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MIDAS DWR Directional Wave Recorder
The MIDAS DWR Directional Wave Recorder replaces the old Model 730D instrument, and represents a significant advance in PUV wave recording technology. As well as the standard non-directional data available from the MIDAS WTR, the MIDAS DWR also performs full onboard directional data analysis, allowing real time directional information at an unsurpassed 2° resolution. The unique features of the MIDAS DWR make it the most cost-effective solution to directional wave monitoring requirements in all shallow water coastal applications.
Valeport Wave Recorders are "PUV" type that use Linear Wave Theory to analyse the pressure and current oscillations
Valeport MIDAS DWR Directional Wave Recorder, and the MIDAS WTR Wave & Tide Recorder. The name “MIDAS” is used to describe all of Valeport’s premium products, utilising common system components and advanced sensor technology to provide a range of the highest quality oceanographic and hydrographic instrumentation.
Both devices use the long-established principle of Linear Wave Theory, measuring the pressure variations caused by waves and converting them into actual wave data. In addition, as a “PUV” type Directional Wave Recorder, the MIDAS DWR calculates the direction from which the waves are coming by measuring the current oscillations caused by wave motion.
The basic principles of wave measurement rely on the understanding that a wave is not a single defined entity, but the result of a series of individual waveforms superimposed on top of each other, all with different wavelengths, frequencies and amplitudes. Measurement of the wave activity therefore requires measurement of the pressure (and current) variations for a period of time, then “decomposing” the pattern into the constituent waveforms before analysing them and interpreting the data as a set. The key stages in these complex calculations are described in Section 8. The basic instrument functionality is therefore to measure a burst of data for a period of time (typically several minutes), then to perform the calculations; all raw and calculated data is available for on board storage or real time transmission using a variety of standard methods.
The MIDAS DWR & WTR are fitted with a pressure sensor (resonant quartz or strain gauge) to measure the pressure variations; the MIDAS DWR is also fitted with a Valeport electromagnetic current sensor to measure the current oscillations, with the direction referenced to an internal flux gate compass. In addition both instruments are fitted with a PRT temperature sensor as standard, and optional conductivity and turbidity sensors may also be fitted to the standard package. If the deployment situation allows, atmospheric pressure, wind speed and wind direction sensors may also be added to the package.
The instruments are supplied with Valeport’s own WaveLog Express PC software for instrument setup, data extraction, and display of all data (real time or logged).
MIDAS DWR Directional Wave & Tide Recorder
0730035 Directional Wave and Tide Recorder fitted with 0.01% accuracy, 100 decibar, piezo-resistive pressure, PRT temperature sensor, 11cm discus EM sensor and 64Mbyte FLASH memory. Supplied with 32 x alkaline D cells in removable battery carousel, WaveLog Express Windows software, 3m "Y" lead, RS232 / USB adaptor, tool kit, switch plug, manual and system transit case.
0730036 Directional Wave and Tide Recorder fitted with 0.04% accuracy strain gauge pressure transducer (specify 35, 50 or 100dBar range), PRT temperature sensor, 11cm discus EM sensor and 64Mbyte FLASH memory. Supplied with 32 x alkaline D cells in removable battery carousel, WaveLog Express Windows software, 3m "Y" lead, RS232 / USB adaptor, tool kit, switch plug, manual and system transit case.
NOTE: Maximum operating depth for wave monitoring is 20m.
Direct Reading Communications Options
0400005 FSK communications option, for use with up to 6000m cable. Comprises additional pcb inside instrument & surface adaptor unit with interface to PC and external DC power.
Accessories and Spares
0400011 Valeport Conductivity Sensor, pressure balanced bulkhead mounted type.
0400021B Seapoint Turbidity sensor, bulkhead mounted. Supplied with Valeport calibration pot.
0400021BI Interface for Seapoint Turbidity sensor (bulkhead type), including calibrated pcb (FTU).
0730037 Stainless steel seabed mooring frame for MIDAS WTR / DWR
0730EA32 Spare Battery Carousel (32 x D cells, not included)
0400EA4 3m "Y" lead, instrument to PC/ power supply (Subconn type).
0400EA3 Subconn switch cap assembly
CAUSB USB to RS232 Adaptor lead
TKDWR/WTR Toolkit & Spares for MIDAS WTR / DWR, includes screwdriver, allen key, o-rings, grease and silt trap oil
0730040 Silt Trap Oil (50ml Dow Corning 704) & Syringe
TC500 Transit case lined