Depth Offset

[sycrumble]

Originally Posted by GordMay

Greetings and welcome aboard the CF, Stephan.

Thanks, it´s nice here. A few years ago i quit all other forums regarding the behavior in it. (Tone...)
But my first impression of the "CF" is another thing. International, helpful.

[transmitterdan]

Originally Posted by jean_pfoumf

All the offsets can be calibrated from Furuno FI70 : System menu

This only adjusts the Furuno display but not other devices using the same sensor data.

[sycrumble]

Originally Posted by jean_pfoumf

All the offsets can be calibrated from Furuno FI70 : System menu

Yes, this is what i know. But it doesn´t calibrate the sensor. It changes nothing in ocpn.
I believe that i must use a NMEA 2000 Gateway instead of my actisense. My actisense is the NGW-1, it converts from NMEA 2000 to USB (NMEA0183).

The needed converter is actisense NGT-1. It costs about 200,-, don´t know if updating the sensor using airmar weather cast really works with the actisense NGT-1.
So the easiest way seems for me to set the same offset in every connected device. I have 2 Multidisplays --> that works, and opencpn --> searching for a solution.

[transmitterdan]

Crumble,

You have found one of the frustrations with NMEA2000 systems. There are standard messages for certain common data such as depth and wind speed. But different manufacturers are allowed to invent their own private messages for things like calibration and data adjustments. Therefore it is difficult to mix different brands on the same system without running into the problem you have found.

Raymarine don't make their own depth transducers anymore so they get them from Airmar. Most modern Raymarine displays use NMEA2000 and have the software to calibrate an Airmar sensor. You might find a friendly neighbor with a Raymarine and they could help you calibrate your sensor.

Airmar also sell a display device that can do the calibration of all their sensor devices.

[hoolie]

... ... and opencpn --> searching for a solution.

The NMEA Converter plug-in should what you want. You can modify NMEA data in and out as required. This has now been released as a beta.

[jean_pfoumf]

Actisense NGW-1 converts NMEA0183 to NMEA2K and vice-versa, so you would be able to use AIRMAR Weather Caster. Actisense drivers are installed with Airmar software.

[rgleason]

NmeaConverter

[sycrumble]

Originally Posted by rgleason

NmeaConverter

Sorry, but that is too much for me, cannot do it.
Where is the plugin?

[sycrumble]

Originally Posted by jean_pfoumf

Actisense NGW-1 converts NMEA0183 to NMEA2K and vice-versa, so you would be able to use AIRMAR Weather Caster. Actisense drivers are installed with Airmar software.

All the relevant fields regarding adding offset or calibrate are grey... It seems that the Sensor doesn´t communicate trough the converter, at least not completely.
This is what i see. When i go to offsets, I can´t do anything. Sensor isn´t known.

[jean_pfoumf]

Can you see your Actisense NMEA device in "Interface communications Setup" (port COMxx) ?

[rgleason]

Rasbats version of Pavel's Survey_pi (unreleased) seems to work with a few little glitches. I could crash it when changing values in Preferences, but otherwise I think it works.
There is no documentation for it yet See Survey_pi so maybe someone could provide that. Rasbats repository is here

[sycrumble]

Originally Posted by jean_pfoumf

Can you see your Actisense NMEA device in "Interface communications Setup" (port COMxx) ?

No, I can´t.

[jean_pfoumf]

I suppose that you select NMEA0183 in Communications Interface Setup window ?

[rooiedirk]

Originally Posted by hoolie

The NMEA Converter plug-in should what you want. You can modify NMEA data in and out as required. This has now been released as a beta.

Sorry but this won't work. For a data offset you would be resending the the same (adjusted) sentence, and O can't know witchone to use.

[rgleason]

So maybe you could run two instances of Opencpn, with the first one doing the conversion and sending it on to the second instance.

Another idea is to filter out DPT but somehow get it to nmeaconverter. Then create a DBT in nmeaconverter that OpenCPN would not filter out.

http://www.catb.org/gpsd/NMEA.html#_dpt_depth_of_water
DPT
1 2 3 | | | $--DPT,x.x,x.x*hh<CR><LF>

Field Number:

1. Depth, meters
2. Offset from transducer, positive means distance from tansducer to water line negative means distance from transducer to keel
3. Checksum

1 2 3 4 5 6 7 | | | | | | | $--DBT,x.x,f,x.x,M,x.x,F*hh<CR><LF>

Field Number:

1. Depth, feet
2. f = feet
3. Depth, meters
4. M = meters
5. Depth, Fathoms
6. F = Fathoms
7. Checksum

In real-world sensors, sometimes not all three conversions are reported. So you night see something like $SDDBT,,f,22.5,M,,F*cs

Originally Posted by rooiedirk

Sorry but this won't work. For a data offset you would be resending the the same (adjusted) sentence, and O can't know witchone to use.