DF300AP NMEA: unplugging fuel flow causes ALL system alarm indicators

[tnole23]

i searched and read everything i could find on nmea with suzukis, and didn't find anyone experiencing my issue. if i missed, feel free to copy me the link.

so, i added a simrad mfd to my boat when it had the old engine. also added the garmin(i think garmin) in line fuel flow sensor, and that was my nmea network. along with a power(battery switch) drop of course. few weeks ago i had the DF300 installed and they left my network alone and created another for the suzuki gear, engine interface, c10, power(ignition). after discussions with installer, he gave me the yellow power isolator T to connect the networks. of which i did. when i did that i also added the simrad fuel level sender, which i added to my old network. so i have two networks connected with the power isolator, one side is the suzuki interface and c10 on ignition power, on the other side of the isolator is the mfd, fuel flow, fuel level, and battery switch power. everything updated as found by the mfd on internet, but some come back as "current version info not available", so maybe that's not really updated to latest version, not sure. all seems updated tho.

now the problem. i was reconfiguring things to use the engine data for fuel info, instead of the flow sensor i already had installed, so i could remove it. so i unplug it and put the appropriate terminator on. i power up everything, and right after the c10 loads up all the alarm indicators come on. fuel, engine, temps, the yellow triangle with exclamation point, looks like all of em. doesn't seem to affect anything, but it's weird. if i plug the fuel flow back in, they all go away. if i leave it all on, and then unplug it, they'll stay off, until i cycle the power. if i power it up with it plugged in, then unplug it, they stay off, again until cycling power. so there's a specific sequence i can do to get it on without alarm indicators, but somehow the fuel flow is causing issues.

i've gone through all the settings and didn't see anything that could look like a fix. any ideas?

[Moonlighter]

Weird.

But .... if you remove a device drom a network, you unplug it from its T and then remove that T from the backbone. There is nowhere to add another terminating resistor when you do that!!

Is that what you did??

Have you double checked the device connections - remember, devices only go to the leg part if a T, and the only thing that goes to the top part of a T is another T or a backbone cable between top of one T and another, or a terminating resistor at an open end.

But in any case, why would you want 2 “halves” in your network arrangement?

There is no reason why your Simrad display cannot be on the same network as the engine, none at all! In fact it will give your C-10’ s a speed source to allow them to calculate mpg.

I would suggest keeping things simple and just going with one consolidated network. In effect, all you will be doing is adding one standard network T tp the Suzuki “side” and getting rid of everthing else on the other side that the Garmin in line fuel flow sensor is on, including the isolating T. Make sure to add the terminating resistor back on the end T.

[tnole23]

Weird.

But .... if you remove a device drom a network, you unplug it from its T and then remove that T from the backbone. There is nowhere to add another terminating resistor when you do that!!

Is that what you did??

Have you double checked the device connections - remember, devices only go to the leg part if a T, and the only thing that goes to the top part of a T is another T or a backbone cable between top of one T and another, or a terminating resistor at an open end.

But in any case, why would you want 2 “halves” in your network arrangement?

There is no reason why your Simrad display cannot be on the same network as the engine, none at all! In fact it will give your C-10’ s a speed source to allow them to calculate mpg.

I would suggest keeping things simple and just going with one consolidated network. In effect, all you will be doing is adding one standard network T tp the Suzuki “side” and getting rid of everthing else on the other side that the Garmin in line fuel flow sensor is on, including the isolating T. Make sure to add the terminating resistor back on the end T.

i've done both, with regard to removing and terminating. i've completely removed the t, and moved the terminator to the socket that that t was just plugged into, to terminate it without the flow sensor t. and i've also removed just the flow sensor plug, and terminated the t on the drop socket, which made that t have two terminators, one on drop socket and one on backbone socket. both did same thing.

i actually had the backbone on the "leg" part when messing with things and it was working fine, but i changed it in case it mattered. all drops are on the "leg". only backbone cables, other t's, or terminators are on the backbone socket.

the 2 halves was simply for power. the network is connected, the isolator just makes it so the mfd and fuel things are powered when batteries are turned on, c10 and engine interface only when key is on. i personally like it that way, but if it's causing a problem i can change it, but considering it's just the one drop, doesn't seem like that'd be it. i DO get all the suzuki data on the mfd, and mfd data on c10, so they are talking.

