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Old 25-04-2019, 23:22   #46
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Re: Compass Deviation Plugin future requests.

Hi,

rgleason: Yes, Iīll have a cup of tea meanwhile ;-)

Regards

Andreas
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Old 03-06-2019, 23:02   #47
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Re: Compass Deviation Plugin future requests.

Hi,

does the plugin in the actual version sends true heading to OC?
I set an input filter in OC for the NMEA Sentences. Is it necessary to add a new sentence to that filter so that OC can get the Heading corrected by the plugin?

Thanks and regards

Andreas
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Old 04-06-2019, 06:13   #48
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Re: Compass Deviation Plugin future requests.

What is OC please?


The manual is here https://opencpn.org/wiki/dokuwiki/do...s:deviation_pi
and there are links to how to calibrate a compass which should help.


Dirk is probably not available right now. Sorry.
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Old 04-06-2019, 08:25   #49
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Re: Compass Deviation Plugin future requests.

Hi,

OC = Opencpn for me, sorry

Iīm a little bit confused cause in the plugin itīs possible to activate a checkbox "send true heading to opencpn".
In the manual stand this on the to do list and itīs not clear if now this function is working or not.

I tried the plugin and it works but without sending true heading to opencpn.

So there are two possible things why:

1. This function does not work with the actual Version of this plugin
2. My Input filters block the (internal) nmea sentence. But the nmea sentence is internal so I wonder if so.

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Andreas
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Old 04-06-2019, 15:05   #50
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Re: Compass Deviation Plugin future requests.

Deviation Manual states:

Quote:
TO DO but on my list is re-sending a nmea headg (HDG) sentence including True North Course.
Also I have tested the check box and find no message is being shown in the Nmea Console.


We need users to test this plugin! Seriously!


Send your examples, questions and issues, please.
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Old 04-06-2019, 22:37   #51
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Re: Compass Deviation Plugin future requests.

Hi,

@rgleason: Right, this is the sentence of the manual I mean. This is the one witch confused me a little bit cause for me it was not so clear that this plugin canīt generate a true heading nmea sentence for opencpn yet.

As I wrote in this forum I use a home made heading sensor with a compass module and an arduino.
In the code I added a simple function for the devitation (just an array with 36 values -every 10° a value for the devitation). So when underway I compare the courses and can get the different values for devitation and with the arduino-software for the raspberry I can set theese values in the Array. So after some days of sailing I got a good working devitation sheet.

But with this plugin the making of the devitation sheet is much more comfortable.

Regards

Andreas
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Old 05-06-2019, 03:11   #52
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Re: Compass Deviation Plugin future requests.

Andreas, that is a pretty clever way to derive the deviations. Would you mind sharing your deviation data as an example for others? Perhaps attach here?
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Old 06-06-2019, 03:50   #53
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Re: Compass Deviation Plugin future requests.

Hi,

here there are my values for the deviations:

int devitation [] = {
8,8,8,-9,-8,-8,-9,9,5,2,3,3,3,5,5,2,0,0,4,-6,-6,-6,-3,-7,-7,-3,-2,-2,-2,-4,0,0,-2,-5,-10,8}; //Defines the devitation in 10 degrees steps

This is the line of the arduino code with the array for the deviations (the complete code is in the threat of the inexpensive heading sensor. The values are for every ten degrees (0 to 10 degrees is 8 30 to 40 degrees is -9)
But there are some faults in this array and itīs the array for my boat and compass.

Getting the values underway is not so simple, caus you mast be shure that there are no effects due to the wind or current. I sometimes use my Radar and the overlay to correct the deviation.

Regards

Andreas
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Old 06-06-2019, 05:44   #54
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Re: Compass Deviation Plugin future requests.

Thank you Andreas. Your Inexpensive Heading Sensor thread
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Old 07-06-2019, 06:12   #55
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Re: Compass Deviation Plugin future requests.

Andreas29,
I tried to enter your deviations at 10 degree intervals and the entry form does not seem to make much sense to me... Have I got some entry wrong here?


1. Enter the "Compass Course" 0, 10, 20, 30, 40 etc
2. Enter the "Compass Bearing" adjusting it so the "Deviation" is as you listed.
3. The result is the Compass Bearing seems way off.
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Old 12-06-2019, 06:33   #56
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Re: Compass Deviation Plugin future requests.

Hi,

as I wrote, there are some faults in the sheet. The jump from +8 to -9 at 30 to 40 degrees seems to be wrong.

