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Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
06-10-17, 02:04 PM
Post: #1
Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
Hello,

Most of the time, my heading and COG is accurate, however on occasion the heading will be off by 90 degrees or more on all instruments. I began to experience this problem with my old S3 and Fluxgate. I first replaced the Fluxgate and had the same issue. I then removed the S3/Fluxgate/NG converter (now all NG network with exception of NMEA AIS) and replaced with an ACU400 and EV-1, the problem still exists.

Photos attached show the problem. These were approx 5 mins apart with the autopilot set to a fix heading (note autopilot did not turn the boat when heading changed so it seems the correct somewhere but displays incorrectly).

Not sure what to do next, any thoughts?
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06-12-17, 01:46 PM
Post: #2
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
Welcome to the Raymarine Forum

Unfortunately, your photos were not received. Which device within your system is acting as the system's GPS data source? Has this device been installed in a location affording it an unobstructed view of the skies overhead? Was the vessel underway when the reported problem was observed? If so, what was the approximate SOG of the vessel?

Please click here to view a FAQ addressing items which may affect the heading reported by the system. What was the maximum deviation detected by the Evolution autopilot since calibration (MENU->SET-UP->DIAGNOSTICS-ABOUT PILOT)? When the difference between COG and heading is observed, how does the heading value compare with the vessel's properly calibrated fluid filled compass?
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06-12-17, 02:17 PM
Post: #3
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
Thanks Chuck, adding the photos for your reference.

In the photos, the COG is correct in both photos, heading seems to be the one that will get out of sync (display of heading data is incorrect and also is displayed incorrectly on E125, however, the AP steers the same course when the heading displayed changed by over 200 degrees).

As for SOG/speed, this occurs at any speed (sailboat so typically between 4-8 knts). Max deviation is 8 degrees and I have re-calibrated multiple times.

As for the fluid compass and COG/Heading, the COG is being reported accurately, heading is the one that is off. Once heading data "snaps out of its funk", the reading seems to be accurate and fairly well aligned with COG (with current, wind, etc being factored in).

I have 2 GPS sources, RS130 and E125. RS130 has great visibility with no obstructions to the sky. I have the data source set to "Auto" which seems to prefer the RS130. I have also manually switched to the E125 GPS and seen the same anomaly in the heading.

What I find strange is that I had the same behavior with the old S3/Fluxgate and the new ACU400/EV1. Seems the heading message is being corrupted somehow on the SeaTalk network.

anyway to capture diagnostics data while the error is occurring that may help? Any additional thoughts?
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06-12-17, 03:57 PM (This post was last modified: 06-12-17 03:59 PM by Chuck - Raymarine - Moderator.)
Post: #4
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
lwitty,

What was the maximum deviation detected by the Evolution autopilot? When was the autopilot installed? What version of software is presently installed within each of the autopilot components (MENU->SET-UP->DIAGNOSTICS-ABOUT PILOT)? Regarding the possibility that the problem may be resulting from integration with another device, please attach a system diagram (a photo of hand drawn diagram will suffice) identifying each device (including computers) and how each as been interfaced to the system.
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06-12-17, 05:01 PM
Post: #5
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
At the boat now, here is the requested data:
- Max deviation 8 degrees
- Autopilot installed around May 1, 2017 (one reason for the upgrade is this problem existed with the old S3/Fluxgate - though new AP would solve issue). Update of all software was completed from the E125 (connected via WiFi) during initial install.

- AP components
- ACU400 - V2.23 (RSCP v1 L4)
- EV-1 - V2.17 (RSCP V1 L4)
- 2 P70s V3.07
Other RM Components
- E125 V19.03-00036
- 4kW 18" HD Color Radome (SeaTalkHS) v4.27
- 2 i70s V3.08
- RS130 GPS V2.20
- iTC5 V1.12 (wind, speed/temp & depth transducers attached)

Non-RM Components
- AMEC Camino 101 Class B AIS (connection to receive GPS from NMEA 0183 and send AIS data to E125)

Above are all the components connected (no computers other components).

