Troubleshooting Raymarine autopilot – Motor phasing and rudder reference transducer

Step-by-step guide to correct incorrect phasing and optimize autopilot performance with Dockside Wizard and ACU connections.

Autopilot steering problems are often due to incorrect phasing of the drive motor or the rudder reference transducer. These are normally checked and corrected via the Dockside Wizard (Evolution autopilots) or Dockside Calibration (older models).

Correction can be made via the autopilot control head (e.g., p70s) or by changing the connections on the ACU/autopilot course computer's motor and rudder terminals.

Test the rudder reference transducer first

If the vessel has a rudder reference transducer, it should be tested before motor phasing. Although the transducer is optional for some autopilots, it provides maximum performance when connected.

NOTE: The following tests should be performed when the vessel is at the dock, anchored, or moored.

Incorrect rudder phasing – How to identify the problem

During Dockside Wizard/Calibration: If the wheel is turned clockwise but the autopilot display shows port rudder, the phasing is incorrect.

Solution via p70s: MENU → SET-UP → AUTOPILOT CALIBRATION → DRIVE SETTINGS → REVERSE RUDDER REF

Alternative (best practice):

• Connect the rudder reference transducer's red wire to the green terminal on the ACU's RUDDER port.
• Connect the rudder reference transducer's green wire to the red terminal on the ACU's RUDDER port.

Motor phasing test

If the autopilot is commanded to AUTO and a +10° course change is made, the wheel and rudder should move to the right. If they move to the left, the motor phasing is incorrect.

Solution via p70s: MENU → SET-UP → AUTOPILOT CALIBRATION → DRIVE SETTINGS → MOTOR PHASING

Alternative:

• Connect the drive motor's A-wire to the B-terminal on the ACU's MOTOR port.
• Connect the drive motor's B-wire to the A-terminal on the ACU's MOTOR port.

Important to know about factory reset

A Pilot Factory Reset (MENU → SET-UP → AUTOPILOT CALIBRATION → COMMISSIONING → PILOT FACTORY RESET) restores MOTOR PHASING and RUDDER REFERENCE to default. If you have changed these settings via the control head, you must reconfigure them or make physical cable changes again.