smis to sds

[fishingteach]

I know from reading your NMEA network info in the sticky thread that you can create your own smis to sds cable. Is it possible to create this cable with a y configuration? One side feeds the nmEA network the other side feeding the new Suzuki SMG4 gauge? That way you could run the new gauge and analog gauges also.

[BowansReward]

As an IT engineer my guess is no! Tthe gauge will use 2 way communication with the ECU ruling out a Y splitter (conflicting inputs). A less elegant solution that I'm using, so that I can feed SMIS data to my chartplotter & also use SDS diagnostics when required. I've run the SDS output to my helm & have a switch box (4 gang 2 way switch). Normal setting SMIS <> Chartplotter when switched to position 2 SMIS <> SDS port on the side of the helm

[Moonlighter]

I had this discussion about running the new SMG4 gauge and anaolgue gauges at the same time with my friend who is a Suzuki dealer and master level technician. His initial reaction was twofold-

No it cant be done, and
why would you possibly want to do it?

But anyway after a bit of bemused discussion.....

We concluded that it may be possible to achieve this by running a separate harness from the analogue plug on the ecu, from there up to the dash, and connecting a second gauge harness there. But to his knowledge, nobody has attempted it, and to be honest, we both wondered why on earth you would really contemplate doing it....

What some people who are new to Suzuki engines dont know, is that the engine’s ecu has 2 outputs via separate connectors - one is the output for standard signals that go to analogue gauges, and the other plug (the SDS plug) is the one that sends digital data that is used by the new SMG4 gauge (and any other NMEA2000 displays) as well as by the Suzuki Diagnostic System for engine servicing activities.

So the main wiring harness from the engine to the throttle box and to the dash for gauges etc is connected to EITHER one of those plugs, depending on which gauges will be used. Therefore the data that goes up via the harness is suitable for only one kind of gauge, either the digital/NMEA2000 gauges, or analogue gauges, NOT FOR BOTH.

[fishingteach]

I understand about the 2 different types of signals and the 2 circuits. I am going to be running analog gauges due to the design of my dash. I am also running the Suzuki interface to my Lowrance using the SMIS to SDS cable. My question was just asking if you could build a harness with a y in it to run the new SMG4 gauge as well as feed digital signal to the NMEA network with info for the Lowrance.

[Moonlighter]

I understand about the 2 different types of signals and the 2 circuits. I am going to be running analog gauges due to the design of my dash. I am also running the Suzuki interface to my Lowrance using the SMIS to SDS cable. My question was just asking if you could build a harness with a y in it to run the new SMG4 gauge as well as feed digital signal to the NMEA network with info for the Lowrance.

You dont need to make a Y harness!! You’re trying to solve a problem that doesnt exist, because.....

The SMG4 gauge has a NMEA2000 plug on the back that outputs all available engine data to the network which can then be displayed on any compatible display, including your Lowrance. It also allows the SMG4 to receive GPS and depth data from the Lowrance and to use GPS data to calculate fuel economy.

I was and am still confused as to what you have in mind, and how the SMG4 gauge fits into your plans?

So you run analogue gauges, but want engine data to the Lowrance - easy. Interface cable run to the SDs plug and then to the network. Piece of cake. Effectively, you are saying that analogue is your base preference for gauges, but you want the benefit of digital data to your MFD’s. Well established protocols for doing that.

But where does the SMG4 gauge fit into that equation?? And why??

As per my first reply, the problems may happen when you try to mix SMG4 and analogue at the same time. Untried protocols as far as I know, and its hard to imagine why you might want analogue, NMEA2000 shared to chartplotter AND SMG4 digital all at once... but perhaps you have a reason and I look forward to hearing more to explain the thinking. Always ready to learn new things!

[fishingteach]

I am repowering my triton 21hp bass boat. It had a mercury optimax with analog gauges, some of which were multiple gauges in one (tach and trim, speedo and fuel). The shape of the dash does not allow for installing the SMG4 where the round analog gauges were. I don't necessarily want to leave my lowrance on the gauge display while running because I like to leave it on the chart then. I was just thinking about a way to leave certain pieces of engine data like fuel usage on the SMG4 or other display while leaving the lowrance on the chart. The old smis and c10 gauges ran off of the nmea network and would've made this a lot easier. I have installed an analog tach, trim and water pressure gauge. I do not want an analog fuel gauge or speedo. I had installed the smis gauge but later found out, thanks to the help of this forum and bass boat central, that it wouldn't work with the 250SS I am getting ready to purchase new. I was just curious about a way to do this but if it can't be done then I will just run it on the lowrance and analog gauges. I do thank you for your help. I know that my repower is different than most. I have learned a lot in this process.

[Moonlighter]

Ok got it.

I’d suggest shelving the idea of the SMG4 and instead of the normal interface cable, consider the new Suzuki Connect interface cable for Navico displays. This cable gives you everything than a normal interface cable supplies, plus it integrates with your Lowrance display to give you full functionality of a custom Suzuki dashboard on the instruments page, plus all fault and service codes will pop up on the screen.

Then consider just using the Suzuki analogue tach, it also has the warning lights at the bottom, and these show you fault codes and service reminders by blinking in various sequences. I agree speedos are a waste of time. Along with your water pressure and trim gauges, that has you well covered.

Then on the Lowrance you have some simple options. As well as the Instruments page (the one that looks like a dashboard with several gauges etc), on the Lowrance you can add engine data overlay items to any page!

So, for example on your chartplotter page, you could add SOG, engine temp, fuel used or fuel remaining, and say one other item. These appear down the LHS of the screen and you can adjust their size from small to large. I do much the same on my HDSGen 3. Works a treat.

That way you still get the full chartplotter page plus the most important engine data to you that you want to watch regularly. Easy to do. Doesnt clutter up the screen hardly at all.

The fuel data from the Suzuki is usually very accurate. Once youve confirmed the accuracy you can be comfortable that it will stay accurate. just remember to do the refuel process in the Lowrance every time you add fuel, its very quick and easy.

You can also add a NMEA2000 fluid level sensor that connects to the tank sender unit and then display tank level on the Lowrance if you want. But really only necessary if its likely that you could have fuel stolen from your tank. Otherwise the fuel remaining data from the Suzuki reliably tells you what you need to know.

[Moonlighter]

If you post a photo of your dash layout might also be able to suggest other options. I found a couple of photos online and it looks like some people have their MFD screens flush mounted in the dash and others have them on a swivel bracket. But there do seem to be a couple of different dash layouts depending on model/year.

You can of course run a C-10 with the interface cable I mentioned in my last reply too.