Data Log Example Program - Siemens S7-1200 System Manual

Extended instructions
8.7 Recipes and Data logs
UDInt
SInt
Int
DInt
Real
LReal
Time
DTL
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
See also
Monitoring the cycle time and memory usage (Page 792)
SIMATIC memory cards (Page 978)
8.7.2.5

Data log example program

This Data log example program does not show all the program logic necessary to get sample
values from a dynamic process, but does show the key operations of the Data log
instructions. The structure and number of log files that you use depends on your process
control requirements.
Note
General usage of Data log files
• Data log files are automatically opened after the DataLogCreate and DataLogNew File
operations.
• Data log files are automatically closed after a PLC run to stop transition or a PLC power
cycle.
• A Data log file must be open before a DataLogWrite operation is possible.
• A maximum of eight data log files may be open at one time. More than eight data log files
may exist, but some of them must be closed so no more than eight are open.
396
12
5
7
12
16
25
15
24
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG