AUTOPILOT TECHNICAL FORUM-  NOTES

The following technical notes contain updates for various autopilot systems and helpful diagnostic tips not contained in all manuals.

ALL SYSTEMS - OPTIMIZING PERFORMANCE

TUNING FOR MAXIMUM PERFORMANCE

Compass Gain - This control can be used to optimize steering performance for your vessel. How every boat responds to the helm is different. Therefore to get the most out of your autopilot it is necessary to adjust the pilots performance to match the requirements of your vessel. The most straight forward way of doing this is as follows.

Set the yaw control to minimum.

Get the vessel to it's maximum speed. This may be under engine or it could be surfing on a wave but no matter what the circumstance the optimum system performance is always adjusted at the highest vessel speed. Under these conditions quickly alter course at least ten degrees. The vessel should come to the new heading and steady up on the new heading with just one overshoot. If the pilot overshoots more than once adjust the compass gain toward minimum. If the pilot is sluggish to respond, adjust the compass gain toward maximum.

If the pilot subsequently fails to perform properly make sure that nothing is affecting the compass sensor. If you subsequently find the vessel is in a condition where the speed is greater than when the control was set, repeat the procedure. 

If you have made a large latitude or longitude change you may have to repeat the procedure for optimum performance.   For more information on how the earths field changes as a function of location please visit a web page such as  http://www.ngdc.noaa.gov/geomag/WMM/icons/WMM2010_H.png

ADJUSTING AUTOPILOT PERFORMANCE - RELATIVE TO WIND DIRECTION

What follows is a compellation of thoughts from a number of Alpha pilot users.

There are two controls on Alpha pilots which can be used to advantage to optimize performance and reduce power consumption.

The yaw control allows you to select how "tight" a course the pilot is to hold.

If you are going to weather wave action causes the bow to swing, but long term, if you hold the wheel steady, the action will average out and little helm action is required. This can be achieved, when the pilot is steering, by turning the YAW control, counter clockwise, toward maximum. To improve long term course accuracy AUTO TRIM can be turned on and an additional control loop will be activated. This loop looks at all the short term course deviations and finds their average and corrects the pilots heading. This loop also tracks the changes in weather helm and corrects those as well.

Usually when sailing down wind, especially when the wind is almost directly astern, you want the pilot to be as responsive to heading changes as possible. So, you tell the pilot to allow "MINIMUM" YAW. This is effected by turning the YAW control clockwise toward MINIMUM YAW. It is suggested that AUTO TRIM be turned off under these conditions.

 

DRIVE LINK  LATCH ENGAGEMENT 3000 systems 

If you are having difficulty engaging the pilot you might try the following procedure.

1. Adjust the "tension lock" the knurled nut below the T handle tight enough so that the handle will stay out " latch engaged" tight enough that when you rotate the helm it does not pull the handle in, but not so tight that you can not push to disengage.

2. Sail the boat on the heading you wish to hold.

3. Set the course setting knob to a heading below the course you wish to hold and turn on the pilot.

3. Pull out the Morse handle to engage.

4. slowly rotate the course knob until the latch locks the pilot to the steering.

5. fine tune the heading using the helm knob.

6. If the Auto-trim (TM) system is on, you may have to readjust the course knob as the pilot "learns" how much lea or weather helm is required to trim out the vessel.

DRIVE LINK  LATCH ENGAGEMENT Spectra and 4000  systems 

If you are having difficulty engaging the pilot you might try the following procedure.

1. Adjust the "tension lock" the knurled nut below the T handle tight enough so that the handle will stay out " latch engaged" tight enough that when you rotate the helm it does not pull the handle in, but not so tight that you can not push to disengage.

2. Sail the boat on the heading you wish to hold.

3. Turn on the pilot and select the helm mode.

3. Pull out the Morse handle to engage.

4. Slowly rotate the helm knob until the latch locks the pilot to the steering system.

5. Fine tune the heading you want to hold using the helm knob.

6. Press course set when on course and select pilot mode.

7. If the Auto-trim (TM) system is on, it may take a minute or two for the pilot "to learn" how much lea or weather helm is required to trim out the vessel. It will then tack any weather helm changes which occur. 

 

DIAGNOSTIC TOOLS FOR ALPHA 3000 & 4404 Autopilot Systems

A useful diagnostic tool for systems where the drive unit is unresponsive or responding incorrectly is to;

1. Remove all five wires that connect the drive at the rear of the control unit.

2. Turn on the pilot.

3. Connect a volt meter between pins 6 and 7.

4a. Swing the course setting knob ( on 3000 systems) port or starboard of the present ships heading and observe the voltage

On the volt meter. It should be approximately equal to the supply voltage when significantly off course and should drop to zero as the knob is rotated through the present heading and then rise to supply voltage but of opposite polarity when the knob is again significantly off course to the other tack.

