Calibration.. again..

[PaddyB]

I keep getting some of the calibration points not on the sphere - what could cause this?? It's quite close to a Sestral Moore compass, could the magnets around the base of the compass be a cause? 

thnx

[seandepagnier]

yes

Please try mounting it somewhere else and try.

compasses are the worst because as the compass rotates it changes the distortion making calibration near impossible. Fixed magnets would only give an offset which can be compensated for, but large offsets are not ideal either.

[PaddyB]

any idea what sot of distance would be needed?
Right now it's about 30Cm from the compass

thnx

[seandepagnier]

30 cm is probably way too close for an actual compass if it is the type that floats in oil in a glass dome thing??

Honestly I would suggest putting it really far away, like at least 3 meters, then try it and make sure it is working. Then try moving it closer if you want to and from experimentation determine the distance needed... Sorry I cannot give a better response because it really depends on the strength of the magnet in your compass.

If you do find out the minimum distance it would be interesting to know your results.

[PaddyB]

The compass is one of these for a steel boat with compensating magnets in the base.


Steel boat so I assumed without thinking the sensor would need to be outside but I could try various places down below & just see how it goes, thanks!

[PaddyB]

Seems much better, think this is good enough to calibrate? Every time I pull up the anchor I get involved with saioing & forget to do a 360



Increasing the D & DD certainly made a big difference to tracking! As the pcnautic actuator is quite far towards the front of the tiller it actually only moves about 10 deg but has loads of torque on the large rudder, is good enough to still be useful but maybe I should move it back a bit.

[seandepagnier]

Yes, generally you hope for +- 30 degrees, although 15-20 might be good enough for course holding. For tacking in various conditions more rudder angle may be useful.