Diagram is attached with the actual wiring.

I have also attached the diagnostics file for all devices (xml & html). I also have the log files which I can attached to another post if needed.
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06-13-17, 10:40 AM (This post was last modified: 06-13-17 10:41 AM by Chuck - Raymarine - Moderator.)
Post: #6
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
Thanks for supplying the requested information,

Your diagram appears to show a properly networked system. With respect to maximum deviation detected, it should be noted that upon completion of detecting magnetic deviation the autopilot's control head will report the maximum deviation detected. However, this number will be refined over time and will be reflected within the deviation specified with the About Pilot information (command provided within the prior response). Should this indeed be the source the deviation value which you have reported, then the EV-1 Sensor Core's installation location would be deemed satisfactory.

It is recommended that you verify that the ACU-400's SeaTalkng Power Switch has been configured to OFF position. Failure to do so may result in a ground loop, potentially causing unpredictatable system performance.

It is recommended that you verify that the EV-1 Sensor Core's arrow is oriented parallel to the keel and in the direction of the bow.

The software within the EV-1 Sensor Core and RS130 is not current. It is recommended that the software within these two components be updated with the latest available Raymarine product software updates.

Upon completion of the above, it is recommended that a Pilot Factory Reset be performed, Dockside Wizard executed, and deviation/vessel handling cruise performed again. Please click here to view a FAQ addressing this subject. Any adjustments to the heading (+/- 9 degrees) may be made via the autopilot control head. Upon completion of these actions should the problem re-occur and should the maximum sensed deviation not exceed 10 degrees, then it would be recommended that the EV-1 Sensor Core be sent to Raymarine’s Product Repair Center to be bench checked / serviced.
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06-13-17, 11:29 AM
Post: #7
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
Thanks Chuck, I will perform the recommended actions this afternoon.

Two more questions since I have fwd'd the network diagram to you:
1) is the LEN setup correct? Given the power comes into the 5-way, not sure if that is really the "middle" of the network or not.
2) Depth has been acting up and really noticed it since the install of the ACU400 (not sure if related or not...). I will verify that the SeaTalk power is off on the ACU400 but I have also read that removing the shield from the depth transducer to reduce noise has been recommended. If SeaTalk ACU power is off, is good next step to remove the shield (transducers where installed with the old ST instruments and individual depth and speed/temp - not a DST800).
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06-13-17, 12:24 PM
Post: #8
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
lwitty,

Q1. Is the LEN setup correct? Given the power comes into the 5-way, not sure if that is really the "middle" of the network or not.
A1. I did indeed inspect LEN balancing within your STng network and it appears to be satisfactory.

Q2. Depth has been acting up and really noticed it since the install of the ACU400 (not sure if related or not...). I will verify that the SeaTalk power is off on the ACU400 but I have also read that removing the shield from the depth transducer to reduce noise has been recommended. If SeaTalk ACU power is off, is good next step to remove the shield (transducers where installed with the old ST instruments and individual depth and speed/temp - not a DST800).
A2. I don't suspect that the problem is rooted in the how the DST800 has been wired to the iTC-5. Should the problem not manifest itself when the vessel is stationary, operating under power alone (i.e. sails not set to expose the vessel to heeling forces) in depths up to approximately 150', then the reason for the symptom reported may simply be a limitation of the DST800's design. Unlike full size through hull instrument depth transducers, the DST800's element is half that of Depth-only or Depth/Temp transducer designed to fit within the same housing. While a good option for powerboats seeking a single transducer to support supplying the system with depth, speed, and temperature, it may more easily loose bottom contact on a heeling sailboat. Should the problem not be produced when stationary or under power only, then it would be recommended that and additional depth-only transducer (ex. E26030 D800/P17, etc.) be installed to replace supplying depth signal to the iTC-5.
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06-13-17, 08:56 PM
Post: #9
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
Okay, I performed the following today:
1) Upgraded EV-1 software successfully
2) Upgraded the RS130 software successfully
3) Verified the ACU-400 SeaTalk power switch is off
4) Verified EV-1 arrow is pointing towards the bow. EV-1 is installed on the centerline of the boat behind the keel and at least 3 feet from any metal objects, compasses and radios.
5) Reset the pilot to factory settings then performed dockside wizard.