i'm no nmea expert, but i feel like i understand the concept. but this makes no sense. almost seems like it's not temrinating properly, but i've actually had the flow sensor plugged in and had the terminator off, and it didn't cause the alarms. i don't know if it makes sense cuz i don't know nuances of nmea stuff, but it could it be the flow sensor is selected as source for something, and when i unplug it's causing errors? i went through fuel and engine settings where i saw the fuel related stuff, and didn't see the flow sensor still selected for anything, i did have to select engine interface for a few things.

hope something i said cues u in to what could be wrong.

[Moonlighter]

It still sounds like something is incorrectly installed. Do you have anything connected to the Garmin isolating T’s leg, it should only have other T’s connected to the cross sides. The leg should not be used as far as I know.

The MFD (Simrad) doesnt get its operating power from the network, so that is no reason to have it separated from the engine side.

The only device you have on the second half that needs network power to work would appear to be the fluid level (tank) sensor - and do you REALLY need that to work when the engine is off?

Another alternative power supply arrangement is to use a Suzuki dual power node that provides the network with power from the engine key and if that is off, another switched power source.

Have you tried a different terminating resistor? Checked that the ones you have are the correct ohms?

NMEA devices send data that in lay terms is coded and each bit of data has a discrete identifier. Called a PGN. Having 2 devices on a network sending the same pgn data, in this case fuel flow, is likely to cause network conflicts.

Try my suggestion of consolidating to one simple network and see where that gets you.

One other comment - whenever a device is added to or removed from a network, its good practice (and may well solve data source issues) to reset network data sources so the network knows what it is now dealing with.

To do this, turn ALL devices on the network on, including turning the engine key to on (where it beeps, but doesnt need to be running). Then in one of the C-10’s, open the menu/system/network and you should see an option there or under device list to auto-select data sources. Select that option and do it.

[tnole23]

It still sounds like something is incorrectly installed. Do you have anything connected to the Garmin isolating T’s leg, it should only have other T’s connected to the cross sides. The leg should not be used as far as I know.

The MFD (Simrad) doesnt get its operating power from the network, so that is no reason to have it separated from the engine side.

The only device you have on the second half that needs network power to work would appear to be the fluid level (tank) sensor - and do you REALLY need that to work when the engine is off?

Another alternative power supply arrangement is to use a Suzuki dual power node that provides the network with power from the engine key and if that is off, another switched power source.

Have you tried a different terminating resistor? Checked that the ones you have are the correct ohms?

NMEA devices send data that in lay terms is coded and each bit of data has a discrete identifier. Called a PGN. Having 2 devices on a network sending the same pgn data, in this case fuel flow, is likely to cause network conflicts.

Try my suggestion of consolidating to one simple network and see where that gets you.

One other comment - whenever a device is added to or removed from a network, its good practice (and may well solve data source issues) to reset network data sources so the network knows what it is now dealing with.

To do this, turn ALL devices on the network on, including turning the engine key to on (where it beeps, but doesnt need to be running). Then in one of the C-10’s, open the menu/system/network and you should see an option there or under device list to auto-select data sources. Select that option and do it.

lots of good options, and of course the answer was in there. it was a configuration issue when adding the two networks together that had already been powered up and selected default devices. powering everything up and doing "auto select" reset all the default devices and removed invalid ones, and solved my issue.

with regard to your hookup comment, i think it's more of a product of the network i had prior to repower, than needing level isolated with mfd. i had originally had network under console, installers put new one behind instrument panel, so it was just easier to run one trunk line between the two than rewire everything to behind instrument panel. but now that i removed fuel flow, the only thing hooked up right now is fuel level and the power drop, so i could just run the fuel level cable up and remove the power drop, and really consolidate that way. i do kinda like having level indication without turning key on, not really for any particular reason other than just to know. but that's all just cleanup stuff, i just wanted it working mainly.

any, thanks for input. helped narrow things down and get it all sorted out.

[Moonlighter]

Ok good its sorted.

file the “auto select” for data sources away in your memory banks, as a useful problem solving technique when data missing and similar issues arise in future.