Sanden SN3500, Installation Manual

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Appendix A: Post-Installation Procedures
82005-IM-K Sandel SN3500 Installation Manual Page 7-5
CAL N
CAL E
CAL W
CAL S -25.0° - 25.0° Calibration settings for fluxgate input.
See below.
7.1.3.1 Compass Calibration (Applies to installations using a fluxgate input)
When a flux gate is first selected the quadrant and peaking adjustments will be
automatically set.
The magnetic heading shown in the value field at the top of the page should be within
+/-20

of the aircraft’s wet compass reading. The magnetic heading reading should
also increase and decrease as appropriate when the aircraft is turned. If this is not
the case, the following troubleshooting procedure can be used to diagnose fluxgate
problems:
a) Align the aircraft to north. Set the CAL settings to 0.0

. Adjust the
quadrant setting until the magnetic heading is +/-20

of north. If it is not
possible to come /-20

of north then the XYZ connections the
fluxgate may actually be ‘YZX’ or ‘ZXY’. Take all three wires off the
fluxgate and move them one terminal ‘clockwise’ and retest as above. It
may be necessary to repeat this step. Once the magnetic heading reads
/-20

of north then the correct Z leg has been identified and should
not be changed
Note: When installing to existing wiring, ensure that the fluxgate center tap
that exists on some Honeywell/Sperry and Collins fluxgates is not
connected.
b) Ensure that the compass card rotation is correct by observing that the
magnetic heading reading increases/decreases properly as the aircraft is
turned. Reverse the XY inputs from the fluxgate to correct for reverse
rotation if necessary.
Compass calibration is completed by aligning the aircraft at each cardinal heading
and adjusting the corresponding calibration value until the magnetic heading reading
observed on the compass maintenance page, matches the actual aircraft heading.
After the four cardinal points have been adjusted and verified, a final check of the
systems should be done by power cycling the SN3500 into normal mode and
ensuring the compass rose is correct for each cardinal heading.
NOTE: Changes to the compass calibration settings may take up to two minutes to
take effect when observing the compass card in normal operational mode. Therefore
It is recommended to make these calibration adjustments on the compass
maintenance page where the compass readings are instantaneous and not affected
by the slaving logic in the SN3500.