Problem interfacing Tacktick NMEA to Standard Horizon CP300

[CarlR]

Hi
Has anyone else managed to link together a Tacktick NMEA interface box to a Standard Horizon CP300 ( or CP180 ) chartplotter, with the NMEA sending speed transducer information?

I have linked VHF and AIS without any issues.

The problem I am getting is that the trip information displayed on the plotter is wrong. It often says e.g 50nm after only 30 minutes! With the Tacktick turned off, the GPS is fine.

The Tacktick is sending VHW and VLW data sentences. The CP300 manual states that it can take VHW but does not mention VLW. Tacktick say that you cannot configure it to not send data. Standard Horizon say that you cannot filter out messages and think that it is the VLW that is corrupting the calculation of trip distance.

The speed transducer was stuck for a while so I'm not ruling this out as a cause ( but will have to wait until boat back in the water to check ).

I have a call out to Standard Horizon to see if I can turn off all the input from the Tacktick ( but still keep the output ) without having to disconnect the cable.

If anyone else has managed to get this to work then any help prior to re-launch would be much appreciated.

Thanks. Carl. Vancouver 274.

 

[aluijten]

There is a service menu on the CP300 where you can diagnose some of the CP300 interface features (turn on while pressing another key). In this menu you can see all the messages that are sent from the Tacktick system.
VLW is the distance traveled through water. Basically your log reading. You did not mention for the 50nm you speak of, weather this is GPS distance or Water distance. I assume it's water distance. If so there might be a unit of measure problem. By looking at the diagnose screen you might find some clues.
You can use "http://www.nmea.de/nmea0183datensaetze.html#vlw" to help you understand the messages you see.
There are devices for sale that can modify the NMEA message so it will fit your plotter, but at a price!
If it's any help to you, I've hooked up my CP300 to a Autohelm ST50 system and this works excellent, so it's not an impossible thing to do, I'd say.

Cheers,

Arno

 

[Leighb]

I have TackTick instruments linked to STH CP 500, all works fine. I did not fit it myself, done by local electronics guy, but it obviously can be done.

 

[CarlR]

Hi Arno

Thanks for the reply.
I dont know how to tell whether the 'trip' distance that the CP300 shows the GPS data or the data from the tacktick. With the Tacktick turned off, it must show GPS distance and this matches with a handheld backup.

Is the service screen you talk about the NMEA page where you can see the messages being sent in. If so, I agree that when back in the water, I should note down exactly what this says for the VLW. From what I know about the data sentence, all information ( total cumulative distance and trip distance ) should be in nautical miles. I could see if there is an option in the Tacktick that is sending this in some other format?

My CP300 is interfaced to VHF and AIS fine - its just the tacktick instruments.

I was hoping that someone who has the same equipment might be able to tell me that their installation was ok.

 

[CarlR]

Hi LeighB

Do you have any network diagrams of what your electronics chap did so I can check my cables match? Do you get STW and depth information onto the CP500 as well as GPS data being fed to the tacktick displays?

Many thanks.