Strings WinCC -> S7-400 - PLCS.net

Jeebs · June 3rd, 2010, 07:41 AM

Hi,

Got a question thats been bugging my collegue.
We use WinCC to fetch data from a SQL DB. These are mostly strings.
Now we need to send a couple of these strings from WinCC to the PLC. We're using 8-bit type character strings.

The irritating part is that the string in the PLC has an additional character in front of the string. And we have no clue what this character represents.

Any of you know what gets added?

Thanks

Jeebs

TurpoUrpo · June 3rd, 2010, 09:24 AM

What do you mean by extra character? Is there more than lenght + array of chars + end mark of zero in it?

To clarify, this is what is normal string

Code:

Byte 0 := 2 (lenght of string)
Byte 1 := 'a' (first char)
Byte 2 := 'b' (second char)
Byte 3 := 0 (end mark)

Is there more than that?

LestatZA · June 4th, 2010, 10:43 AM

I normally do not use the string function for that kind of application, due to the length that is added to the front
I use a Char. array in my db.
This is the link directly as char string in wincc.
Hope that helps.
If you need a sample please PM me then I will make a sample project for you with a SQL call script.

June 3rd, 2010, 07:41 AM	#1
Jeebs Member Join Date: Feb 2007 Location: Leuven Posts: 1,059	Strings WinCC -> S7-400 Hi, Got a question thats been bugging my collegue. We use WinCC to fetch data from a SQL DB. These are mostly strings. Now we need to send a couple of these strings from WinCC to the PLC. We're using 8-bit type character strings. The irritating part is that the string in the PLC has an additional character in front of the string. And we have no clue what this character represents. Any of you know what gets added? Thanks Jeebs

June 3rd, 2010, 09:24 AM	#2
TurpoUrpo Lifetime Supporting Member Join Date: May 2008 Location: Switzerland Posts: 1,570	What do you mean by extra character? Is there more than lenght + array of chars + end mark of zero in it? To clarify, this is what is normal string Code: Byte 0 := 2 (lenght of string) Byte 1 := 'a' (first char) Byte 2 := 'b' (second char) Byte 3 := 0 (end mark) Is there more than that? Last edited by TurpoUrpo; June 3rd, 2010 at 09:26 AM.

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June 4th, 2010, 10:43 AM	#3
LestatZA Member Join Date: Jan 2010 Location: Bayern Posts: 48	I normally do not use the string function for that kind of application, due to the length that is added to the front I use a Char. array in my db. This is the link directly as char string in wincc. Hope that helps. If you need a sample please PM me then I will make a sample project for you with a SQL call script.

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