HT instruments HT157 - Manual (Page 19)

HT155 - HT157
EN - 17
5.1.3. 24-HOUR ANALYSIS OPERATIONS
The “24Hours” analysis is a statistic analysis, but has a fixed duration of 24 hours starting
from the programmable date/time, and divides the measuring results of the various
quantities in 24 intervals of one hour each. After the analysis has automatically stopped,
the calculated values of Ld, Ln and Ldn noise are also provided. This mode is appropriate
when it is necessary to repeat an analysis of a certain duration (measuring time) from the
same second of each hour during a whole day.
CAUTION
The measuring time within each interval can be set (see § 4.6.2) in a range of
1min
 59min. For a measuring time different from this range, the instrument
automatically considers a time of 20min
1. Use the keys “ ” or “ ” to select the “24Hours” icon (see Fig. 14) and confirm with
“ ”.
Fig. 14: Selection of 24Hours analysis
2. The instrument shows the following screen relevant to the measured quantities in
numerical form:
 Line 1
 Line 2
 Lines 3-8
 Line 9
Fig. 15: 24Hours analysis screen in numerical form
3. Consider the following table for the meaning of the items found in screen of Fig. 15: