[CA] [CA11] ST6001 Calibration Issues

[tpburt]

Just recently purchased a used 26' Cat fully equipped with Raymarine electronics. I'm new to Raymarine and also never worked with an Autopilot so the learning curve is steep. Problem I have is the compass is roughly 100 degrees off on the AP so I went out last weekend to try and calibrate. The control unit is a ST6001 and I followed the directions to initiate the SeaTrial calibration. Once the prompt pops up to start your turns I turned as slow and as wide as I could trying to complete a turn in a little more than 2 min. I never could get the "Turn Boat" prompt to go away, not even by increasing speed to tell me if was turning too fast. Sorry, I know this is probably a simple fix but got dizzy after about an hour of donuts and gave up. Any suggestions would be appreciated. Thanks.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum tpburt,

The reported issue may be indicative of a problem with the autopilot's fluxgate compass or with the autopilot course computer itself. It is recommended that the autopilot's fluxgate compass be tested. Instructions for testing the autopilot's fluxgate compass may be found here. Should the fluxgate compass pass testing, then please respond with the model of autopilot course computer which is installed onboard.

[tpburt]

Thank you for your response Chuck. I got the following results from the resistance test:
R-G --- 5.5
R-Y --- 5.3
G-Y --- 8.4
Screen to Blue --- 8.4
Updated readings with an different meter...

[Chuck - Raymarine - Moderator]

tpburt,

A failure would be identified should any of the above listed resistances show an open circuit (infinite resistance) or deviate from the above listed resistance value by +/-
2 Ohms ... your fluxgate compass would appear to be operational as long as it did not fail the portion of the test which would test for binding. Failing fluxgate compasses should be replaced with a M81190 Fluxgate Compass which may be ordered from an authorized Raymarine dealer. Should this testing not indicate a failure with the fluxgate compass, then the autopilot course computer would be deemed to have suffered a failure, necessitating that it be serviced or replace (the latter would be required for autopilot course computer designs introduced prior to Raymarine's SPX autopilot course computer).

[tpburt]

After doing a third check on the compass, I'm comfortable that is not my problem. The course computer model is a Smart Pilot 4538-001. I don't know where that falls in the lineage of autopilot computers.

[Chuck - Raymarine - Moderator]

tpburt,

The SmartPilots were a family of autopilot course computers capable of gryo-stabilizing heading data. These autopilots included the S1G, S2G, S3G, Type 150G, and Type 400G. Raymarine also off these autopilot course computers in non-gyrostabilized versions. The symptom which you have reported is commonly associated with failure of the autopilot course computer's gyro. Unfortunately, parts and service are no longer available for any members of this family of autopilot course computers.

That said, it often possible to gain some additional life from the SmartPilot autopilot course computer having a gyro failure. This is accomplished by simply unplugging the gyro's cable from its socket on the course computer's processor board. Doing so would then cause the SmartPilot autopilot course computer to function like the corresponding non-gyrostabilized variant (i.e. S1, S2, S3, Type 150, Type 400). Photos of the gyros employed within SmartPilots may be seen below.

[tpburt]

I'll double check but believe it is the older one you've shown. So if I disconnect, just follow the calibration procedure for the non-gyro units?

Is it possible to just replace the course computer, and if so, what model would I need to go to?

[Chuck - Raymarine - Moderator]

tpburt,

Q1. So if I disconnect, just follow the calibration procedure for the non-gyro units?
A1. Yes.

A2. Is it possible to just replace the course computer, and if so, what model would I need to go to?
A2. Unfortunately, it is not possible to do as you have suggested. Raymarine's currently manufactured autopilot is not compatible with the ST6xxx/ST7xxx/ST8xxx and ST70 Autopilot Control Heads. However, it the currently installed drive unit and rudder reference transducer are compatible with the Evolution Autopilots (to include a p70S/p70RS Autopilot Control Head, EV-1 CCU (performs course computer and heading sensor), and ACU-[censored] (model based upon the model of drive unit which is presently installed onboard the vessel).

[tpburt]

Took some time over the Thanksgiving week and did some additional troubleshooting.

When I try to complete the Seatrial calibration, the control unit will not change from "Turn Boat". As suggested, I also tried running through the calibration with the gyro disconnected but ended with the same result. Even if I speed up and run in circles or a straight line it will not change from Turn Boat.

If I select any waypoint and engage the autopilot, it will begin to work, just heading in the wrong direction. Does the fact that the AP engages rule out a problem with the computer?

[Chuck - Raymarine - Moderator]

Trent,

Q1. When I try to complete the Seatrial calibration, the control unit will not change from "Turn Boat". As suggested, I also tried running through the calibration with the gyro disconnected but ended with the same result. Even if I speed up and run in circles or a straight line it will not change from Turn Boat.
A1. When turning the boat to determine the deviation field sensed by the fluxgate compass, the rate of turn must be very slow. Should the rate of turn be too fast and there be no issue with the fluxgate compass or course computer, then the operator will be informed that the vessel's rate of turn is too fast. The fluxgate compass test is used to determine the operational state of the fluxgate compass.

Q2. Does the fact that the AP engages rule out a problem with the computer?
A2. No.