Rockwell Automation 9301 Series RSView32 Users Guide - Manual (Page 221)

Configuring data logging
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7–21
become unavailable because of network failures, or because of lack of
disk space on the primary path or where the ODBC database is
located.
If the primary path or ODBC database becomes unavailable,
RSView32 begins to store the data in a buffer. The buffer can hold up
to 64 Kb of data. When the buffer fills, or when the maximum
amount of time to buffer data has elapsed, if the primary path or
ODBC database is still unavailable RSView32 switches to the
secondary or backup path.
RSView32 checks periodically to determine whether the primary .dbf
file path or ODBC database has become available again. If the primary
path or ODBC database has become available, RSView32 switches
back automatically.
RSView32 also checks the status of the primary path or ODBC
database if the secondary or backup path becomes unavailable, and
will switch back if possible. If both paths are unavailable, RSView32
buffers the data. If the buffer fills and both paths are still unavailable,
RSView32 empties the buffer (the data in the buffer is lost) and begins
storing new data in the buffer. RSView32 continues checking both
paths until one becomes available.
If the data log file is locked by another program, for example if it is
opened with Excel, data is buffered for the time specified for
Maximum Time To Buffer in the Advanced Configuration dialog, and
then a new set of files is created on the primary path. If the secondary
path is not configured, the data is buffered for 10 minutes (the default
value for maximum time). If the maximum time is set to 0, a new file is
started immediately.
If the model is logging to the secondary path and the file is locked, the
behavior is the same. That is, the data is buffered and then a new file
created when the specified time period has elapsed.
You can also switch back to the primary path or ODBC database
manually, using the DataLogSwitchBack command (see page 7-25) or
the DataLogMergeToPrimary command (see page 7-26).