Autonnic A5022 Manuale d'uso - Pagina 8

Sfoglia online o scarica il pdf Manuale d'uso per Attrezzatura marina Autonnic A5022. Autonnic A5022 12. Fluxgate compass

shifting the centre from the origin and induced magnets ('soft') modify the circle into

an ellipse. The results of our investigation show that there is always a residual

error due to the fact that real magnetic objects do not behave exactly according to

the model outlined. Autonnic is aware that the need for a constant angular velocity

is onerous but the benefit is that it provides a very low residual error – less than

0.5°.

Note that the calibration is different if the unit is mounted upside-down.

Calibration must always be done with the unit in its final mounted position. The essential

point of the calibration is remove the influence of external magnetic components in

the vicinity – the nearby pieces of iron and steel –so it is essential that these remain

unchanged after calibration. If any significant iron component is altered – such as

the installation of new equipment or replacement of equipment such as winches or

engines – then the calibration must be re-done.

4.3 Terminating a bad calibration

If the process is faulty in any way – such as would happen if the manoeuvre cannot be

completed, the process can be terminated by the NMEA command listed and the

original factory default (linear) table is restored. Alternatively this can be done by

pressing both Switches together for at least 1 second.

NOTE that there should be a delay of at least 5 seconds after termination before a new

calibration process is initiated.

4.4 Setting reference NORTH heading

Switch 2 (and also a NMEA command) is provided to set 'zero'. The A5022 should

first be auto-calibrated

then be aligned to North

When the A5022 is fixed in place and connected it can be calibrated as described

above. Choose a calm day and a region of water where there are no currents. Set

the boat turning to left or right at a slow rate and fix the wheel or tiller. Then, when

the turning is steadily under way, press the auto-calibrate button and watch the

LED.

When calibration is completed the boat can be on its way and the next task is to set

North. This is best done by identifying transits on a chart and heading the boat on

the transit. Again this should be done in the same conditions so that the heading

can be lined up on the transit and maintained while the set-zero button is pressed.

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