Auto pilot makes GPS map shift

I

Irish Mist

Well-known member
Joined
Apr 25, 2012
Messages
1,175
Fluid Motion Model
C-288 C
Hull Identification Number
FMLT2922K011
When I turn on my auto pilot my map on the GPS shifts and my heading indicator on the map and the boat icon are askew I seem to remember a post about a fix for this but can't find
Thanks
Mark
 
I seem to remember that you either need to do a calibration routine, which is explained in the manual or the gyro (black ball in the cave) may have been turned somewhat and needs to be turned back to its original position. Maybe someone else's memory is better.
 
I did the ball spinning before but I thought there was something else But I may be wrong. I am going to give that a go again
Thanks
 
You should try to do it with little wind, and no current. then run the boat on a straight line and turn the ball until the heading on the autopilot matches the compass. Definitely a two person operation. Running on a east west direction gives you a more stable compass reading so try that as well. Of course I am assuming the compass has been swung.
 
Make sure the area around the gyro compass does have anything stored next to it. Such as food cans, etc. Don't ask me how I know.
 
So I should move my magnet collection to another drawer 🙂
Thanks will give it a shot next time out
 
As many of us use the cave as a closet,pantry catch all, how far do you think "stuff made of metal" should be away from the mystical black ball?

I appreciate the info...
 
These may help you... there was a lot of discussion about this just before the Bremerton meeting last year. Garmin was at that meeting for two days helping people sort out any issues they had. In my case, they sorted out my 'boat icon angle' issue when navigating a 'Safe Course'. I cannot detail exactly what Garmin did, but their basic approach was to re-calibrate the Auto Pilot's compass. The manual explains this somewhere and you have to use the "Wizard" process. The "Wizard" menu was previously accessed by pressing two of the Auto Pilot's buttons at same time.... but with latest Garmin 5212 firmware updates I believe this changed... I will try and find the details later in my Garmin manual which is on the boat.

On our R-25, the Auto Pilot's compass is under the V-berth and on the centerline.

http://www.tugnuts.com/viewtopic.php?f=2&t=3004

http://www.tugnuts.com/viewtopic.php?f=5&t=2928&start=15

http://www.tugnuts.com/viewtopic.php?f=4&t=2945

http://www.tugnuts.com/viewtopic.php?f=2&t=492

http://www.tugnuts.com/viewtopic.php?f=5&t=2928
 
I recall that "stuff made of metal" should be atleast 2 feet away from the gyro. "Stuff made of metal" means metal which is attracted by a magnet.
 
Osprey":2kvu8z9x said:
I recall that "stuff made of metal" should be atleast 2 feet away from the gyro. "Stuff made of metal" means metal which is attracted by a magnet.
Click to expand...

Hmmm, if the Auto Pilot's compass / gyro for the R-27 is in the cave that 2 feet gets awfully close to the engine ! 😉
 
I think that you may be confusing the wet compass with the gyro, but then again I could be wrong. As far as I know from my flying days the wet compass is magnetic sensitive and the gyros that were in the plane were ether run by electric or vacuum. The gyros were more reliable because they were not subject to lag or other interferences that you get with your wet compass. Therefore metal should not affect a gyro.
 
