YSI SonTek ADVField, Technical Documentation Manual

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SonTek/YSI
ADVField/Hydra Operation Manual (September 1, 2001) 85
5.6. Mounting and Handling the Sensor
Before starting routine data collection, we recommend building a mounting bracket that clamps
onto the conditioning module. Simple mounting arrangements often use hose clamps attached to
a rigid bar. For these, cover the conditioning module to protect it from damage. More complex
mounting arranges may use pillow block clamps to secure the conditioning module and may be
coupled to traversing systems for measuring at different locations. The overall design will vary
considerably depending on the environment in which the ADV is to be used and the forces to
which the instrument will be exposed. The following list gives some basic advice for mounting
and handling the ADV.
•
All three acoustic receivers and the transmitter must be submerged for proper operation.
•
The path from the acoustic sensor to the sampling volume, and the area around the sampling
volume, should be free from obstructions. Objects in this area can cause both acoustic inter-
ference (if in or near the acoustic travel paths) and can introduce flow distortion in the sam-
pling volume.
•
Take care not to damage the acoustic sensors. These are the most delicate part of the ADV. If
you suspect that the sensor may be bent or damaged, run
ADFCHECK
. See §5.11 and the
ADV-
Field Software Manual
for details.
•
Clean the acoustic elements to remove deposits of seeding material, bubbles, or other mate-
rial. For field deployments, biological deposits can be removed with a stiff brush (non-
metallic) without damaging the sensor. Carefully remove barnacles by scraping with a knife
or by soaking the probe in vinegar.
•
The system can be operated with the acoustic sensor out of the water without damage, al-
though the velocity data will be meaningless.
•
Make sure a zinc anode is installed and in good condition when operating the ADV in salt
water. If you have any concern about the condition of the zinc anode, replace it. Always rinse
the probe in fresh water after use in salt water.
5.7. Optional Integrated Sensors
The ADVField can include a variety of integrated sensors, both internal and external. The sensors
are connected to the ADV using special interface cables or boards. Other sensors may be inte-
grated using analog output voltages. Depending on the sensor, input power may come from the
ADV or may require a separate power supply. A few of the more common external sensors are
described below. For details on available sensors and configurations, contact SonTek. Some of
the optional sensors available for use with ADVField systems, include:
•
Temperature sensor – Used for sound speed corrections in long deployments with large tem-
perature fluctuations. Internal or external CTD types are available. Typical configurations are
described in §4.8.
•
Pressure sensor – Provides simultaneous pressure and 3D velocity measurements (PUVW for
directional wave spectra). Internal, external, analog (strain gage), and frequency (resonance)
types are available. Typical configurations are described in §4.8 and §4.9.
•
CTD – Provides high-quality conductivity, temperature, salinity, and pressure data. Typical
configurations are described in §4.10.
•
OBS, transmissometer, conductivity, etc – Many of these types of sensors can be integrated
using analog output voltages. Common applications include OBS or transmissometer data for
suspended sediment studies. See §4.11 for more information.