I then performed a sea trial with the following actions/results:
1) Completed multiple turns to allow compass calibration to complete. Completed with a variation of 10 degrees.
2) Verified the AP was holding course in Auto and Wind Vane mode - operated as expected.
3) All seemed fine for the first hour, however when heading back to the dock with the AP engaged on a fixed heading, the MDF seemed to go askew again - please see the attached photos. Here are the anomalies represented in the 2 photos taken within seconds of each other:
a) The chart is configured to be in Headsup mode with a 2/3 offset, so given the boat was going 7.7 knots on a fixed heading, the boat symbol should have been in the lower 1/3 of the screen.
b) You can see the COG is 148 degrees true and the Heading is 137 degrees true. However, the chart is showing the heading vector (purple) pointing at an estimated 360 degrees while the COG vector is showing the correct 148 degrees.
c) Note the correct heading is being displayed on the I70, but not the chart on the E125 vector and boat symbol positioning.

Given the above description, plus the fact I was seeing these exact symptoms before I upgraded the S3/Fluxgate to the ACU/EV-1(which is one of the reasons why I decided to replace the fluxgate and then replace the old S3 & fluxgate with the ACU-400/EV-1), it seems the heading information is correct and not an issue with the EV-1.

Next trip out, I will configure the MDF to show both Heading and COG data to determine if the heading matches the Heading Vector.

Any other thoughts on the heading issue?

The second issue, depth, seemed to be much more stable this time out. Seemed very accurate while out motoring and sailing and I only saw it drop to 0 feet once while in 200 feet of water. Since the depth started acting up, I would see this behavior multiple times in one hour. However, when I returned to the dock, I noticed it was reading 0 feet again then jumped back to 5-6 feet and back to 0 feet several times within a few minutes.
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06-14-17, 09:12 AM
Post: #10
RE: Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)
lwitty,

The heading behavior is very odd indeed. I would recommend the following:
1) Should the autopilot's heading be within 9.9 degrees of the actual heading, then it is recommended that the autopilot's heading be adjusted (MENU->SET-UP->AUTOPILOT CALIBRATION->COMMISSIONING->ALIGN COMPASS) via the autopilot control head to match the actual heading.
2) Rule out the possibility of any data looping from NMEA 0183 sources. Temporary cessation of communications between the MFD and NMEA 0183 devices may be achieved by simply configuring the MFD's NMEA 0183 communications port(s) BAUD rate to not match that of the interfaced NMEA 0183 device(s). For example, should the MFD be interfaced to an NMEA 0183 AIS receiver/transceiver, then temporarily change the BAUD rate of the MFD's port from 38400 to 4800 (AIS data communications is performed via NMEA 0183 High Speed (i.e. 38400 BAUD)).
3) Switch the entire marine electronics system OFF, and then ON again.
4) Test the system
5) Should the problem persist when operated under the conditions specified in item 2), then it would be recommended that the MFD's software be reset (HOME->SET-UP->MAINTENANCE->SYSTEM SETTINGS RESET), that the system then be manually reconfigured, and that the system then be tested again under the conditions specified in item 2).

Regarding the depth issue associated with the DST800, should the problem have manifested itself with the boat being stationary and the depth of the water be at least 3' beneath the transducer, then it may indicate fault with the transducer's installation, the iTC-5, or the transducer itself. do you have any photos taken from outside of the hull showing transducer's installation location in relation to the vessel's keel?
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