Fluxgate Compass/Airmar H2183

[Donzii150]

E80 classic, X10, St70, Digital Radar, DSM 300.

I've had issues with my autopilot breaking lock no matter where I position my fluxgate compass and or aligning my compass several times with around 5 degrees of deviation. I am not confident in my system although it does work OK sometimes but I have to keep an eye on it. Also, I have ohm'd out my compass and it checks out with procedures posted on forum. I have done all required updates as well. My question: Does the Raymarine fluxgate compass cycle at 1Hertz and would it be beneficial to replace it with an Airmar H2183 heading sensor at 10Hertz? I'm wondering if it gets saturated with all the equipment that I'm running and thus causing autopilot to malfunction. Thx in advance. Todd

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Donzii150,

Unlike the H2183, the fluxgate compass does not pass compensated heading data to the autopilot. The fluxgate compass provides analog heading signal in real time (>= 10Hz) to the autopilot. Accordingly, for maximum autopilot performance, Raymarine recommends that the autopilot be interfaced to the supplied fluxgate compass. The SPX autopilots may alternatively be interfaced to a source of 10Hz NMEA 0183 heading data. However, any required calibration or alignment of the 10Hz NMEA 0183 heading data source cannot be performed via the autopilot's control head. Such calibration and alignment must instead be performed via procedures specified by NMEA 0183 heading device's manufacturer.

[Donzii150]

Thanks Chuck,
So I understand that the Airmar won't necessarily give the autopilot better performance or keep it from breaking lock. True?

[Chuck - Raymarine - Moderator]

Donzii150,

It is unclear what you have been referring to using the term "breaking lock". Please elaborate.

[Donzii150]

Sorry, bad terminology.
What happens when I engage the AP, at any time it will steer itself off course, I can't seem to narrow down the cause, it is so random when it happens. It mostly turns left, not always but maybe 50% of the time. thx again. Todd

[Chuck - Raymarine - Moderator]

Donzii150,

The reported symptom may not only result from a faulty fluxgate compass, but also from a faulty rudder reference transducer or a failure within the gyro of the course computer itself. Should testing of the fluxgate compass and testing of the rudder reference transducer not identify any fault with these two components and should the problem persist, then it would be recommended that the autopilot course computer be sent to Raymarine’s Product Repair Center to be bench checked / serviced.

[Donzii150]

I do not have a rudder reference transducer on my installation. Could installing one help?

[Chuck - Raymarine - Moderator]

Donzii150,

As the design of the SPX autopilots required that the autopilot course computer be interfaced to a compatible rudder reference transducer. Autopilot performance would indeed be adversely affected through failure to have installed a rudder reference transducer. Accordingly, it is recommended that the rudder reference transducer be install, that an autopilot Factory Reset be commanded, that the Dockside Wizard and then seatrial calibration be performed. Should the problem persist thereafter and no fault be identified with the fluxgate compass or installed rudder reference transducer, then the SPX autopilot should be serviced.

[Donzii150]

Ok understood. Last question. Even though my system, Raymarine SmartPilot X-10 advertises a rudder reference-less operation, you still recommend that I install a rudder ref. transducer?

[Chuck - Raymarine - Moderator]

Donzii150,

While an argument may be made for an Evolution autopilot to be installed without a rudder reference transducer, the same may not be said for the SPX autopilots. Both the SPX and Evolution autopilots feature a virtual rudder sense when operating in Auto and Standby modes. However, the capabilities of this feature are limited, particularly when operating at slower speeds. It should be noted that a rudder reference transducer is included within the package of Evolution ACUs. Should performance following installation a SPX autopilot or Evolution autopilot not be satisfactory, then the first action typically recommended would be the installation of a rudder reference transducer. While there may have been some claims to the contrary when the SPX autopilots first hit the streets, the experience gained thereafter had reversed any such position. Accordingly, my prior recommendations stand in that a rudder reference transducer should be installed along with a SPX autopilot.