HL 6000 PC Correlator Operating Instructions
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Doc No. R12244
Jan/2009
3.1.16 Measuring Sound Speed
Measuring the “sound speed” is essential to generate an exact correlation result, especially for
unknown pipe materials and pipe characteristics (e.g. old pipes).
To measure the sound speed of the pipe, an artificial leak must be created and the distance from
this leak to the transmitters must be known. A slightly opened hydrant, for example, is an artificial
leak. The leak can be both within or outside the transmitters. It is recommended, however, that the
leak is produced outside the transmitters.
1. Place both sensors at suitable measuring points and open the artificial leak.
2. Start a new correlation with the “Start correlation” button (8). Finish the correlation when
you have received a suitable result.
3. Now open the “Speed measurement” dialogue by clicking button (16). Enter the correspond-
ing data in the query window.
The result is the sound speed of the pipe. Now close the artificial leak and perform the correlation
again using the new data to determine the distance to the real leak.
3.1.17 Zoom In
With this function activated, the correlation curve can be enlarged in the chosen range by clicking
and dragging with the mouse in the correlation window. This is particularly useful when two
peaks are very close to one another.
3.1.18 Zoom to Pipe Length
The correlation window is automatically adjusted so that the length of the pipe fills the whole
width of the window. By pressing the button once again, the whole measurement length is
displayed again and the pipe is reduced in the middle of the measuring range.
3.1.19 Load Correlation
A saved measurement can be loaded. If sound data was saved this is also loaded at the same time.
3.1.20 Save Correlation
First you will be asked whether you would like to save the actual sounds as well. If you choose
“no”, only the correlation curve (diagram) and the report will be saved. Otherwise, the sound data
will also be stored in universal WAV format. The saved sound data can be called up at any time
again, played back and correlated once again.
