PLC S7-1500 SQL-Connection - received data shifted by 1 byte --why?

Question

i´ve been successfully using a S7 1500 PLC in combination with an SQL-Server for quiete some time now. I set everything up like mentioned here: S7SQL-Guide-Stackoverflow Today i tried to add a second parameter to my SQL-Query. So I made something like this:

select Number1,Number2 from MYTABLE WHERE Apple = red and Sky = blue

The S7 sends the telegram, and the SQL-Server replies. So far so good.

I set up the size of TokenColumnMetaData accordingly to my wireshark record, compiled and send the updates to my PLC. Now the part which I don´t understand:

I am expecting to receive the value "12345" so again I used wireshark to see what I should expect:

So what I got is: 39 30 00 00, which is 12345 just the bytes are reversed -no problem so far, but when I check on S7-side, I see this:

My input is shifted by 1 Byte. How can I solve this? Unfortantely I don´t have deeper knowledge of the code provided by Siemens for this application.

Edit:

Screenshot of typeUseCaseSpecificTokenrow

Answer 1

Sometimes weird memory stuff happens when the data type comprises an odd number of bytes.

Siemens starts each element on an even memory address. So if Length is at address 0 and Data is at 2-5, then address 1 may be getting the first byte that is intended for Data

Address	Data	Element
00	04	Length 0
01	39
02	30	Data 0, byte 0
03	00	Data 0, byte 1
04	00	Data 0, byte 2
05	08	Data 0, byte 3
06	47	Length 1
07	94
08	03	Data 1, byte 0
09	00	Data 1, byte 1
10	00	Data 1, byte 2
11	00	Data 1, byte 3
12	00	Length 2
13	00
14	FD	Data 2, byte 0
15	10	Data 2, byte 1
16	00	Data 2, byte 2
17	C1	Data 2, byte 3