SC-70 interfering with Air Temp data (Airmar 220WX)

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msandrew

New member
Have discovered that along with the position & orientation data that the SC-70 broadcasts onto the N2K backbone as expected, it also has minimally-documented Air Temp & Pressure functionality it also broadcasts (PGN 130311).

Am trying to figure out how to turn off this Environmental data, it interferes with the data being sent out by my weather instrument (Airmar 220WX). As a Furuno device, other Furuno devices give its data priority over 3rd party devices.

For example, the FI-70 display has no ability to choose the source N2K device for Outdoor Air Temp, so if that data is on the backbone from multiple sources, it defaults to the SC-70.

Has anyone else experienced this? Is there a way to turn off this PGN broadcast?
 
My suggestion would be to change the NMEA 2000 instance number of the SC70 to a higher number (lower priority) than the 220WX weather sensor so that the weather sensor is the priority data picked up and used, then go into the NavNet and pick the SC70 as your primary heading source so that it's heading is used and not the 220WX. This way the weather data will be like you want and so will the heading.
 
Not an instance issue. The problem is that when you ask for Air Temp displayed on the FI-70, there is no way to specify a source device for Air Temp. The Furuno display prioritizes data sent by a higher end Furuno device like the SC-70 over the 3rd party Airmar device.

The SC-70 uses updated Environment PGNs, the Airmar uses the older PGN. Another reason the displays prioritize the “better” PGNs.

The solution suggested by Furuno is to avoid the N2K drop direct to the backbone, and instead output the SC-70 data in 0183 format from one of its COM ports via a converter onto the backbone. This way, I can choose what SC-70 data i want into the N2K network, filtering out the environmental PGNs.
 
Yes, I would recommend an actisense interface so you have the needed customization. Sounds like a good solution.
 
Johnny, You may be able to steer me in the right direction here. If I want to replicate by using 0183 sentences the info normally sent via N2K, without duplicating and putting too much extra crap on the backbone, how do I know which 0183 sentences to send? There are 30 different 3-letter 0183 sentences the SC-70 can transmit, some of which seem to duplicate data. Am familiar with my equipment, but not completely sure exactly what data from the SC-70 was being used by each of them (AIS, MFDs, Autopilot).
 
I have an SCX-20, which also transmits air temperature and barometric pressure PGNs and an Airmar WX220. Since I am using them with TZT 3 MFDs only and not an FI-70, I can select the data source.

However, my observation is that the air temperature values from the SCX-20 are very close to the Airmar sensor reading and quite accurate. Do you see a big disparity?

There is probably a better way to do what you want than going with 0183 by creating a second isolated NMEA 2000 backbone and a device like this component from Yacht Devices: https://www.yachtd.com/products/nmea_bridge.html
 
I have TZT2s (3 of them), and I noticed that when I tried to specify the 220WX as the preferred source of weather info, the TZT would default to the SC-70, just like the FI-70s do. I think there are Furuno-proprietary identifiers that Furuno devices prefer.
 
msandrew":t136y011 said:
I have TZT2s (3 of them), and I noticed that when I tried to specify the 220WX as the preferred source of weather info, the TZT would default to the SC-70, just like the FI-70s do. I think there are Furuno-proprietary identifiers that Furuno devices prefer.
Click to expand...

That's interesting. Mine don't do that. The source selection will stay on the Airmar sensor if I choose it. Perhaps there is some difference between the SCX-20 and SC-70 software that is responsible. The SCX-20 setup menu allows turning off output of the temperature and pressure PGNs in any event, which must not be the case with the SC-70 or that would have been an easy solution for you.

You could do that externally with the Yacht Devices bridge that I mentioned in my earlier post.
 
The SC-70 is an IMO professional device. Tech support says it does stuff automatically that can’t turn off because its IMO.
 
msandrew":1us13gtg said:
The SC-70 is an IMO professional device. Tech support says it does stuff automatically that can’t turn off because its IMO.
Click to expand...

While that's true, the instance of the SC-70 via NMEA2000 can be changed using a Maretron N2K tool. Perhaps if you had a Maretron gateway you could change the instance to a higher value like Device Instance 1 or 2 and see if that resolves what seems to be potentially a NMEA2000 instancing conflicts IMHO.

Just a thought, :sail

- Maggy
 
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