Atec Bruel-Kjaer-2250-2270 - Manual (Page 10)

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A periodic report is similar to the Measurement Total of the Logging software, except it is made periodically.
It is useful for analysing sound levels over extended periods. If you combine periodic reports with level-
triggered event markers and Signal Recording Option BZ-7226, you have an overview as well as a focus on
essential details.
A typical setup for 24 hr of extended logging might be:
• Continuous measurement
• Hourly periodic reports
• Level triggered marker for events above L
AF
= 60 dB(A)
• Signal Recording of events (please refer to the Signal Recording Option BZ-7226)
• Logging of other parameters as required (please refer to the Logging Software BZ-7224)
After the measurement, you can check L
dn
or L
den
, the Total and the periodic reports, and then browse the
events and sound recordings to verify the quality of your measurements.
Signal Recording Option – BZ-7226
Signal Recording Option BZ-7226 works with all other applications. In all cases it allows you to make
recordings of the actual measured signal, that is, the microphone signal used for acoustic measurements or
the accelerometer used for vibration measurements (this must not be confused with recorded voice
annotations, which use the commentary microphone). Recordings are automatically attached to the
measurement and kept with it, even after transfer of the data to a PC.
One purpose of the Signal Recording Option is to let you record the measurement signal in order to identify
and document sound sources. Automatic gain control is available to allow for any signal level. For example:
• The measured L
Aeq
at 57 dB, did it actually stem from the rather distant compressor, or from other
sources such as nearby birds or traffic? Not necessarily easy to evaluate on site, very difficult to
document convincingly later. If the signal is recorded: No discussion
• Is it really true that this noise is impulsive and should be penalised accordingly? If the signal is recorded:
There may still be an argument, but it is then based on facts
• Exceedances were identified while no operator was present. Did they originate from the plant under
investigation or from another source. If the signal is recorded: No discussion
Another important use of signal recording is to record the signal for later processing, such as analysing an
engine run-up or a machinery process cycle.
With Sound Level Meter Software BZ-7222 and Frequency Analysis Software BZ-7223, Signal Recording
Option BZ-7226 lets you do the following:
• Record all or parts of the measured signal giving rise to specific results, levels and spectra
• Set up your instrument so that recording can be set to start automatically when the measurement is
started, or you can initiate recordings manually
With Logging Software BZ-7224 and Enhanced Logging Software BZ-7225, additional options are available:
• Signal recording can be associated with the Event Marker. Use the Event key or set an event marker on
the profile display: The sound during the event is recorded and attached to the appropriate part of
the profile
• Automatic detection of events based on level exceedance is also possible, meaning that recordings can
also be initiated when no operator is present
In all of the above cases the maximum duration of recordings can be set (the analyzer is only limited by
available storage on the memory card currently in use). Recording signals may require large amounts of
storage, therefore Signal Recording Option BZ-7226 allows you to decide on the trade-off between storage
needed and recording quality (sampling rate).
Overview of Software Features
The table below presents a summary of the features of each of the application modules available with
Type 2250 and Type 2270. See Specifications for details.