General: The deviations that are listed above you can read on this way:
compass-course 0 to 10: Deviation 8 degrees (means if the compass shown 5 degrees the "really magnetic North" is 5+8=13 degrees
Compass-course 340 to 350 degrees: Deviation -10 degrees means that if the compass-course is 345 degrees then really magnetic North is 345-10=335 degrees

But I repeat, there are still some faults and I interchanged the +/- sometimes when I made the starting sheet with the deviation values. Now I adjust the values when Iīm underway to get a better deviation table.

I used and tested the deviation plugin and feed it with my values and I got a curve so this works.

Regards

Andreas
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Old 12-06-2019, 10:40   #57
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Re: Compass Deviation Plugin future requests.

Ok, so I am trying to get this right.

"compass-course 0 to 10: Deviation 8 degrees (means if the compass shown 5 degrees the "really magnetic North" is 5+8=13 degrees"

In the second screenshot I have entered:
Method: Bearing
Compass Course: 0 <--- Enter
Compass Bearing: 358.3 <--- Enter
True Bearing: 10
Variation: 3.7
Deviation 8.0 <--Result.
Is this the correct way to do it? Because as you get into later compass courses, the compass course and compass bearing seems to diverge way too much, in order to have the deviation results be correct.
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Old 12-06-2019, 10:50   #58
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Re: Compass Deviation Plugin future requests.

For example, this one seems ridiculous!!!
Method: Bearing
Compass Course: 200 <--- Enter
Compass Bearing: 2.3 <--- Adjust to get the right Deviation
True Bearing: 0
Variation: 3.7
Deviation: -6.0 <--- Result which corresponds values you have given.
This is just plain WRONG! The Compass Bearing should not be 2.3. It does not make any sense to me at all!

This plugin does not work properly IMHO. I think it is still early Beta ...Please show me why I am wrong and what I am doing incorrectly.
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Old 13-06-2019, 02:10   #59
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Re: Compass Deviation Plugin future requests.

Hi,

I think that the different fields "compass course" "compass bearing" and so on in the plugin are right but gives room for faults.

I have to decide if I use an other -different- compass bearing or the compass course as bearing (than they are the same).

So when I ride a 5 degree compass course the compass bearing is 5 degrees but the true heading then is deviation+variation+compass bearing:
E.g. 5 degrees compass course = 5 degrees compass bearing (the target is ahead), deviation is +8 degrees. With a Variation of 3,7 degrees true bearing then is 5 + 8 + 3,7 = 16,7

For 200 to 210 degrees e.g. 205 degrees:
compass course 205 degrees, compass bearing 205 degrees.
With deviation of -6 and variation of +3,7 true bearing then is:
205 -6 +3,7 = 202,7

I enter the values in the sheet and got my deviation table in the plugin when I tested the plugin last time. I didnīt know exactly how I did it but I thin I made it with the way described above. But I still got some probs with the plugin. The plugin just crashed when closing the deviation sheet. When this happend I have to restart opencpn. And the other is that the plugin donīt send true North to opencpn. So I test the plugin from time to time but not underway.

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Andreas
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Old 14-06-2019, 05:51   #60
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Re: Compass Deviation Plugin future requests.

Yes, I do find the plugin bombs out sometimes and is unfriendly in that way.
  • Fix to be more stable and operable.
  • Ability to adjust plugin table so it is bigger, and adjust the width of fields wider.
  • Selection of a field to edit is almost impossible, it selects anything but the highlighted field to edit.
  • Only way to edit another field is to Close the plugin, and bomb Opencpn out, then reopen. Very inconvenient.
  • When you close the plugin bombs opencpn every time!
  • Now sure new values are saved properly to a file until the plugiin is closed.
  • The actions the user is to take for data entry needs to be made clearer.
  • An illustration of how Compass Course and Compass Bearing are used.
  • If you have the deviation how do you enter data?
  • If you have True Bearing how do you enter data?
Andreas, using your explanation.
Method: Bearing
Compass Course: 5 <--- Enter (when range given is 0 to 10 degrees)
Compass Bearing: 5 <--- Enter (Same as CCourse when target is directly ahead)
True Bearing: -6+3.7+5= 2.7 (deviation+variation+compass bearing)
Variation: 3.7
Deviation: -6.0 <--- Result which corresponds values you have given.
Is this better?
I have to say that this seems pretty backward to me. We should be entering just the original data that we have available, not having to add up values!

Is this because you got actual Deviation values from you electronics? Whereas doing this the traditional way, we would have a list of Compass Courses and True Bearings?"


I think it should have a mode to enter Compass Course and Deviations directly.
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