Magnetic Deviation Calibration | Maretron DSM250-01 manual

The choices that are offered are “Normal Installation” (default), “Backward Installation”, “Upside-Down Installation”, or “Upside Down and Backward”.

6.22.4Label

This menu item allows you to set a text label for the device. This text label will help you to identify a particular device when you have more than one of the same type in the system, and appears when selecting devices in both the DSM250 and in N2KView.

See section 3.3.4 for details on how to enter a textual value.

6.22.5Magnetic Deviation Calibration

The DSM250 is capable of performing magnetic deviation calibration on a Maretron SSC200 solid state compass. The Rate of Turn Offset Calibration (section 6.22.8) should be done before the Deviation Calibration. The first screen (Figure 172) gives instructions for performing the procedure. First, begin to turn the boat in a slow circle (either clockwise or counter-clockwise) at about 3 to 12 degrees per second.

Figure 172 – SSC200 Magnetic Deviation Calibration Start Screen

Once you have begun the turn, press Begin ( ) to start the calibration procedure. If you do not wish to perform magnetic deviation calibration at this time, press Abort ( ), and the currently stored deviation tables will be retained. If you are in a large vessel, it may be difficult to turn the vessel in a small enough circle to avoid significant centrifugal force applied to the compass during magnetic deviation calibration. This can cause the built-in tilt sensors inside the compass to mistakenly believe that the compass is tilted during the magnetic deviation calibration, which can adversely affect the quality of the magnetic deviation calibration, especially in northerly latitudes where magnetic inclination (magnetic dip) is higher. If this is the case, instead of pressing the Begin ( ) key, press the No Acc( ) key. This will cause the compass to ignore its tilt sensors and assume that the compass is level to the earth’s surface during the calibration. You must keep the boat level during calibration if you choose this option. After you press the Begin ( ) key or the No Acc( ) key, a status screen will appear (Figure 173).