YSI SonTek ADVField, Technical Documentation Manual

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SonTek/YSI
6 ADVField Operation Manual (September 1, 2001)
•
The sampling volume is the volume of water ( ≈ 2 cm
3
) in which the ADV makes velocity
measurements. This volume is nominally located 18 cm from the acoustic transmitter.
•
The probe X-axis is defined by the direction of receiver #1, which is marked with a small in-
dentation on the sensor head. When looking from the sampling volume towards the acoustic
transmitter, the receivers are numbered 1, 2, and 3 moving clockwise from #1. (See §5.1 for
coordinate system details.)
•
The signal-conditioning module is a cylindrical housing with internal receiver electronics. The
acoustic sensor head is mounted at one end of the housing, while the other end cap is con-
nected to a high-frequency cable using a 16-pin wet-mateable connector. The temperature sen-
sor potted inside the sensor head is used for sound speed corrections in long deployments with
large temperature fluctuations.
•
The high-frequency cable to the processing module carries analog signals from the probe to
the digital processing electronics. This cable is highly sensitive to noise and should not be
modified, extended, or shortened without instruction from SonTek. The cable is connected to
the signal-conditioning module using an underwater mateable connector.
•
The stainless steel ADVOcean probe has a total length of 33 cm (13.1 in), a housing diameter
of 4.5 cm (1.8 in), and a maximum arm diameter of 20 cm (7.8 in) for the circle about the ends
of the three receiver arms. The ADVOcean probe with the plastic conditioning module hous-
ing has the same dimensions, except the housing diameter is 5.3 cm (2.1 in).
5-MHz ADVOcean Probe Configuration with Optional Sensors
: The 5-MHz ADVOcean probe
can include up to two optional built-in sensors: compass/tilt and pressure. These sensors are
mounted in a modified signal-conditioning module (Figure 6). The compass/tilt sensor allows the
ADV to report velocity data in Earth coordinates (East-North-Up or ENU), regardless of instru-
ment orientation. The pressure sensor with optional depth ranges and accessories gives simulta-
neous pressure and 3D velocity measurements (PUVW for directional wave spectra).
•
The ADVOcean probe consists of an acoustic sensor head (which includes a temperature sens-
ing thermistor), a signal-conditioning module with the optional sensors, and an underwater
mateable connector to a high-frequency cable. The probe serial number is engraved on the
housing near the acoustic transmitter.
Figure 6 – 5-MHz ADVOcean Probe with Optional Sensors
Acoustic receivers (3)
Acoustic transmitter
Acoustic
sensor
assembly
Sampling
volume
Signal
conditioning
module High-frequency cable (to Processor)
End Cap
Anode
Underwater mate-
able connector
Pressure
sensor
Probe’s X-axis
(aligned with
Receiver #1)