Access to ARRAY elements in STL

Hello,

I want to access the elements of an array with the aid of a variable (indirect accessing the elements of an array).

For example, an array of type byte is defined (byte_array [1..10] of BYTE).
I want to access the element nr. 3 from the array using a variable (let's say x, where x is defined as BYTE type), so to make something like byte_array[x] (instead of byte_array[3]).
This byte_array is defined as a static variable inside a FB.

How can I achieve this?
Thanks!

Call this FC from your FB.


Here's the FB I used to test it:

Thank you!

I noticed your previous post Step 7 using a variable as an array index.
From this I understand (please correct me if I'm wrong) that when you access different data types you must use SLD with different increments:
binary - SLD 0
byte - SLD 3
word - SLD 4
dword - SLD 5

In the Siemens Step7 documentation for ANY data type (Appendix A.3.4.5) it says that ANY covers 10 bytes & that the address is stored in the format Byte.Bit where the byte address is stored:
- in bits 0 to 2 of byte 7
- in bits 0 to 7 of byte 8
- and in bits 3 to 7 of byte 9
and the bit address is stored in bits 0 to 2 of byte 9

So from this I understood that the scope of SLD 3 instruction is to calculate the new byte address = prepare the increment (the offset) that is to be added to the base =; without overwriting the bit address = the 3 bits (0 to 2) of byte 9.

Question: why is it necessary to make SLD 4 & SLD 5 (preserve bites 0 to 3 or 0 to 4)? When working with word & dword the bit address of the ANY data type covers 4 & 5 bites?

Many thanks!

Euhm don't really understand your question SLD3 is the same like multipling by 8

What LD is doing is converting the Integer adress to a DWORD adress

There is a post about it, will look it up for you