Siemens SIMATIC S7-1200

Extended instructions
9.9 Recipes and Data logs
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
529
9.9.2.5
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.
Example Data log program
Example data log names, header text, and the MyData structure are created in a data block.
The three MyData variables temporarily store new sample values. The process sample
values at these DB locations are transferred to a data log file by executing the DataLogWrite
instruction.