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Topic: NMEA 2000 Shield (Read 149236 times) previous topic - next topic

simonfe

Hi Timo,

Many thanks for the guidance, I was looking in the wrong place and had not seen the flags! I will have a play later to test it out

re Termination of the bus, yes understood. In this application I will only have the two devices as it is on a small motor launch and has no multi drop bus, just CAN breakout wired straight to the MFD. I guess that the MFD has no internal termination resistor so perhaps I should reduce the value of the termination resistor on the CAN breakout? It is working ok with the termination 120R on the breakout board, so maybe not an issue. I will later fit the same to our sailing yacht which has a properly terminated multi-drop bus so will not fit the terminator on that installation.

Thanks again
Simon

timolappalainen

 I have not met any MDF with internal resistor. It would not be good. On test system with short bus, one terminating resistor is normally enough.

autopilotNOR

Hello Timo,

after a half year now I have found some time again to take a look into NMEA again. This also due to my Princess gets a "new" engine which needs again a digital interface.

We started beside selling diesel based heaters for boat and caravan. I was thinking about if it is possible to control the heaters through the protocol. From the library, I found the "tN2kTempSource" class. Like the name show, it is just a source.

So do you know about devices which can control the cabin temperature through the NMEA2K protocol? I could find yet something about this from my device, the Raymarine Axiom 9. Would be great if I could make an interface which then could control the heaters through some kind of panel or already existing multifunction device.

I am talking about this device https://marine-varmer.no/produkt/planar-2d-12-tm-3995-12v-2kw-pu27/ , please this is not meant as advertisement here. We do not sell outside NO,DK,SE as well. It would be also interesting to control warm water heater which we use the engine water heater for together with a tank.
There is also a SMS module which can turn on and control the heaters. With the right interface it should be able to control whatever device in from the NMEA2K network where it would make sense.

So do you know about devices which are able to controle heating systems, do you have an example like a panel which could be mounted several places on the boat to controle the things?

timolappalainen

I do not know any common device for controlling heaters. The problem is that there is no standard messages for that, so every manufacturer would use proprietary messages.

On the other hand there temperature PGN:s 130312 (obsolote) and 130316 could be used for tempretature control. They both has field "Set temperature", which can be changed by standard way with Complex groupg function PGN 126208. So in principle your device can provide Cabin current temperature and set temperature with 130316. Then with other device - e.g. MFD it should be possible to change set temperature field on your device and so your heater would start to heat. Unfortunately I do not know does MFD:s support that functionality or if any does, how complex it would be change set temeperature. I mean that it may be behind several click.

Also you can make your own control panel and use proprietary PGN:s. With that you only win that the cabling could be used and you can provide current cabin temperature to the N2k bus. But there is also marketing question about certification. Even my library is "certification ready" the costs for getting you device certified are some thousand dollars. So how meaningfull it is for customers if you sell your system just NMEA 2000 compatible instead of NMEA 2000 certified, if they should connect it with critical network with navigation systems.

It may be easier to make own control panel with some wireless solution .

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