User manual

IEC61131 User and Reference Manual
April 22, 2008
247
configured. The log file will be deleted and a new log file created when all records
are filled.
The way full files are handled limits the effectiveness of a single log file. The file system on
the internal drive of the SCADAPack 330, SCADAPack 350 and SCADASense 4203
supports multiple data log files.
 The number of log files that can be configured for a each instance of the DLGF
function is a maximum of 65535.
 Each log file contains a minimum of 600 records and is configurable for maximum
of 65535 individual records. Each record contains a maximum of 8 configurable data
fields.
The figure below shows the log file, record and field structure for data logging using multiple
log files.
Records are added to the buffered data in RAM each time the log data input for the DLGF
function transitions from OFF to ON.
After 1 minute Log file 1 is created and the records that have been added to the buffered
data in RAM are added to Log file 1 in the internal drive or the mass storage drive.
This process repeats until the configured number of records per file, Record N, for Log file 1
is reached.
Again records are added to the buffered data in RAM each time the log data input for the
DLGF function transitions from OFF to ON.
After 1 minute Log file 2 is created and the records that have been added to the buffered
data in RAM are added to Log file 2 in the internal drive or the mass storage drive. Log file 2
is saved in the internal drive or the mass storage drive.
This process repeats until the configured number of records per file, Record N, for Log file 2
is reached and continues to repeat until the configured number of records, Record N, for Log
file N is reached.
Now the entire data log is filled. After another 600 records the buffer will be full and no
further buffering will occur. The log status register will have the number 17 indicating the
status failed to write data.
Log file N
Record 1
Field 1
Field 2
Field 8
Record 2
Field 1
Field 2
Field 8
Record N
Field 1
Field 2
Field 8
Log file 2
Record 1
Field 1
Field 2
Field 8
Record 2
Field 1
Field 2
Field 8
Record N
Field 1
Field 2
Field 8
Log file 1
Record 1
Field 1
Field 2
Field 8
Record 2
Field 1
Field 2
Field 8
Record N
Field 1
Field 2
Field 8