want to clear MW's anyway? Most people use a MW because they want the value to be retained.
Nick
Never ever use a temp variable in your code unless you have first set it to a value!
As for the OPs question, what's wrong with:
Code:
L 0
T MD 2
T MD 6There are, of course, many other ways to achive the same end result.
Why do you want to clear MW's anyway? Most people use a MW because they want the value to be retained.
Nick
L D[AR2P#0.0]
Lifetime Supporting Member
PLC programming is not for you then.
PeterW
Member
Temp's are L memory, which can be any state.
M memory is not TEMP, I would use the TEMP area for temporary memory, that is after all what they are there for.
Look in the standard libraries, there is a FILL block where you can fill an area with whatever values you want, including zero's.
M memory is not TEMP, I would use the TEMP area for temporary memory, that is after all what they are there for.
Look in the standard libraries, there is a FILL block where you can fill an area with whatever values you want, including zero's.
uptown47
Lifetime Supporting Member
Code:
A #myResetButton
JC =M001
JU =M002
M001: L 0
T MD 2
T MD 6
M002: NOP 0Is that what you are trying to achieve.... but more adventurous??
Not too sure how to make it more 'interesting' than that really....
uptown47
Lifetime Supporting Member
.... or even more exciting....
Code:
A #destroyCivilisation
JCN BOMB
L 0
T MD 2
T MD 6
BOMB: NOP 0TurpoUrpo
Lifetime Supporting Member
.... or even more exciting....
Code:A #destroyCivilisation JCN BOMB L 0 T MD 2 T MD 6 BOMB: NOP 0
So you blow the bomb if you don't want to destroy civilization?
uptown47
Lifetime Supporting Member
No... the BOMB has No Operation ;-)
That's hidden code for which regions he's gonna bomb.
Load 0 (ie complete destruction) to Region 2 and Region 6.
If I'm not mistaken, that means Europe, Middle East, RSA, Japan, Greenland and China.
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