Splitting NMEA 0183 output from plotter or use N2k gateway?

[Nos4r2]

I've got a 2002 Opti 225. It's got a fairly early smartcraft loom on it with an SC1000 speedo and revcounter, and no speed paddlewheel so the speedo doesn't work.

I'm wiring everything up at the moment. I've currently got an HDS7 gen 2 connected to a Standard Horizon GX1600E using the TX and RX NMEA 0183 cables from the HDS unit.
The HDS7 only has that one NMEA 0183 in/output.

The Smartcraft loom has an NMEA 0183 input on it Can I split the NMEA 0183 signal transmitted from the HDS7 to run the speedo?

Alternatively, would I be better off putting an NMEA 0183 to 2000 gateway in and running the Smartcraft off that? Would I gain extra functionality?

[Nos4r2]

Originally Posted by Nos4r2

Alternatively, would I be better off putting an NMEA 0183 to 2000 gateway in and running the Smartcraft off that? Would I gain extra functionality?

(or is it more likely to work!)

[Daniel]

You can connect two "listeners" to one "talker" without problem on nmea0183, so yes split the HDS7 output to smartcraft and the radio.

I would say crack on and see if it works before you worry about the following, you wont do any damage trying...

But if youre techie enough, check that the baud rates are the same. Smartcraft, from memory, is 4800. The HDS7 will be capable of fater speeds but the radio position input will probably be set 4800 so the HDS7 output will be set to 4800 so you should be OK.

If these speeds are OK and it still doesnt work, you need to check the HDS7 is outputting the speed sentance along with position (position must be working as the radio is working). GLL is position. VTG is ground speed.

[Nos4r2]

Cheers, yes the baud rates are the same-I found them late last night. Both 4800 if anyone else is looking for them.

It's good to know I can split the 0183 output-thanks If the HDS isnt outputting speed sentence, is there a way to make it do it that you know of?

Basically, I'm techie enough for most things, but I have the console in the garage at the moment and I can't check anything til it's all on the boat. It's far easier to get it right without having to lie on the floor with my head in a hatch.

[Daniel]

It's in the manual; pg 107 - menu twice to access settings, then network, then 0183 output.

The piccy suggests it might not support speed. I find this very hard to believe.

[Nos4r2]

Originally Posted by Daniel

It's in the manual; pg 107 - menu twice to access settings, then network, then 0183 output.

The piccy suggests it might not support speed. I find this very hard to believe.

Have a look at page 109.

Controls NMEA 0183 sentences used, allowing you to select the type of messages
your unit will transmit when communicating with other NMEA 0183 devices. The
default setting will work well under most conditions.
To access NMEA 0183 Output screen:
1. Select NMEA 0183 Output from the
Network menu and press enter.
2. Highlight a desired sentence and press
enter to turn it on/off.
3. To finalize changes, select OK and
press enter.

Basically you enable NMEA output, set the baud rate to 4800, and enable the following sentences RMB, RMC (for the SmartCraft) and GLL (for the VHF) though I think my VHF needs RMC as well on to show speed over ground on its display.

[Daniel]

RMB / RMC are bearing and distance to waypoint type information and as far as I am aware don't contain speed (but I don't have an nmea spec to hand)

Smart craft displays BTW and DTW and uses it to calc estimated fuel to waypoint. I always thought that was kewl.

I have always thought / used the VTG sentance for speed (VelociTy Ground)

[Daniel]

Can't you just get hold of a paddle wheel?

Then you get water speed on smart craft and ground speed on GPS, hence if you paid attention in maths you know the tidal speed with or against you.

Smart craft IIRC then lets you set a "swap" speed so the speedo uses SOG above a certain speed where a paddle wheel will stop being accurate.

[Nos4r2]

Originally Posted by Daniel

Can't you just get hold of a paddle wheel?

Then you get water speed on smart craft and ground speed on GPS, hence if you paid attention in maths you know the tidal speed with or against you.

Smart craft IIRC then lets you set a "swap" speed so the speedo uses SOG above a certain speed where a paddle wheel will stop being accurate.

I've already got 2 transducers going on the transom. Don't really want to go drilling more holes, and I really don't want to route another one under the deck.

[Techteam]

Fit an NMEA multiplexer it's not the cheapest option but allows several talkers/ listeners to be on the same wire.