STL String copy (as ANY parameter) error!

Hello,

I want to copy a string of max. length (ex. from DB2) into the instance DB of the FB (ex.DB10 of FB10).

The string is given to FB10 as an input parameter of type ANY.
In the STAT area of instance DB10 I defined a string of max. length (254 same as length of source string in DB2).

I used BLKMOV (SFC20) and specified data type as byte (B#16#2) when preparing the ANY pointers.
The copy works OK (in VAT I can see that the string was copied into DB10).
In FB10 when I try to get the length (with IEC function FC21 LEN) of the just copied string I get this error (in Diagnostic Buffer):

Event 3 of 100: Event ID 16# 2522
Area length error when reading
Own local data, byte access, Access address: 45
FC number: 21
Module address: 28

Click to expand...

What is the problem?

Thanks!

Since you're dealing with a String here, are you sure you've allowed enough space in your DB? A String is actually two Bytes longer than the defined String length - the first Byte in the String holds the maximum length a String can be, the second Byte holds the current length.

This wouldn't bother SFC 20, it just drops the last two Bytes, however, FC21 will look at the length data at the start of the String and complain loudly if it can't find the last two Bytes.

Post your code (cut down to show the problem) as a zip attachment. (Copy the blocks to a library and archive the library)

RMA said:

.... the second Byte holds the current length.......... FC21 will look at the length data at the start of the String and complain loudly if it can't find the last two Bytes.

Click to expand...

FC21 reports no errors - it simply returns the value in the second byte of the string. If you contruct an any pointer to the L area at run time and pass it to FC21... that will you give you the Own Local Data Area Length Error. The fix is to modify the created any pointer to point to the V area instead.

Guess I phrased that badly, by "loud complaint" I meant the area length error in the diagnostic buffer, whereas, as far as I know, SFC20 doesn't give such an error.

L D[AR2 said:

Post your code (cut down to show the problem) as a zip attachment. (Copy the blocks to a library and archive the library)

Click to expand...

Hello,

Here is the project saved in library & archived.
So when trying to get the length inside FB you'll get an error (see the attachment).

Thanks!

PS: The help for IEC FC21 LEN says:

You can assign only a symbolically defined variable for the input parameter.

Click to expand...

You cannot use STAT variables whilst AR2 has been modified - you must restore AR2 before the call to FC21, not after.
(You have used AR2 to point to the temp area - this is what is being passed to FC21 and is why you get the error)

Thank you L D[AR2,P#0.0].
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