声学多普勒海流剖面仪Rcm_11

AANDERAA

FIELDS OF APPLICATIONS AANDERAA INSTRUMENTS

temperature range ensures proper operation in the Polar Regions.

In-line Mooring

the mooring line and the instrument package to the surface.

Comparing the RCM 11 with a WMCM in a short mooring

may be compared to older measurements.

found in various publications from Woods Hole.

Tto be low.

included a period of the deployment where the VMCM was not stalling due to speeds below impeller threshold. One of the RCM 11 was configured to Burst mode (red line), while the other to normal mode (green line). It is seen that the current speed [m/s] measured with two RCM 11s are very similar, hence the short mooring has not moved significantly during the deployment time. This is best illustrated in the lower graph, were the WMCM results have been removed, and the graph covers the entire deployment time. The results also show that two RCM11 obtains the same results, even if they have not been specifically calibrated. As such it is a proof of that the intrinsic "calibrated by design" approach used is correct.

A series of measurements were taken by one of our customers in august 2000.

The graph to the right shows the current speed measured with an RCM 11 over a 3 day period at 1400 meters depth.

The measured values, between 0,5 and 12cm/s, are almost without any noise even though the current speed was only a fraction of RCM 11’s capability. Notice also the tidal influence on the measurements even at 1400 meters depth.

SENSORS AANDERAA INSTRUMENTS

Doppler Current Sensor 3820

The sensor utilizes the well-known Doppler Shift principle as the basis for its measurements. The sensor transmits acoustic pulses of 2MHz into the water in sequence. As the sound propagates, small particles or air bubbles in the water reflect a portion of the energy. The back-scattered energy from the area between 0.4 to 2,2 meters from the sensor is picked up by the transducers and analyzed to find any change in frequency. The DCS 3820 employs state-of-the-art signal-processing and computer tuned electronics. The unit achieves low static noise even in waters with scarcely any backscatters. As such the DCS 3820 is well suited for deep sea measurements when the sea current is expected to be low.

The current direction is found by tak ing the measurements along two orthogonal axes, x and y. These measurements are compensated for tilt by use of an electrolytic tilt sensor and referred to magnetic North by means of an internal Hall-effect compass. A microprocessor com putes vector averaged current speed and direction over the last sampling interval. The sensor output is the Aanderaa standard SR10.

The sensor has an OD of 120mm, is 100mm thick and has a 10-pin receptacle at its lower end. The sensor is fastened to the instrument by an 86 mm high sensor foot. Four piezoceramic acoustic trans ducers are placed 90° apart around the circumference of the sensor that is molded in a polyurethane material.

Conductivity Sensor 3919 A/B

This sensor measures the conductivity in the water by use of an inductive cell principle. This provides stable measurements without electrodes that are easily fouled in the field. The conductivity sensor outputs data in both RS232 and Aanderaa SR10 format. The RS232 outputs the conductivity in mS/cm. The SR10 provides two output channels. The user may configure the range on both SR10 outputs, which offers the possibility to zoom in on the range of interest. Depth capacity: 6000m.

Turbidity Sensor 3612

This sensor measures the turbidity of the water by use of back-scattered infra red light. This measurement is known to have good correlation to the amount of suspended matters and can be used to monitor sediments, algae, or particle pollution. Three light emitting diodes and a photo diode are pointing to a common center at an angle of 15°. Once every measuring cycle the light emitting diodes send out light and the reflected light from particles in the water is picked up by the photodiode. The sensor is shaped as a small cylinder molded in polyurethane material. Depth capacity: 2000m.

Pressure Sensor 3815

The sensor is shaped as a small cylinder molded in Durotong polyurethane. It measures the absolute pressure by means of a piezoresistive bridge. One measurement is taken for every measure ment cycle. This is an analog sensor, and the output is the Aanderaa standard VR22 signal.

Oxygen Optode 3830

This Oxygen Optode measures dissolved oxygen in fresh and sea water by using the latest technology. The principle of measuremens is bades on the effect of dynamic luminecence quenching (lifetime based) by molecular oxygen.The range is 0-16mg/l with accuracy ±0.3mg/l or 5 % whichever is greater. The output from the sensor is an SR 10 signal.

ELECTRONIC BOARD AANDERAA INSTRUMENTS

RCM11 Top end plate with a selection of sensors and wireing to the Electronic Board. Note! The Oxygen Optode 3835 shown in the picture can only be used down to 300m, for greater depths use the 3830 version.

DATA MANAGEMENT

AANDERAA INSTRUMENTS

Data Reading Program 5059

is a software program from Aanderaa used to download DSU 2990 data to a Personal Computer. The program is based on the latest software technology and is designed for use with Windows 95, Windows 98 and Windows NT.

In addition to downloading and exporting of DSU data, it can also be used for data analysis. The 5059 includes extensive charting and analysis facilities, and the resulting analysis graphs may be exported to programs such as Microsoft Word and Excel. The modern user interface, including

drag & drop facilities, and an extensive built-in Help system makes the 5059 easy to use.

A sensor, station and instrument library allows you to build up a library holding configuration and calibration sets for all your Aanderaa instru ments. A limited version of this program is supplied free of charge. The full version is available at a moderate cost. Please contact the factory or visit our web site to obtain a 30 day fully functional trial version. The program is delivered on a CD with a comprehensive operating manual.

Engineering Data graph from RCM 9 serial. no. 565

Representative’s Stamp

Virtual sensor handling, Salinity

PO BOX 34 SLÅTTHAUG 5851 BERGEN, NORWAY

Latest version is on the Internet

NESTTUNBREKKEN 97 TEL. +47 55 604800 5221 NESTTUN, NORWAY FAX. +47 55 604801

E-MAIL: [email protected]

WEB: http://www.aanderaa.com