The round ball is the CCU, Course Computer Unit. It contains a magnetic heading sensor and also senses rate of turn. It is connected to the NMEA 2K bus, shadow drive sensor, ECU (Electronic Control Unit that is connected to the pump), and GHC display. I do not believe it contains a typical gyro. Per the installation manual it is supposed be be 24 inches from magnetic sources. Per the autopilot installation manual there are a couple of procedures to tune it for heading, a compass calibration and setting North. Both are done with the wizard in dealer installation mode on the GHC display. The compass calibration is a steady clockwise turn so the CCU can calibrate out magnetic deviation, these are errors caused by magnetic fields in the boat. The North setting procedure requires a period of straight cruising, about 45 seconds, the CCU uses the GPS data on the NMEA bus to determine the actual heading and sets North in the ECU. (you can cruise in any direction as long as it is straight). Obviously both of these are best done in light current/wind conditions.
In my tug the 5212 uses the heading information from the CCU to set the display up heading. It is not using GPS heading while the autopilot is powered on. While at anchor I have powered off the autopilot, after a short period the 5212 alarms that it has lost its heading source. I believe it swithes to GPS heading at this point, which causes wild display rotations while at anchor as the boat slowly swings. There is probably a 5212 configuration to control the default heading information source.
If you see different display errors on the 5212 map at different headings that are not explained by wind/currents then you should try running the calibration procedure on the autopilot, the magnetic fields in your boat may have changed since this was last done.
If the error is constant in a particular direction at any heading then the North setting in the CCU is off a bit, there is a manual tune process you can use in dealer configuration mode to adjust this (Fine heading adjustment), or run the set North wizard. Or you can rotate the CCU a bit, but I find it easier to use the GHC display and adjust it electronically.
The autopilot installation manual describes these procedures.

Howard
 
Howard: Excellent information. What you described is pretty darn close to what the Garmin guy did for us on our R-25 at last years Bremerton meeting. This not only re-calibrated things but also corrected an issue of my boat icon sliding/crabbing along the Safe Course line on the Chart Plotter that the auto pilot was instructed to follow.

The wizard process described in the manual may or may not be correct as I believe a recent 5212 firmware/software upgrade made this process simpler for us. Part of this simplification was that it became unnecessary to press 2 buttons simultaneously to get the attention of the Wizard...

Thanks for posting the details.... 🙂
 
Yes, thank you everyone for your imput.. I found the little ball when I first got the boat and of course had to check it out as who would have thought a little ball behind a drawer could have any important function.. Wrong!! Anyways it is not too far out of wack so I'm sure I will have it perfect soon
Thanks
Mark
 
Thanks for the info Howard. I see my assumption that it is a typical gyro was incorrect. I guess I should move my suit of armor hanging on my cloths rack! 😀
 
Anyone know where the CCU is located on a R-31. My autopilot was not working and I pulled plug on both my GHC-10 units. They now find the autopilot controller but I think the heading may be whacked. How do u enter wizard mode? I don't see that under setup as an option
 
coreychamness:

See also... http://www.tugnuts.com/viewtopic.php?f=5&t=2928&p=21371&hilit=wizard#p21371

RE: GHP 10's Wizards... I followed the Garmin's instructions using their "GHP 10 Marine Autopilot System Installation Instructions" guide and found a few things missing that one has to do in order to get at the Wizards...

To get the Wizard display to show one must

1. Not have engine running Garmin does not say to do this.
2. Power off the GHP 10
3. Press the right most two buttons (center one and right most one) while also pressing the power button
4. Wait a short while until the Heading screen appears
5. Now select Menu->Setup
6. If the option for Dealer Autopilot Configuration is shown then you did the above correctly

When running the Dockside Wizard configuration and getting to the RPM Source selecting the NMEA 2000 cannot be done UNLESS you have the engine running. This is not mentioned in the Garmin's instructions.

BTW... I changed the Lock to Lock option from 4.0 to 4.1 for my R-25. I know that my wheel turns a tad more than 4 full turns.
 
coreychamness":2whzjjqr said:
Anyone know where the CCU is located on a R-31. My autopilot was not working and I pulled plug on both my GHC-10 units. They now find the autopilot controller but I think the heading may be whacked. How do u enter wizard mode? I don't see that under setup as an option
Click to expand...

If it has not been relocated already (Might need to be) it is behind the top drawer of the drawers in the cabinet under the center post behind helm under galley counter.

I do not remember how to get into the wizard. Ronnie Gonzales may chime in here and tell you. Do not put your silverware in the top drawer. Oops I see Baz already has...thanks Barry,
 
Thanks very much for the information about getting into wizard mode and the R31 location. I will check behind the drawer - I do not recall seeing it under there. Our metal flatware is definitely in the top drawer. I am not sure I understand what difference it makes regarding the lock-to-lock number of turns since the steering pump at the helm is not involved in a turn by the autopilot.
 
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