101BExtended instructions
8.7 Data logging
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
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Viewing data logs from a Web browser
Even if you do not use the Web server feature, you can view data logs directly from a Web
browser such as Internet Explorer or Mozilla Firefox. Simply enter the following text into the
address bar of your browser using the IP address of your CPU and the actual name of the
data log file you provided in STEP 7 instead of "MyDataLog":
http://192.168.0.1/DataLog.html?FileName=MyDataLog.csv
The fixed addresses of data log files also make it possible to access them through third party
file collection tools.
8.7.4
Limits to the size of data log files
Data log files share PLC load memory space with the program, program data, configuration
data, user-defined web pages, and PLC system data. A large program using internal load
memory requires a large amount of load memory and there may be insufficient free space for
data log files. In this case, you can use a "Program card" to increase the size of load
memory. S7-1200 CPUs can use either internal or external load memory, but not both at
once.
Refer to the memory card chapter for details about how to create a "Program" card
(Page 104).
Maximum size rule for one Data log file
The maximum size of one Data log file may not exceed 25% of the load memory size
(internal or external). If your application requires more Data log entries, then use the
"DataLogNewFile" instruction to create a new file when all records in the first file are filled.
See the table below for the maximum sizes of one Data log file.
Table 8- 137 Load memory size and maximum size for one Data log file
Data area
CPU 1211
CPU 1212
CPU 1214
Data storage
Internal load memory
flash memory
1 MB
(250 KB max. for
one Data log file)
1 MB
(250 KB max. for
one Data log file)
2 MB
(500 KB max. for
one Data log file)
External load memory
Optional "Program card"
flash memory cards
2 MB or 24 MB depending on the SD card size
(500 KB max. for one Data log file using a 2 MB card)
(6 MB max. for one Data log file using a 24 MB card)
User program and program
data, configuration data, Data
logs, user-defined web
pages, and PLC system data