[CA] [CA11] Evolution sensor core and AC interference

[ddfour1]

My recently installed Evolution AP works great. however, I ran my air conditioning dockside for the first time last week. The next trip out my AP heading was off by 180 degrees. Because the AP had been working without issue for several trips and the only thing that changed was the usage of the air conditioner, I am assuming that caused the problem. I unplugged the sensor core spur cable from the system and re-plugged it in and that fixed the heading issue.

My sensor core is a little over 3' away from the AC unit itself so I hope that distance is sufficient. However, there is a wiring run containing the power line for the air condition that my sensor core is within 3' of. About 18" away.

As I go about trying to find a new location, here are my questions:

1) Is it a problem that the backbone cable to the sensor core shares a wiring run with AC power lines?

2) If 1 is not a problem, I assume the core itself needs to be at least 3' away from that power line run in addition to that distance from away from the air conditioner itself, correct?

3) The power lines are run inside a PVC tube. Is there any shielding material I can cover the PVC tube with to minimize the effects of the AC on the sensor core? The location I have now is about as ideal as its going to get.

Thanks

Dave

[Chuck - Raymarine - Moderator]

Welcome back to the Raymarine Forum Dave,

I see a couple of possibilities here. The first is that air conditioning unit (or some other nearby device) has an excessively strong magnetic field associated with it.
Please click here to view a FAQ addressing this subject. The referenced FAQ describes one third party mobile app which may be used to detect magnetic field strength in the area of the EV-1 CCU. As indicated within the referenced FAQ, it is recommended that all electrical devices onboard be operated to determine their effects and/or the effects of the cables powering these devices upon magnetic north sensing devices. It would be recommended that the EV-1 CCU's installation location again be tested for sensed magnetic field strength and if found to be excessive, that the EV-1 CCU or device / wiring producing the magnetic field be relocated. It is unlikely that the proximity of the power cable to the backbone cable is responsible for the reported issue. As indicated within the referenced FAQ, equipment cannot be shielded from magnetic fields ... physical separation must be employed.

The second possibility (may be in combination with the first) is that a surge associated with powering the high current demanding equipment has affected the memory of the EV-1 CCU. Please click here to view a FAQ addressing this subject. After applying the correct isolation product for your application, then it would be recommended that the EV-1 CCU's installation location again be tested for sensed magnetic field strength. After doing so, it would be recommended that a Pilot Factory Reset, Dockside Wizard, and cruise to detect magnetics be undertaken again.

[ddfour1]

Thanks Chuck. I turned on all of the AC-powered equipment (including air conditioner) on my boat and took a measurement with the iNstall Magnetometer app. At the location of my sensor core I was measuring very little local field. For comparison, I also took a measurement at my MFD and measured a substantial (~50uT) field. So now I am thinking that my sensor core location is acceptable and something else caused the heading issues I experienced.

I am currently working through some battery/alternator issues. Could a weak battery or alternator, where the auto-pilot control head is powered by those batteries, cause the heading issue I experienced?

For background, my seatalk backbone (and hence autopilot control head) get power from my port batteries which are the starting batteries. I don't know why the installer set it up this way but I would like to switch that power source to the house batteries. Anyhow, I recently replaced that port alternator and suspect the cranking batteries are nearing the end of their service life as well.

The rest of my marine electronics (ACU200, Pump, Axiom, Radar, VHF) all get their power from the house batteries).

As a test, I was thinking of disconnecting the power line from the starting batteries to the SeatalkNG backbone and instead powering the SeatalkNG backbone (and thus the auto-pilot control head) via the ACU-200 so all of the electronics in my system would be getting powered off of the house batteries.

Any other suggestions?

Thanks

Dave

[Chuck - Raymarine - Moderator]

Dave,

I too would recommend that all the marine electronics be powered by the house batteries. After performing the change, it would be recommended that a Pilot Factory Reset, Dockside Wizard, and cruise to detect magnetics be undertaken again per my earlier response. All equipment (air conditioning, inverter, etc.) should be kept on during the cruise to detect magnetics to ensure that they are accounted for when determining the maximum detected deviation. Should the maximum detected deviation exceed 9 degrees, then another location for the EV-1 CCU should be chosen.

[ddfour1]

OK--I switched the power source for the STNG network (and thus AP control head) over to the house side. Reset the AP. Performed the dockside wizard which went fine and then did two cruises including a multiple figure 8's between 3 and 10 kts. The Detecting Magnetics indicator is still showing and has not advance much at all.


The auto-pilot was previously working at its current installation location without showing the Detecting Magnetics indicator so unclear why that is a problem now.

Software on my Axiom is 3.4.66. Software on the p70Rs control head is 3.07.

Thanks,

Dave

[Chuck - Raymarine - Moderator]

Dave,

Please verify that you performed a Pilot Factory Reset (see the command sequence within the previously referenced FAQ) rather than a Factory Reset of the autopilot control head. If not, then please do so and then re-perform the cruise to detect magnetic deviation. Should the problem persist, then it would be recommended that the EV-1 CCU be sent to Raymarine’s Product Repair Center to be bench checked / serviced.

[ddfour1]

I suspect I performed the Factory Reset of the control head. I will confirm when I am at the boat tonight and if that indeed is the case I will run the Pilot Factory Reset, re-calibrate, do the deviation cruise and report back.

Thanks, appreciate it.

Dave

[Chuck - Raymarine - Moderator]

You're welcome.

[ddfour1]

Chuck,

Can you please confirm that after I run the Pilot Factory Reset and re-do the dockside wizard, but before I go for the cruise to re-build the deviation tables that it is normal for the AP control head to not indicate any deviation value? It just says "---".

Thanks--just want to make sure that is not reflective of an issue before I do the sea cruise again.

Dave

[Chuck - Raymarine - Moderator]

Dave,

Q. Can you please confirm that after I run the Pilot Factory Reset and re-do the dockside wizard, but before I go for the cruise to re-build the deviation tables that it is normal for the AP control head to not indicate any deviation value? It just says "---".
A. Until the autopilot has completed detecting magnetics via the cruise, the reported deviation value will be ---. This may also be indicative of not having initially performed a Pilot Factory Reset earlier.