NavPilot 511 and RRU FAP-6112 Erratic Behavior


New member
I am having an issue with my Furuno NavPilot 511 and the Rudder Reference Unit FAP-6112. When turning either to port or starboard, the rudder degree turn display jumps from say 3 degrees to 18 or another random number. This happens randomly as the wheel is turning, and it makes the autopilot jig all over the place, overcorrecting. It will sometimes just settle down and work correctly and then it will jump around.

This happens whether the autopilot is engaged or not engaged and I am hand steering. I’ve checked the RRU, made sure it was secure, and everything seems to be connected correctly. Any suggestions? Worst part is it appears to be intermittent.
It does sound like you might have a bad feedback unit. A local dealer should be able to test it for you.
What version of software are you using? The controller should be "xxxxxxx-03.01" and the processor should be either "xxxxxxx-03.08" or "xxxxxxx-04.08" depending on what processor you have. Also, check the RRU resistance while turning the arm fully from one side to the other; the resistance should smoothly change from approximately 0 Ohms on one side to approximately 2200 Ohms on the other side. If the resistance jumps as you are turning the arm, then there is a bad spot in the RRU and it'll need to be replaced. Lastly, try re-running the rudder limit setup under the dockside setup menu; don't forget to physically turn the helm in the direction you are setting and pressing the enter knob to change the value and enter to set OR press the enter knob twice to re-store that value as the position of the rudder. What you are doing is telling the processor that when it detects the Ohm value sent from the RRU, the rudder is fully deflected in the direction you are setting. Hopefully this makes sense.
I have exactly the same problem: erratic change of rudder angle on the display. How did you eventually solve the problem? Did you have to exchange the Reference Unit?
Thank's for your help!
The first thing to check is the physical mounting of the rudder feedback. Make sure it is securely mounted and the lever arm is tight. Things could have loosened over time.
If everything back there checks out OK then check the smoothness of the feedback from the control head by manually turning the wheel.
With the pilot in standby bring the wheel hard-over to port or starboard to the stops. Then slowly and steadily turn the wheel the other way while watching the rudder angle display. It should run smoothly and not hang up on a number and jump forward or back.
If it does then you most likely need a new one or you have air in your steering system. Bleed the system before going to the expense of a new feedback.
One other thing that can cause that issue is if your control indicator bus is not terminated. If you call into tech support they can help talk you through any troubleshooting.