Wolters

Hello everybody;

I am a new user of Siemens S7

In a VAT i try to "modify variable"

View in hex

W#16#1234 into mw 260

W#16#5678 into mw 261

In md 260 i expected 12345678 in monitor mode

But this doesn't happen

It gives DW#16#12567834

What do i miss?

Wolters

I am confused

In the system i used before

2 bytes in a word 16 bit

12 => 1byte

34 => 1byte

1234 makes 2 bytes makes 1 word

So to me it lookes like mw is not used as a word but as a byte

Dear Wolters,

don't get confused yet you are just starting

Thenumber specifies the 1st. byte address, that's how you can see it.

And B (1 x byte), W(2x bytes).. specifies the total number of bytes.

Back to your example:

MD 260 is basically MB 260 + MB 261 + MB 262 + MB 263

So you need to write into MW 260 + MW 262 to get your result correct.

Best Regards.

Maybe the best way to understand is as follows:

Al memory is organized into bytes: MB 0, MB 1, MB 2, MB3, MB4 ....

Word (MW) consists of two bytes.

Double Word (MD) conisist of two Word (MW) which is four bytes (MB)

When you are adressing for example MW0 as a result you get two bytes because it is a word with starting at B0

When you are adressing for example MW1 as a result you get two bytes because it is a word with starting at B1

.......

When you are adressing for example MW40 as a result you get two bytes because it is a word with starting at B40

same procedure is for double word:

When you are adressing for example DW40 as a result you get four bytes because it is a double word with starting at B40

I hope this someone helped

dragche

I hope this someone helped

For sure.