If  a remote helm is part of the system it should be disconnected at the rear of the control unit prior to this test.

4b. On 4404 systems select helm mode and swing the helm knob port or starboard of the center helm position and observe the voltage on the volt meter. It should be approximately equal to the supply voltage. As the knob is rotated through the center helm position the voltage should drop to zero and then rise to supply voltage but of opposite polarity when the knob is again significantly off the center helm position but on the other tack.

DIAGNOSTIC TOOLS FOR ALPHA  FOR SPECTRA  SYSTEMS

Systems which fail to turn on may not have suffered a failure. In the Spectra CPU the boards are inter connected via a 26 pin connector. This connector, located on the board edge opposite where wire connections are made can become disconnected if excessive force is put on the wiring board edge. The solution is to either press down on the 26 pin connector or remove the boards and reinstall them.

On systems utilizing the C I/O computer interface card, it is recommended that this be removed if it is not connected to the external control switches and computer as this can, under some circumstances, cause a degradation in performance.

A useful diagnostic tool for systems where the drive unit is unresponsive or responding incorrectly is to;

With all system components connected :

1. Remove all five wires that connect the drive to the control unit.

2. Turn on the pilot.

3. Connect a volt meter between the two pins where the drive unit power leads connect.

4. Put the pilot in Helm mode and swing the Helm knob to port or starboard. and observe the voltage

On the volt meter. It should read approximately equal to the supply voltage when significantly off center and should drop to zero as the knob is rotated through the center helm position and then rise to supply voltage but of opposite polarity when the knob is again significantly off center on the other tack.

 

LINEAR DRIVE TESTS

To test the rudder feedback portion of the drive
 
  Using a volt /ohm meter make the following measurements with the feedback wires disconnected from the control unit. 
......a. Check 10K ohms red to white
..........Check 5K ohms green to red
..........Check 5K ohms green to white
..........All above readings with the drive unit at it's center helm position
..........
 
To test the motor you can use an ohm meter and read a resistance of less than 2ohms or if you are cautious you can briefly touch the motor leads to 12volts. ( be very careful not to drive to its mechanical limits as it can cause damage.) 

Service Hint: The only part of the linear drive which needs, or should be lubricated is the ball joint where it connects to the drive link. The 1" stainless shaft should not have anything put on it as the black bushing at the end is self lubricating Delrin ( R) and the proper maintenance is to keep the 1" shaft clean and dry.

If you are experiencing problems with the drive unit over extending / retracting or any other un explained instability please check that there are no cable splices in the drive unit wiring that use anything but soldered joints as these circuits must have the greatest integrity to work properly. 

LIGHTNING AND THE EMP EFFECT

Please visit our page in which we offer information on lightning and the related EMP ( electro magnetic pulse) . We hope you will find this valuable in learning more about these natural phenomenon and what you can do to protect your vessel LINK

 

CAUTION NOTES:

Shipping to Alpha Marine Systems- please see our shipping instructions page

COMPASS SENSORS 

Our sensors have a long history of unparalleled performance and long life.

The longevity of your compass sensors will be enhanced if the following precautions are observed .

Don't leave the sensor in the hot sun for any extended period or mount it in a hot location such as an engine room or space. The fluid inside will expand putting extreme pressure on the seal and cause the seal to break.

Don't attempt to rotate the compass housing, especially when mounted in it's bracket. 

Either of these puts excessive strain on the seal and can break it which in turn can result in a loss of damping fluid or the damping fluid cup becoming detached. 

AGM Batteries 

One of the newer power storage developments are AGM batteries. We bring this up in TECH TALK because these batteries can be charged at higher voltages than previous battery technologies allowed. Traditionally lead acid batteries were charged at a voltage of 13.8 - 14.2 volts. AGM batteries will also charge at 13.8 but can be charged at voltages as high as 15.6 volts. 

We bring this to our pilot owners attention because the higher voltages can cause a shortening of the life of your drive motor in systems not incorporating the Dash 9d6 technology . Higher voltage will also increase the heat dissipated in all of our control systems. If you are operating your pilot in warm to hot climate or if your control unit is in an enclosed locker you should be aware of the potential for a system failure when operated at these elevated voltages. 

Your AGM charging system should allow for the selection of a maximum charging voltage of 14.2volts which is advised when using any of our pilots.

DATED May 2015