Hi.

Think of building your coding around MOVE_BLK_VARIANT instruction.
Have a look at the description in the built-in software help.

Step 1:
The value you wish to add to the buffer ( #value )..
move that to an array of one element of the same type ( #ValueArray[0] ).

Step 2:
Pass on the one element array ( simply as #ValueArray )
It is good enough to pass the value (#value) directly
to variant type input in-out parameter of the FB.
Also pass on the buffer array (#bufferArray ... defined with multiple elements).


The Variant type is a pointer... "by reference" access.
So in actual fact the variable you link to is read/write.
(Yes and no... writing still needs in-out parameter!)

Step 3:
MOVE_BLK_VARIANT instruction +
code includes counters to ensure one element is filled.

See if this design idea works for you.
Also look at...
https://support.industry.siemens.com/tf/ww/de/posts/s7-1500-pointer-variant-any-auf-array-an-fc-bergeben/140246/?page=0&pageSize=10

w

enof

Hi! That seems promising. I'll give it a try.

TypeOf & TypeofElements instructions are not documented in the system manual. They are selectable in TIA and mentioned in "Comparison list for S7-300, S7-400, S7-1200, S7- 1500 Reference manual"
Guess I have to look @ 1500 manual (only which? is there an instruction list).

aha: the online tia help does describe them, pity it's not in pdf...

Thanks, it's appreciated

And as often when looking for a solution I already found that for this case I don't need a buffer anyway;)

(smile)
I used the S7-1200 as base and designing something.
..even if it is for academical purpose now

There were some errors in my earlier steps.
My earlier notes I will (strike-through) edit some of the incorrect assumptions.

The code attached as PDF is tested quickly in the simulator to be working.

FIGURE 1 - Triggering the function block call in OB1.

FIGURE 2 - Extracting the size of the buffer.. used by #index.

FIGURE 3 - The core of the solution: variant block move

Greetings.
w

enof

uh, wow!

re-established trust in 1200 instr. set and the s7 community!

Can I bother you with some house cleaning activities also? ;)

thanks

(smile)
..are you talking of "cleaning" programming coding
or are you actually literally talking of cleaning house.

(bigger smile, joking)
I am not sure you can afford my rates (price),,,, (wink)

[serious]
What is done for the S7-1200 will work for the S7-1500 too..
if ever there were doubt in anyone's mind.