Heading Sensor - Error in one direction
- Thread starter ralph162
- Start date
Mounting location is bad most likely. Some big metal, magnet, or electrical is pulling at the compass. When the problem happens going west, then the item is probably between the compass the direct of north as the boat is moving west. Flux gates are for non-metal boats and should be mounted in a location away from any items that can cause problems. The base should be mounted flat not upside down etc.
Strange...I went through the whole "magnetic field" detection process last year. Turned out there was a magnetic door catch on the opposite side of the bulkhead where the pg-700 was mounted. Once that was moved, the compass was fine. There is a house battery 18" from the compass, but that did not seem to interfere with the compass. I had even verified with a handheld compass. Used it all last year without an issue. All of a sudden this year there is an issue.
The only thing different this year is I ran an always energized 10g power wired from that house battery to a Fusion radio. This wire parallels the PG-700 NMEA drop Cable to the backbone. Do you think this could have an effect? I will de-energize it this weekend and see.
The only thing different this year is I ran an always energized 10g power wired from that house battery to a Fusion radio. This wire parallels the PG-700 NMEA drop Cable to the backbone. Do you think this could have an effect? I will de-energize it this weekend and see.
Sure EMI fields from nearby power cables can pull a compass. Something about the dynamics changed by the sound of it. I have seen people put motor powered fishing reels near the compass, steel toed boots, paint cans, you name it.
Checked for EMI yesterday. First, as a precaution, I de-energized the radio power wire that runs parallel to the PG-700's NMEA drop cable. Then, using a hand compass, I checked for any EMI around the PF-700 . The area where it is mounted appears completely devoid of any EMI. The nearest source would be a house battery about 18" away. But I don't pick up any EMI from the battery unless I get within an inch of the positive post. Which does not surprise me, as it never created an issue before wit the PG-700.
Any suggestions? Could it be a setting in 711C? Could it be a defective PG-700? Recalibrate? Not sure what else to check now. I may try moving the heading sensor temporarily and running a temporary NMEA drop cable away from anything. But I am doubtful that will make a difference.
For now, I notice the heading sensor is off by about 10 deg in one direction. I used the 711C to make an adjustment of -5 deg to split the difference. So for now, the worst I will be is off by 5 deg in any direction. Not a very good solution, but all I have for the time being.
Any suggestions? Could it be a setting in 711C? Could it be a defective PG-700? Recalibrate? Not sure what else to check now. I may try moving the heading sensor temporarily and running a temporary NMEA drop cable away from anything. But I am doubtful that will make a difference.
For now, I notice the heading sensor is off by about 10 deg in one direction. I used the 711C to make an adjustment of -5 deg to split the difference. So for now, the worst I will be is off by 5 deg in any direction. Not a very good solution, but all I have for the time being.
I don't think I have ever seen a PG700 go back except if water gets inside it. They normally work or they don't. If you doubt it, it can always be sent in for testing. Any problems normally relate to placement and calibration on the boat. You might have to get your dealer involved.
Sounds good. I will de-energize the power cable running parallel to the PG-700 NMEA cable, then try a reset/re calibration. If that doesn't help I will move and test the PG-700. If that still doesn't help, I will have the dealer send a tech...but that takes a looooong while!
I had it working fine last year after I moved the magnetic door catch. This year I updated the firmware and ran a radio power wire alongside the NMEA cable. That's it. Now I can't get it to maintain a consistent offset. But I will try what I mentioned above.
I had it working fine last year after I moved the magnetic door catch. This year I updated the firmware and ran a radio power wire alongside the NMEA cable. That's it. Now I can't get it to maintain a consistent offset. But I will try what I mentioned above.
Still no luck. Checked for any magnetic interference using a handheld compass. Nothing. Did a unit self-check. Passed. I did a unit reset on the PG-700 and ran a calibration. Here is where I end up..
N 0 = 5 (+5)
E 90 = 87 (-3)
S 180 = 175 (-5)
W 270 - 277 (+7)
I added 1 deg East offset. That brings all error too +/- 4-6 deg. Not perfect, but the best I can get.
N 0 = 5 (+5)
E 90 = 87 (-3)
S 180 = 175 (-5)
W 270 - 277 (+7)
I added 1 deg East offset. That brings all error too +/- 4-6 deg. Not perfect, but the best I can get.
Flux gate placement can be tricky. Much like transducer placement. They key to good information is getting the right location.
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