Log Buffer Configuration - Siemens 9810 Series User Manual

Logging

Log buffer configuration

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 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).
You may want to use this configuration for logs with intervals greater than 60 seconds or with less
critical data. Because the records are partially replicated, this configuration uses less of the
meter's short-term memory, or RAM, in a log that is otherwise configured the same. This allows
you to make more RAM available for other logs with a higher logging frequency or more critical
data.
However, depending on your configuration, there may be instances where the log buffer fills up
faster than it can replicate records to long-term memory. In this case, you may lose records and
see gaps in your data.
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9410 series - User manual
7EN05-0336-09