Voltage spike on NMEA 0183

[DickB]

Hi all,

I have had a failed AIS and the vendor believes that there was a voltage spike or ground loop on the NMEA 0183 circuit. Has anyone ever experienced this or heard of it happening?

Has anyone had an AIS fail on them before? I really did not expect this and there were no thunder storms in the vicinity at the time so I am at a loss (financially as well :-( )

The NMEA 0183 is directly connected to a RayMarine E120 chart plotter. Nothing else is faulty (VHF, chartpotter etc) but the AIS just died one day (in August!).

Thanks

Dick

 

[PaulRainbow]

Hi all,

I have had a failed AIS and the vendor believes that there was a voltage spike or ground loop on the NMEA 0183 circuit. Has anyone ever experienced this or heard of it happening?

Has anyone had an AIS fail on them before? I really did not expect this and there were no thunder storms in the vicinity at the time so I am at a loss (financially as well :-( )

The NMEA 0183 is directly connected to a RayMarine E120 chart plotter. Nothing else is faulty (VHF, chartpotter etc) but the AIS just died one day (in August!).

Thanks

Dick

Tell him to get lost and demand he sort it out, he's talking nonsense. Small claims is easy enough to initiate. How old is the AIS ?

 

[Norman_E]

Voltage spike seems very unlikely. Read the NMEA0183 guide published by Actisense if you can find it on their new website, I have failed. It explains that different vendors of NMEA 0183 equipment have used different connection standards, with some equipment using the 12volt ground wire as part of the NMEA 0183 circuit. In that case I would expect that damage caused by a ground loop would have happened when the connection was made, not at a random time thereafter. I think there is a distinct whiff of bullshit in the supplier's answer. Is your kit still under warranty?

 

[PaulRainbow]

Voltage spike seems very unlikely. Read the NMEA0183 guide published by Actisense if you can find it on their new website, I have failed. It explains that different vendors of NMEA 0183 equipment have used different connection standards, with some equipment using the 12volt ground wire as part of the NMEA 0183 circuit. In that case I would expect that damage caused by a ground loop would have happened when the connection was made, not at a random time thereafter. I think there is a distinct whiff of bullshit in the supplier's answer. Is your kit still under warranty?

That's been the case since day one of NMEA 0183, Garmin (for one) did it on just about everything, never caused a problem.

 

[MikeCC]

I expect there are lots of unexplained deaths of electronic kit that are never resolved. Which model AIS?
Is the cable connecting the AIS to E120 a good quality screened twisted wire data cable? If not, could be a source of unwanted spikes.
Have you connected anything else to the port since? You can check it's working by making a loopback connection between send and receive and looking at the NMEA receive buffer. Need some output set up of course.

 

[lw395]

It seems possible.
So the vendor is saying his kit is not terribly robust to loops and spikes.
The interface chip should be replaceable cheaply?

 

[lpdsn]

Is the cable connecting the AIS to E120 a good quality screened twisted wire data cable? If not, could be a source of unwanted spikes.

I never realised twisted pair was part of the NMEA0183 standard though.

Kit is generally opto isolated, but off the top of my head I'm not sure if that is mandatory.

 

[DickB]

Hi there,

I don't think there was any induced current as you might get say from lighting as no other bits of kit have been affected. Everything else works fine, and has done since August 12th when I found the fault on the AIS.

It is under a two year limited warranty and is 18 months old. The company is adamant that the NMEA 0183 output interface is blown through a high voltage but they have not defined what that constitutes. (It appears that the guarantee is now null & void. They have me over a barrel!!!)

I find this hard to fathom as all the other stuff works. My response was that the circuitry is either a frail design or there is a faulty PCB. My words seem to have fallen on deaf ears.

The E120 cable is RM's own and is shielded and only a couple of feet long. It connects directly to the AIS.

It has been a very tedious conversation with the manufacturer.

I'll keep the forum up to date with progress...

cheers,

Dick

 

[pvb]

What's the make & model of the AIS?

 

[DickB]

Voltage spike seems very unlikely. Read the NMEA0183 guide published by Actisense if you can find it on their new website, I have failed. It explains that different vendors of NMEA 0183 equipment have used different connection standards, with some equipment using the 12volt ground wire as part of the NMEA 0183 circuit. In that case I would expect that damage caused by a ground loop would have happened when the connection was made, not at a random time thereafter. I think there is a distinct whiff of bullshit in the supplier's answer. Is your kit still under warranty?

