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Rudder goes hard over when autopilot commanded into Auto or Track mode
09-02-16, 09:47 AM (This post was last modified: 01-10-17 12:13 PM by Chuck - Raymarine - Moderator.)
Post: #1
Rudder goes hard over when autopilot commanded into Auto or Track mode
Rudder goes hard over when autopilot commanded into Auto or Track mode

The subject problem is typically caused by incorrect drive motor phasing or and incorrect rudder reference transducer phasing. Both of these items are typically verified/corrected as a result of executing the Dockside Wizard (Evolution autopilots) or Dockside Calibration procedure (older autopilots). Correction of motor phasing or rudder reference transducer phasing may be accomplished via the autopilot control head (Evolution autopilots) and/or changing the ACU or autopilot course computer motor and/or rudder terminals to which the drive motor and/or rudder reference transducer lead have been connected.

Should the vessel be fitted with a rudder reference transducer, then it should be tested prior to testing for motor phasing. While rudder references transducers are optional for the Evolution autopilot, they are necessary for the generations of autopilots which preceded the Evolution autopilots. Maximum autopilot performance will generally be achieved when an rudder reference transducer has been interfaced to the autopilot. Should an Evolution autopilot not be fitted with a rudder reference transducer, then it will perform as if it has a virtual rudder reference transducer when the vessel is underway and making good way. Accordingly, the Evolution autopilots which have not been interfaced to a rudder reference transducer will be unable to detect/indicate rudder movement when the vessel is stationary (i.e. dockside, anchored, moored, becalmed, etc.).

NOTE: the following test should be executed while the vessel is dockside, anchored, or moored.

During execution of the Dockside Wizard or Dockside Calibration should movement of the wheel in a clockwise direction or movement of the rudder to the right cause the rudder bar displayed on the autopilot control head to indicate left rudder was applied, then the rudder reference transducer phasing is incorrect for the orientation of the rudder reference transducer. In the case of Evolution autopilots, the command sequence MENU->SET-UP->AUTOPILOT CALIBRATION->DRIVE SETTINGS->REVERSE RUDDER REF may be executed to correct this behavior. Alternatively,
- the rudder reference transducer's red lead may disconnected from ACU/course computer RUDDER port's red terminal and may instead be connected to the ACU/course computer RUDDER port's green terminal; and
- the rudder reference transducer's green lead may disconnected from ACU/course computer RUDDER port's green terminal and may instead be connected to the ACU/course computer RUDDER port's red terminal.

NOTE: the following test should be executed while the vessel is dockside, anchored, or moored. When performing phase testing of the drive motor, the autopilot should be commanded from AUTO to STANDBY as soon as the direction motion wheel or rudder/drive resulting from the +10 command has been determined.

Failure to correctly phase the drive motor will result in the rudder/drive being moved in the direction opposite that which has been commanded. Accordingly, should the autopilot be commanded into AUTO mode and +10 degrees of heading change be commanded, then the wheel and rudder/drive should move clockwise and to the right respectively. Should the wheel and rudder/drive instead move left respectively, then the drive motor phasing is incorrect. In the case of Evolution autopilots, the command sequence MENU->SET-UP->AUTOPILOT CALIBRATION->DRIVE SETTINGS->MOTOR PHASING may be executed to correct this behavior. Alternatively,
- the drive motors A lead may disconnected from ACU/course computer MOTOR port's A terminal and may instead be connected to the ACU/course computer MOTOR port's B terminal; and
- the drive motors B lead may disconnected from ACU/course computer MOTOR port's B terminal and may instead be connected to the ACU/course computer MOTOR port's A terminal.

NOTE: Executing a Pilot Factory Reset (ex. MENU->SET-UP->AUTOPILOT CALIBRATION->COMMISSIONING->PILOT FACTORY RESET) command will cause accordingly reset the MOTOR PHASING and RUDDER REFERENCE phasing settings to be restored to the default settings. Should changes be made via the autopilot's control head to the MOTOR PHASING and/or RUDDER REFERENCE phasing settings, then these settings will be deleted when the Pilot Factory Reset is commanded, necessitating that these settings be reconfigured per the command sequences specified above.

RAYFAQ#
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