YSI ADV6600 - Manual (Page 53)

Section 4. Calibration and Diagnostics
ADV6600
Y S I
Environmental
Page 43
To record real-time beam check data for later playback:
• Start the display of real-time data as described above.
• Click Record. You will be prompted for a file name and storage location.
• Use the menu and control items to alter the display of data as desired (i.e., recorded data is not
affected).
• Click Pause or Stop to interrupt or end data collection.
To playback previously recorded beam check data:
• Click Open to select a previously recorded beam check file.
• Click Replay (or Pause) to start the playback of data.
• Use the menu and control items to alter the display of data as desired.
The Beam Check window also shows a tabular output of diagnostic parameters for each of the three
acoustic receivers.
Noise
This gives the electronics noise level for each receiver, determined by the signal
strength when the ADV6600 is not receiving any return reflection from the water.
This should match the signal strength for the flat portion of the graph beyond the
boundary. Normal noise levels are 60-70 counts.
Peak Position
This is the location of the center of the peak for the sampling volume for each of
the three receivers. The position should be approximately the same for each
receiver; variations of 5 to 10 counts are typical
Peak Level
This is the height of the peak for the sampling volume for each of three receivers.
Peak level varies depending on the amount of scattering material in the water.
The peak level should be approximately the same for each receiver; variations of 5
to 10 counts are typical
4-3. Calibrating the Compass
The compass which is standard in each ADV6600 is used to compensate for the effect of sonde
movement on velocity readings during deployment. Before you use your ADV6600 in field studies,
you must calibrate the compass to make sure it is functioning properly. The compass calibration is
designed to minimize the effects of ambient magnetic fields on compass data and its subsequent
effect on velocity readings. It is recommended that a compass calibration be performed at the site
before each deployment and after moving the ADV6600 to a different environment or mounting
apparatus. If possible, perform the compass calibration with the ADV6600 installed in the
mounting frame that will be used for deployment. However, to become familiar with the
calibration procedure, YSI recommends that you first carry out a compass calibration under more
controlled conditions in the laboratory. Use the following steps to perform the calibration routine.