Hello, everyone! I run into problem while getting aquainted with TIA portal 20 (S-1200).

How do I convert Real variable to 2 Words (or 4 Bytes) and vise-versa 2 Words (4 Bytes) to Real?

And what is the problem when I try to get access to Real variable's bits? E.g. tag realVar1.%X0 sends me an syntax error, where realVar1 - tag of Real type. In the same time I can get access to bits of Word type tag e.g. wordVar1.%X0 is ok.

Thanks!

• REAL_TO_DWORD then slice access (%W0)
• REAL_TO_DWORD then LGF_SplitDWordToWords
• SERIALIZE or WRITE_LITTLE to an array of BYTE
• overlapping with an AT operator

AutoGen_9f800

How do I convert Real variable to 2 Words (or 4 Bytes) and vise-versa 2 Words (4 Bytes) to Real?

Slice access is allowed only for bit strings: BYTE, WORD and so on.

AutoGen_9f800

And what is the problem when I try to get access to Real variable's bits? E.g. tag realVar1.%X0 sends me an syntax error, where realVar1 - tag of Real type. In the same time I can get access to bits of Word type tag e.g. wordVar1.%X0 is ok.

The one that Jacek missed [wink]..

Move the REAL number into a memory address, like %MD20. Then you will be able to inspect the individual bits %M20.0 to %M23.7. Keep in mind that %M23.0 is the least significant bit and %M20.7 is the most significant bit.

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The At-overlay method is my all time favourite -- though you have to use it in code block parameter. It is possible to overlay several types and structures with each other. But to use it takes effort. Worth it to read the PLC system manual, find some forum posting or find an FAQ to help explain the how-to. (Thanks Jacek for providing a link for that!).