Log Buffer Configuration - Siemens 9810 Series User Manual

Log buffer configuration

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A. Circular (FIFO) logging mode: when the log is full, a new record overwrites the oldest record
B. Stop-when-full logging mode: when the log is full, any new records are not logged
The log buffer depth is the maximum number of records that can be stored in the
meter's short-term memory (RAM) for a particular log.
After records are captured in the log buffer in the meter's short-term memory, they
are replicated to the long-term memory. Because of inherent differences between
short-term (volatile) and long-term (non-volatile) memory, records can be added
more quickly to the short-term memory than they can be copied to long-term
memory.
The logs in the default logging framework have their log buffer depths pre-
configured to a value suitable for most applications. But you can configure the log
buffer depth for your applications, if required (for example, to help ensure the
continuity of critical data in high-speed logging scenarios or to optimize usage of
your meter's memory for your particular logging configuration).
If you are logging data at high speeds, it is important to review your logging needs,
and find the right balance between data retention and memory optimization for
your particular situation.
NOTE: If you get a message that you do not have sufficient memory when you
try to create a new log or change the configuration of an existing log, you may
need to reduce the log buffer depths of other logs in order to make memory
available for the new log.
Fully buffered logs
A fully buffered log (e.g., a Data Recorder or Waveform Recorder module) is one
where the value of the Buffer Depth setup register is the same as the Depth setup
register. This means the buffer (short-term memory) is set up to use all the
available long-term memory allocated for that log. This ensures the buffer does
not run out of space before all the records are replicated to the long-term memory,
regardless of the recording speed (i.e., the rate of record captures).
You may want to use this configuration if you are logging critical data (for example,
revenue logs) or logging data at frequent intervals (for example, intervals less than
60 seconds). However, it is important to note that this configuration uses the most
short-term memory, or RAM (the meter has a maximum 10 MB of RAM available
for the log buffer depth).
Partially buffered logs
A partially buffered log (e.g., for a Data Recorder or Waveform Recorder module)
is one where the value of the Buffer Depth setup register is less than the Depth
setup register. This means the buffer (short-term memory) is set up to use only a
portion of the available long-term memory allocated for that log. This configuration
allows for a much larger log size (i.e., number of records). However this does not
ensure that the buffer does not run out before all the records are replicated to the
long-term memory (e.g., in the case of high-speed recording).
Logging
7EN05-0390-00