Siemens S7-1200 System Manual page 394
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Also See for S7-1200:
- Operating instructions manual (132 pages) ,
- Programming manualline (74 pages) ,
- Manual (46 pages)
Table of Contents
Extended instructions
8.7 Recipes and Data logs
Maximum size rule for Data log files
The maximum size of one Data log file may not exceed the free load memory size or 500
MB, whichever is smaller. If your program uses more than one Data log file, then the
combined size of all Data log files may not exceed the free load memory size.
Table 8- 173 Load memory size
Data area
Internal load memory
flash memory
External load memory
Optional "Program card"
flash memory
Determining load memory free space
The amount of load memory free space varies during normal operations as the operating
system uses and releases memory. Use the following steps to view the load memory
memory size.
1. Establish an online connection between STEP 7 and the target S7-1200 PLC.
2. Download the program that controls your data log operations.
3. Create any optional user-defined Web pages that you need. The standard Web pages
that access data logs are stored in PLC firmware and do not use load memory.
4. Use the Online and diagnostic tools to view total load memory size and free space
(Page 783).
Calculating the size of a data log file (all data records)
When the data log file is created the maximum memory size is allocated. In addition to the
size required for all the data records, you must include storage space for a data log header
(if used), time stamp header (if used), record index header, and the minimum block size for
memory allocation.
Use the following formula to determine the size of your data log files and ensure you do not
violate the maximum size rule.
Data log file size = header bytes + data bytes + 512 bytes
394
CPU 1211C
CPU 1212C
1 MB
1 MB
4 MB, 12 MB, 24 MB, 256 MB, 2 GB, or 32 GB depending on the SD
card size
CPU 1214C
CPU 1215C,
CPU 1217C
4 MB
4 MB
System Manual, 03/2014, A5E02486680-AG
Data storage
User program and
program data,
configuration data,
Data logs, user-
defined Web pages,
and PLC system
data
S7-1200 Programmable controller
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