OSTC3, cR, sport and 2 :  heinrichs weikamp forum The fastest message board... ever.
OSTC's running hwOS 
OSTC Sport - Compass issue
Posted by: mapoubelle ()
Date: February 10, 2019 08:21PM

Hello,

Currently on diving holiday I wanted to use the compass of my OSTC sport instead of my suunto compass... but it seems that the compass has an issue.
During yesterday's dive, the compass was always showing the same bearing independently of the direction sad smiley
I did a calibration and today... got again some issues at the second dive.

When looking at the picture below, it is clear there is an issue: turning the compass of 90° changes the reading from 102° to 260° (cfr orange band for reference).

OSTC Sport #10369 FW10.41



Edited 1 time(s). Last edit at 02/10/2019 08:34PM by mapoubelle.

Attachments: IMG-2019.jpg (98.9 KB)   IMG-2020.jpg (69.4 KB)  
Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: Ralph ()
Date: February 11, 2019 06:27PM

Hi,

the reply of the first-level support would be: have you done the compass calibration correctly? This issue pops up here with certain frequency... The trick with the calibration is that the OSTC needs to be turned around all its 3 axis, it's easy to forget one of them. If you do this and stay away from lager magnetic/metallic objecs while doing it, an accuraccy of say +/- 5° is archivable. Good luck! In case it still doesn't do, second-level Support will be activated... ;-)

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: mapoubelle ()
Date: February 11, 2019 09:04PM

Yes, I did around the axis.
Wondering if this could be caused by a low battery... The battery failed 3 dives later and the OSTC even skipped the last dive entirely (cfr the other posts I made).

I replaced the battery, I will redo a calibration and see what happens.

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: heinrichsweikamp ()
Date: February 12, 2019 08:42AM

mapoubelle Wrote:
> I replaced the battery, I will redo a calibration
> and see what happens.

Also make an update here to the 10.51. newer versions also show the calibration values in the menu. These can indicate if there is a hardware problem or not.

regards,
Matthias

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: mapoubelle ()
Date: February 24, 2019 10:08AM

Hello,

The problem remains. Re-calibrating helps for a limited period of time.
How can it be determined if its a HW issue ?

Pic1: some time (1day) after calibration
Pic2: new calibration
Pic3: reading after calibration

Thanks in advance!



Edited 1 time(s). Last edit at 02/24/2019 10:10AM by mapoubelle.

Attachments: 1.jpg (183 KB)   2.jpg (167.7 KB)   3.jpg (169.6 KB)  
Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: Ralph ()
Date: February 24, 2019 10:50AM

Hi,

regarding Pic1: "some time after calibration, compass heading always shown as 0°" - when entering the calibration menu in this situation, do the x,y,z values read all zero? If yes, calibration was lost, so it would be a software / operating issue.
There's also a 10.52 firmware available since yesterday, but be aware: updating firmware may also reset the calibration data.

BR
Ralph

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: mapoubelle ()
Date: February 24, 2019 01:59PM

OK, I am back home.. wil upgrade, re-calibrate and let you know the evolution

Br,
J

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: UKG ()
Date: March 04, 2019 02:30PM

Hello everyone,

as I had similar issues as mapoubelle describes above I’d like to chime in here. Maybe I am not doing the calibration correctly. I understand I need to rotate the OSTC around all three axes. Does it make a difference how much I move the OSTC horizontally/vertically during the calibration? Is it beneficial for the calibration, if I try to rotate the OSTC around all three axes while trying to hold the OSTC at the point where all three axes meet?

Another question in this regard: What do the values for “Cal X” “Cal Y” and “Cal Z” tell me? (see mapoubelle’s Picture 2 above where the values are -512, -47 and -1406)

Thanks and best!
Uli

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: Ralph ()
Date: March 04, 2019 07:27PM

Hi Uli,

rotating around all three axes is paramount, linear movements do not matter. You can turn around each axis individually or do combined turns, that does not matter. Turning around each axis individually and for similar durations may be easier in terms of not forgetting one axis.

The compass sensor gives the heading where its "needle" points to, in 3D coordinates. Unfortunately this heading is not given by the earth's magetic field alone, but by the overlay of the earth's field and by another magnetic field that is largely caused by the battery inside the OSTC. So for operational use, this erroneous OSTC own-produced heading component must be subtracted from the combined heading that the sensor delivers. While calibration, this erroneous heading component is measured: while you are turning the OSTC, the sensor is continiously read and its heading values are continiously added up (in 3D mathematics). While proper turning, from the OSTC point of view, the earth's magetic field is equally dispersed in every direction over the time, so at the end of the summing-up it averages itself out. What remains in the averaged result is the erroneous heading component, as its source is fixed to the OSTC and thus turns with it. The calibration values shown are nothing else than the 3D coordinates of this erroneous heading component that have been found in the calibration run.

All clear now?
:-) Ralph



Edited 1 time(s). Last edit at 03/04/2019 07:30PM by Ralph.

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: UKG ()
Date: March 05, 2019 10:44AM

Hi Ralph,

thanks for the elaborate response!

Almost all clear, now winking smiley If I get your explanation correctly, the 3D coordinates “Cal X” “Cal Y” and “Cal Z” cannot be influenced by the user anyway, right? I had the impression that these values become bigger, if I do larger linear movement while calibration, but that might just be my impression, I did not verify this.

However, I am wondering why the OSTC shows these values to the user. What practical information can I deduct from these “Cal X” “Cal Y” and “Cal Z” values? From your explanation I assume that should all three be "0" the calibration did not work properly, but is that all?

Best
Uli

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: heinrichsweikamp ()
Date: March 05, 2019 11:22AM

UKG Wrote:
-------------------------------------------------------
> However, I am wondering why the OSTC shows these
> values to the user. What practical information can
> I deduct from these “Cal X” “Cal Y” and “Cal Z”
> values? From your explanation I assume that should
> all three be "0" the calibration did not work
> properly, but is that all?

We added this to be able to give better support via mail. When these are all zero -> Not calibrated and if they are on odd values like "-4096" for all axis we can tell that there is some kind of hardware issue with the compass.

Also: When properly calibrated these values are (almost) identical with each calibration for the same unit using the same battery.

regards,
Matthias

Options: ReplyQuote
Re: OSTC Sport - Compass issue
Posted by: UKG ()
Date: March 05, 2019 11:36AM

Got it. Thanks, Matthias!

Options: ReplyQuote


Sorry, only registered users may post in this forum.
This forum powered by Phorum.