Siemens SIMATIC S7-1200 - Page 528

Extended instructions
9.9 Recipes and Data logs
S7-1200 Programmable controller
528 System Manual, V4.2, 09/2016, A5E02486680-AK
Size of individual data elements
Log data is stored as character bytes in the CSV (comma separated values) file format. The
following table shows the number of bytes that are required to store each data element.
Data type
Number of bytes (includes data plus one comma byte)
Bool
2
Byte
5
Word
7
DWord
12
Char
4
String
Example 1
: MyString String[10]
The maximum string size is assigned as 10 characters.
Text characters + automatic padding with bla
nk characters = 10 bytes
Opening and closing double quote + comma characters = 3 bytes
10 + 3 = 13 total bytes
Example 2
: Mystring2 String
If no size is assigned with square brackets, then 254 bytes is allocated by d
e-
fault.
Text characters + automatic padd
ing with blank characters = 254 bytes
Opening and closing double quote + comma characters = 3 bytes
254 + 3 = 257 total bytes
USInt
5
UInt
7
UDInt
12
SInt
5
Int
7
DInt
12
Real
16
LReal
25
Time
15
DTL
24
Number of records in a data log file
The RECORDS parameter of the DataLogCreate instruction sets the maximum number of
records in a data log file.
Time stamp bytes in one data record
● No time stamp = 0 bytes
● Time stamp = 20 bytes