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sycrumble · 28-04-2018, 10:14

Hi Sailors,
my name is stefan, just registered and need help with ocpn. I want to make a depth offset - is that possible?
The momentary displayed depth is 1,7 m, we are in the harbour, the depth of the boat is 1,9m...

Anybody here who can help?

Greetings, Stefan

transmitterdan · 28-04-2018, 10:25

This is done with your depth transducer, not OpenCPN. The transducer manual will tell you how to adjust the offset.

billknny · 28-04-2018, 10:30

Actually, this has nothing to do with the "transducer" and looking in the transducer manual is not going to be a very helpful suggestion.

The instrument display that is processing the depth information is where the depth offset is going to be found.

hoolie · 28-04-2018, 10:38

You're possibly both right as it depends on the transducer drive and signal processing connections.

Stefan, can you please give us more information about what equipment and instruments you have and how it is connected to OpenCPN?

sycrumble · 28-04-2018, 10:51

Ah yes of course.
I have the Airmar DST Triducer. There is nothing to set on it. It is directly connected to the NMEA2000 network. I use a Furuno FI-70 Multifunction display. There i also have to set an offset for STW and depth...
The network is connected to the pc with an actisense NMEA to USB converter.

I hope the situation is more clear now.

transmitterdan · 28-04-2018, 11:25

Airmar have software that can adjust the transducer offset. That’s the right way to do it then you don’t need multiple offsets in various displays.

offpist · 28-04-2018, 11:39

If you have an Raymarine I70 you can set up the transducer from there.

hoolie · 28-04-2018, 12:42

Quote:

Originally Posted by transmitterdan

Airmar have software that can adjust the transducer offset. That’s the right way to do it then you don’t need multiple offsets in various displays.

The Airmar WeatherCaster software can update sensor firmware, including DST800, and do certain calibrations. I don't know about DST800 but I can set offsets for my HS2183 heading and attitude reference.

You will of course need a way of connecting a PC to your sensor ...

sycrumble · 28-04-2018, 13:33

Quote:

Originally Posted by hoolie

The Airmar WeatherCaster software can update sensor firmware, including DST800, and do certain calibrations. I don't know about DST800 but I can set offsets for my HS2183 heading and attitude reference.

You will of course need a way of connecting a PC to your sensor ...

I loaded it, nice tool. But it seems that there is no communication possible trough the actisense converter, only works in one direction, nmea 1083...
i have got 2 instruments, and one pc running opencpn.
Is it not possible to make the offset in ocpn? I don´t want to buy another converter.

rgleason · 28-04-2018, 14:00

Could nmeaconverter be used?

hoolie · 28-04-2018, 16:19

I think it could, though obviously it will only apply to OpenCPN dashboard, not the other two instruments.

In my case I have a version of the heading sensor that uses NMEA0183 so there's no problem connecting a PC to set it up. Do Airmar have any suggestions on how to connect their N2K sensors to a PC? It would need specific PGNs, particularly for firmware updates, and most converters like the Actisense are only programmed for a small subset.

My H2183 actually has dual NMEA0183/N2K outputs, though my cable is only NMEA0183. Does the DST800 also have dual outputs? If so then a modified cable (at horrendous cost from Airmar) could give access to the NMEA0183 PC interface.

transmitterdan · 28-04-2018, 17:33

If this is a needed feature of OpenCPN add it to the feature tracker found at the OpenCPN.org web site. It would not be hard to add this feature to the connections dialog.

jean_pfoumf · 29-04-2018, 01:08

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

hoolie · 29-04-2018, 01:55

Quote:

Originally Posted by transmitterdan

If this is a needed feature of OpenCPN add it to the feature tracker found at the OpenCPN.org web site. It would not be hard to add this feature to the connections dialog.

Mmm, I think it may be a bit more complicated. To be effective it probably would need a "calibration" plug-in to able set individual sensor scaling and offsets. These should be sent back to the sensor so the calibration is available to all its connections.

However it has been pointed out on here that at least the Raymarine i70 and the Furuno FI70 already provide this function so a plug-in would generally not be needed.