Hi all,

I need to write a function where an operator will be able to press a button on the OP and so part of DB will be reset (all Value set to false – or to its default values).

The difficulty lies in in the need of one function which I could implement in few different projects. In those Projects the DB as well as the length may differ….

Please see attached screenshot.

Within FB1 I need to program sth like:

If Reset THEN

…….. (Reset  Dest_DB)

End_if;

As you can see the DB number, start bit and the length are not the same.

Any hints?

Greetings.

Hi, 

Have a look at this link:

In STEP 7 (TIA Portal), how do you initialize structures in optimized memory areas in the S7-1500?

The answer will very much depend on what PLC (and version) you have.

Making all the bits zero is one thing.. but making those go to a specific value is less easy. I suggest you have x2 parameters. One for source and one for destination. The source will have the values as you want them to be on reset and the destination is the DB that is used actively by the program.

You can use a block move or variant block move from one structure to the other. The command will differ from the PLC used.

Are these hints good enough? need more from someone?
w

PS: consider using non-optimised structures and UDT (user defined type) to construct the two DB entries.

Hi,

Pleas have a look at the attachment.

Following the MicroMan's link I've tried the first option:

But I have got the following Warning

When the input parameter '#IN_bInitialize' is written, you do not access the operand that was transferred as actual parameter, but rather only the formal parameter of the block.

So after that I found Warning on reset FB input parameter

so I've changed Dest_DB_2 to an InOut but then I'm getting Invalid Assignment error

So the last but not least I've tried the William_B's suggestion but then I am getting the same error messages as with the first option 

BTW I’ve just checked and my DB are non-optimized (I guess it is so by default)

AutoGen_756614

Hi,

 

Pleas have a look at the attachment.

 

Following the MicroMan's link I've tried the first option:

But I have got the following Warning

When the input parameter '#IN_bInitialize' is written, you do not access the operand that was transferred as actual parameter, but rather only the formal parameter of the block.

 

So after that I found Warning on reset FB input parameter

so I've changed Dest_DB_2 to an InOut but then I'm getting Invalid Assignment error

 

So the last but not least I've tried the William_B's suggestion but then I am getting the same error messages as with the first option 

BTW I’ve just checked and my DB are non-optimized (I guess it is so by default)

Using the ANY type is not quite fitting in to what fits the advise given.

Maybe try something else...
Look at the following

POKE_BLK(AREA_SRC:= <Operand>,

         DBNUMBER_SRC:= <Operand>,

         BYTEOFFSET_SRC:= <Operand>,

         AREA_DEST:= <Operand>,

         DBNUMBER_DEST:= <Operand>,

         BYTEOFFSET_DEST:= <Operand>,

         COUNT := <Operand>)

In essence it will be able to copy one block into another block.. just like you want to do with your code. So the pointer will be stretched over the various parameters of the instruction.. but it will do what you want from it.

.... I assume you are aiming to use an S7-1x00 PLC.

w 

Sorry for not mentioning but I have 315F and TIA V13 sp4

Wow strange, have somebody deleted MicroMan's Post???

Following his last post (which I cannot see now – or I just confused the threads) I learned about READ_DBL

I’ve also seen William_B your discussion with salrandazzo regarding it.

Anyway I’ve figured out that for my reason I can use both…. BLKMOV as well as READ_DBL…

So can I simply use one of them or should I use specific one?

Greetings,

AutoGen_756614

Wow strange, have somebody deleted MicroMan's Post???

 

Following his last post (which I cannot see now – or I just confused the threads) I learned about READ_DBL

I’ve also seen William_B your discussion with salrandazzo regarding it.

Anyway I’ve figured out that for my reason I can use both…. BLKMOV as well as READ_DBL…

So can I simply use one of them or should I use specific one?

Greetings,

Designer's choice really.
Where will the DB with the default values be stored?
It is is on an external memory card.. then use READ_DBL;
else use the old fashion BLKMOV (not the same as BLK_MOV for S7-1x00!).

Personally I would go for BLKMOV.

Yes.. I also saw my good friend Microman's post too.
If you ask nicely the Moderators are willing to delete a user's post.
BUT it can easily be the Siemens' servers - we have been experiencing troubles throughout the day.

At least you got some new knowledge through Microman
- please be so kind as to thank him for his positive efforts.

Happy coding.   (naughty smile)
w

AutoGen_756614

Wow strange, have somebody deleted MicroMan's Post???

 

Following his last post (which I cannot see now – or I just confused the threads) I learned about READ_DBL

I’ve also seen William_B your discussion with salrandazzo regarding it.

Anyway I’ve figured out that for my reason I can use both…. BLKMOV as well as READ_DBL…

So can I simply use one of them or should I use specific one?

Greetings,

 Hi,

I just removed my post as I found it only applicable for standard applications. I was not sure about the requirements in this case so I decided to remove it before I confuse someone.  Anyways for information only the link from my deleted post:

Initialisation of DB by using the SFC83

Sorry if I confused anyone with my removed post.