Raymarine i70 Installation Instructions Manual

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Raymarine i70 Installation Instructions Manual Manual pdf 39 page image

5.5 Speed calibrationSpeed calibration involves aligning the log speed (Speed ThroughWater) to the Speed over ground (SOG), under calm tide conditions.The object of speed calibration is to ensure that the speed readingsat the instruments are true indications of the vessel speed, ideallyover the speed range of the vessel, i.e. from stationary to top speed.In order to take into account the changes in water-flowcharacteristics across the hull, for different speeds, it is advisableto carry out speed calibration at as many speeds as possible. Thisis particularly important for planing vessels.Conventional Speed transducers have a maximum of five calibrationspeeds, and smart transducers (e.g. DST800) have up to eight.The correct calibration at each speed is achieved by applying acalibration factor to the indicated speed reading.In order to achieve accurate results, speed calibration must becarried out in calm conditions with zero tide and zero current.Calibrating speed (conventional transducers)If you do not have a GPS connected to your system to obtain SOGdata from please proceed to the Calibrating speed manually section.• You will need an accurate speed over ground (SOG) value, e.g.determined from a GPS connected into your system.• You will need to be underway, with sufficient space to maneuverunhindered.• Conditions should be calm with zero tide and zero current.Note: It is important that there is no tide. The affect of tidalcurrent would be to prevent an accurate speed calibration.1. From the Transducers found page highlight and select Speed.2. Highlight and select Speed Calibration.You will see 5 calibration speeds provided by the system3. Calibrate each speed setting as follows, starting with the lowest:i. Highlight and select the required calibration speed.ii. Adjust your vessel speed until the SOG is at the desiredcalibration speed.iii. Adjust the calibration factor using the UP and DOWN buttons,until the SOG and Speed reading are the same.iv. When complete press SAVE to save the settings and returnto the Speed Calibration menu.4. Repeat this for each calibration speed valid for your vessel.Speeds which fall outside your vessel’s capability need not becalibrated.Calibrating speed (smart transducers)A DST (Depth, Speed, Temperature) smart transducer is calibratedto a set of 6 default speeds. These provide acceptable transducerperformance in most circumstances. However you can insert anddelete different calibration speeds, up to a maximum of 8, to providea range of speed values to best suit the way your vessel will be used.• You will need an accurate Speed over ground (SOG) value, e.g.determined from a GPS connected into your SeaTalkng system.• You will need to be underway, with sufficient space to maneuverunhindered.• Conditions should be calm water with a slack tide.Note: It is important that there is no tide. The affect of tidalcurrent would be to prevent an accurate speed calibration.You can set up to 8 calibration points across the full speed rangefor your vessel.1. From the relevant conventional or smart transducer pageHighlight and select Speed Calibration.The screen will display the list of speeds to which the transduceris calibratedSystem checks 39