YSI ADV6600 - Manual (Page 151)

Section 11. Troubleshooting
ADV6600
Y S I
Environmental
Page 141
Excessive Noise
If the electronics noise level is more than 10 counts above its normal level (60-70 counts), it may be
a sign that something is wrong with the sensor or installed environment. The noise level may also
be higher than normal because of external electromagnetic interference, or because water has
condensed on the receiver electronics. Coil any extra probe cable to minimize the noise.
High signal strength past the boundary
If the signal strength does not fall off rapidly past the boundary, the additional acoustic noise can
potentially increase the noise in velocity measurements. This additional acoustic noise is most
commonly seen in small tanks, particularly those made of acrylic or glass. To improve the readings,
cover the boundary with a piece of cloth, a rubber mat, or a sheet of acoustic-absorbing material.
11-3.2. Noisy Velocity Data
If the velocity data from the ADV6600 does not appear reasonable, the following list may be helpful
in establishing the source of the problem.
• Verify there is enough scattering material in the water. If necessary, seeding material can be
introduced to increase signal strength. See Section 11.3.3 below
• Run a diagnostic check on the ADV as described in Section 5. This will address all aspects of
ADV operation, especially interference, signal strength (scattering/seeding issues) and probe
operation.
• Verify the velocity range setting is appropriate for the operating environment.
• Verify the probe is not fouled with debris.
• Verify the ADV6600 mounting is stable and that instrument motion is not causing noise in the
velocity data.
• Look at the compass/tilt sensor data (if installed). Look for large tilt values or how compass/tilt
data changes with time to see if the instrumentation has moved.