Siemens SIMATIC S7 System Manual page 294
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101BExtended instructions
8.7 Data logging
Parameter and type
ID
In/Out
HEADER
In/Out
DATA
In/Out
DONE
OUT
BUSY
OUT
ERROR
OUT
STATUS
OUT
A data log file is created with a pre-determined fixed sized based on the RECORDS and
DATA parameters. The data records are organized as a circular log file. New records are
appended to the data log file, until the maximum number of records that is specified by the
RECORDS parameter is stored. The next record written will overwrite the oldest record.
Another record write operation will overwrite the next oldest data record and so on.
Note
If you want to prevent overwriting any data records, then you can use the DataLogNewFile
instruction to create a new data log based on the current data log, after the current data log
has stored the maximum number of records. New data records are stored in the new data
log file. The old data log file and record data remains in flash memory of the CPU.
294
Data type
Description
DWord
Data log numeric identifier: You store this generated value for use with other
Data log instructions. The ID parameter is only used as an output with the
DataLogCreate instruction. (Default value: 0)
Symbolic name access for this parameter is not allowed.
Variant
Pointer to data log column header names for the top row of the data matrix
encoded in the CSV file. (Default value: null).
HEADER data must be located in DB or M memory.
The characters must follow standard CSV format rules with commas
separating each column name. The data type may be a string, byte array, or
character array. Character/byte arrays allow increased size, where strings
are limited to a maximum of 255 bytes.
The HEADER parameter is optional. If the HEADER is not parameterized,
then no header row is created in the Data log file.
Variant
Pointer to the record data structure, user defined type (UDT), or array.
Record data must be located in DB or M memory.
The DATA parameter specifies the individual data elements (columns) of a
data log record and their data type. Structure data types are limited to a
single nesting level. The number of data elements declared should
correspond to the number of columns specified in the header parameter.
The maximum number of data elements you can assign is 253 (with a
timestamp) or 255 (without a timestamp). This restriction keeps your record
inside the 256 column limit of a Microsoft Excel sheet.
Bool
The DONE bit is TRUE for one scan, after the last request was completed
with no error. (Default value: False)
Bool
0 - No operation in progress
1 - Operation on progress
Bool
The ERROR bit is TRUE for one scan, after the last request was terminated
with an error. The error code value at the STATUS parameter is valid only
during the single scan where ERROR = TRUE.
Word
Execution condition code (Default value: 0)
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
- Quick Links:
- Introducing the S7-1200 Plc
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