The kit has worked faultlessly for 18 months. In June I added a VHF splitter but I don't think that should have affected anything - It worked fine up until it didn't!!!. Yes there is a limited warranty which they are not honoring as they say the fault is due to high voltage! Very upsetting! The retailer thought they would supply a replacement but was told latterly that they would not. :-( I don't think the retailer was terribly impressed by this service!

 

[Martin_J]

It is under a two year limited warranty and is 18 months old. The company is adamant that the NMEA 0183 output interface is blown through a high voltage but they have not defined what that constitutes.

I assume for them to say that the output interface is blown, they've had the equipment back and tested it.

Did they send it back to you?

Like others have said, there's usually opt-isolation on the inputs and outputs. As lw395 says, perhaps if you have the broken unit back you'd not lose anything by taking a close look at the circuit and replacing the opto-isolators yourself .. or seeing if sbdy here can replace them. The parts are usually quite cheap.

I know it doesn't help with the fact that it's broken... but might be fixable, even if only as a spare.

 

[MikeCC]

I never realised twisted pair was part of the NMEA0183 standard though.

Kit is generally opto isolated, but off the top of my head I'm not sure if that is mandatory.

Data cable is often twisted pairs by default. Manufacturers seem a little coy about whether ports are opto-isolated. Raymarine NMEA apparently is.

 

[matthewriches]

What unit do you have?

 

[pvb]

What unit do you have?

I already asked that, but no response. Seems he wants to be coy about it.

 

[DickB]

I already asked that, but no response. Seems he wants to be coy about it.

I am not into naming and shaming. I am sure the manufacturer believe that their product is perfect and that by some means or another the unit was exposed to a "high" voltage.

At the moment I am trying to get more information from them about the fault and how they came to their conclusion. To shout from the tree tops their name is unlikely to improve relations. Sorry....

Dick

 

[DickB]

Thanks for your help everyone. I know a bit but not that level of detail... Thanks again.

Dick

 

[pvb]

I am not into naming and shaming. I am sure the manufacturer believe that their product is perfect and that by some means or another the unit was exposed to a "high" voltage.

At the moment I am trying to get more information from them about the fault and how they came to their conclusion. To shout from the tree tops their name is unlikely to improve relations. Sorry....

But you might find that other forum members have had problems with the same mysterious bit of kit, which would strengthen your hand in attempting to achieve a solution. Frankly, you ought not to be spending your time talking to the manufacturer, your contract is with the retailer and you'd be better off just claiming a refund from the retailer based on the product not being fit for purpose. If you bought it using a credit card this process will be even easier.

 

[laika]

I am not into naming and shaming. I am sure the manufacturer believe that their product is perfect and that by some means or another the unit was exposed to a "high" voltage.

Less about naming and shaming and more about determining if the product is "NMEA certified" which implies that it follows the NMEA's electrical standards which would possibly resolve the "is it opto-isolated?" questions.

 

[Jungle Jim]

I would't give up on this, keep pressing the retailer. This sounds like hogwash to me.

Whether the interface is opto-isolated or not the interface chips most likely to be used are designed to handle spikes and the board design should limit the ability of those to damage anything (top EMC immunity design specs are to 8000 volts,even poorly designed kit should be 2000). I can't think of much on boat that will generate that unless you have any old heavy duty 3-phase industrial motors on board that you switch on and off a lot

 

[RichardS]

If you bought it using a credit card this process will be even easier.

I would have also thought a Section 75 claim would be successfully but I started my first S75 against HSBC Credit Card about 3 months ago and have since then exchanged many forms, emails and phone calls costing me many hours .... and we are still without £2500 and any goods whatsoever to show for our expenditure.

The latest email from HSBC yesterday explained that they have contacted the retailer and that since the retailer "is not denying that they will provide a refund, it is difficult to establish a valid Section 75 claim."

I have emailed them back today with "It does not matter whether ************** Ltd have denied that they intend to make a refund or not. The fact is that they have not made a refund. How many more months are supposed to pass before HSBC accept that we are not going to receive a refund?"

I have given clearly stated that I intend to file a claim against HSBC with the Financial Ombudsman and report the retailer to the Police for theft but HSBC have just dismissed this with a "do as you wish" comment.

Section 75 requires a lot of paperwork and, in my experience so far, is a complete waste of time and one would probably be better of spending the time on Small Claims which I have always found to yield the right result.

Richard