Logging Software - BZ 7224

With the optional Logging Software enabled, Type 2250 becomes a versatile instrument for obtaining time histories. The Logging Software allows you to select freely among the broadband parameters and log them at intervals from 1 s to 24 h. At the same time L_Aeq and/or L_AF can be logged at 100ms intervals.

If Frequency Analysis Software BZ 7223 is enabled, the Logging Software additionally lets you log spectra at the same 1 s to 24 h periods.

Logging Software BZ 7224 incorporates a number of features designed to make difficult field work as manageable as possible.

Among the most salient of these features are the following:

Five user-definable markers can be set on-the-fly in the profile. Use these, for example, to clearly indicate specific noise sources
Markers can be set directly on the profile display using the stylus and the touch screen. Simply .tap and drag. on the part of the profile you want to mark and select a marker from the drop-down list
Markers can even be set 'after the fact'. The display covers the latest 100 samples (that is, 100 s of profile when logging at 1 s intervals, otherwise more) meaning that in most cases you can wait for the event (or disturbance) to stop before placing your marker. Alternatively, scroll back in the profile and set your marker
The profile display can be 'frozen' at any time (this happens automatically when you tap the screen), allowing you to work at ease
Voice annotations, using the commentary microphone, are attached to the exact point on the profile where the annotation is made. With the microphone on an extension cable, comments can be associated with particular parts of the profile without interfering with the measurement

All markers and annotations are saved with the measurement, see Fig. 8 and Fig. 9. No further bookkeeping is required. When exporting data to, for example, 7820 Evaluator software for further analyses, markers, as well annotations, are directly accessible on the profile.

Data are stored directly on SD or CF cards. BZ 7224 includes a suitable SD card. Data can be directly read from the SD card by the included PC software BZ 5503 (see page 11). Thiis means that even large amounts of data can be quickly transferred to a PC.

In order to give an indication of the amount of memory required, some examples have been listed in the following section. Values should be compared to the standard size of the SD cards used, which start at 128Mbyte.

For convenience, values for 1 s logging periods during 24 h are given. Other values easily compute from these:

Five broadband parameters, no statistics: 1Mbyte
All broadband parameters, one 100ms parameter: 3Mbyte
All broadband parameters, no statistics: 4Mbyte
All broadband parameters, one 100ms parameter, all 1/3-octave spectra: 30Mbyte
All broadband parameters with full statistics: 51Mbyte
All broadband parameters, one 100ms parameter, all 1/3-octave spectra, full statistics: 80Mbyte

Space needed for annotations and recordings must, of course be added to this. As a guideline, 10 s of voice annotation requires approx. 312 kB.

If Sound Recording Option BZ 7226 (see following section) is also enabled, Logging Software BZ 7224 becomes even more versatile. In this case the actual signal can be recorded during, for example, a noise event. Recordings can be controlled manually, or automatically by a level trigger. BZ 7226 includes a pre-recording of sound (size of buffer dependent upon sample rate, see specifications), which means that sound recorded prior to the identification of an event is also included in the recording. The combination of recording the actual signal and making voice annotations on a separate channel provides exceptional documentation capabilities.