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Old 07-09-2021, 02:08   #16
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Re: Wind Instrument

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Originally Posted by skipmac View Post
I'm surprised that losing the wind instruments, even though on the backbone, shut down everything, including the compass light? How the compass light?

At least the Garmin plotter at my helm will work just fine with or without the N2K cable connected. Would certainly lose the AP but think I could get that back pretty easily by isolating just the AP components.

Wind I installed a B&G system last year and it has been bulletproof. Of course I'm mainly interested in the basics and not the detail and accuracy you want so can't comment on that aspect.

It's obviously a short in the power supply part of the backbone.


The compass light was a coincidental fault, which has been on the repair list for a while.


Yes, the plotter at my helm works fine without the network. As I wrote, it even has a failover internal GPS.
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Old 07-09-2021, 04:34   #17
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Re: Wind Instrument

Depending on which B&G system you install the terminator may or may not be at the mast head.
The Triton 2 system has a terminator at the MHU. The H5000 has the terminators in the boat with drops from the MHU into the CPU. The hydra system has speed and wind going into the CPU, the CPU is connected to the NMEA bus. The Hercules system only has wind going into the CPU.
Having a terminator at the mast head could be problematic if the MHU is a failure point.
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Old 07-09-2021, 04:38   #18
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Re: Wind Instrument

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Originally Posted by Joli View Post
Depending on which B&G system you install the terminator may or may not be at the mast head.

The Triton 2 system has a terminator at the MHU. The H5000 has the terminators in the boat with drops from the MHU into the CPU. The hydra system has speed and wind going into the CPU, the CPU is connected to the NMEA bus. The Hercules system only has wind going into the CPU.

Having a terminator at the mast head could be problematic if the MHU is a failure point.
Yes, I think it's a bad idea to run the N2K network up there. If Triton wind requires that, I wouldn't have it. But I'm not considering Triton wind anyway. If not the CV7 racing version, then the proper tall (and alas very expensive) racing one.

I'm tired of messing around - I want valid true wind. I realize that will cost me some money.
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Old 07-09-2021, 14:32   #19
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Re: Wind Instrument

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Originally Posted by Dockhead View Post
Yes, I think it's a bad idea to run the N2K network up there. If Triton wind requires that, I wouldn't have it. But I'm not considering Triton wind anyway. If not the CV7 racing version, then the proper tall (and alas very expensive) racing one.

I'm tired of messing around - I want valid true wind. I realize that will cost me some money.
Again I have not read the specs but I'm fairly confident in asserting that they will have a "fan out" spec which will specify the maximum power draw for each device included in the network and a maximum total power draw. Any infringement on this spec increases the probability of data transmission performance degradation.

The system specs will also probably include maximum lengths for the backbone and droppers. The designation difference between the two being dictated by the presence, or not, of a terminating resister.

So, one is working within the constraints of the maximum allowable length for the backbone and the maximum allowable length for a dropper. Consequently, if the distance to and up the mast exceeds the maximum length for a dropper then one would designate the leg up there as backbone and, if a terminating resister is not included in the comms circuit of the device, fit a T and a terminator.

However if the distance up the mast is within the spec for maximum dropper length and one wished to retain the option of extending the network beyond the mast base junction, treating the mast leg of the network as a dropper and without a terminating resister (either internal or external) is an option.

The terminators are just a resister which inclusion is to govern power distribution and characteristics within the data Transmission system (Be mindful that in comparison to NMEA 0183 this is a fairly sophisticated, bi directional, comparatively high data rate system)

The purpose of the inclusion of power conductors in the NMEA 2000 cabling system is prioritized to provide reliable and clean power, independent of individual device requirements, to the data transmission system in order to keep it's operating integrity and performance within system specs. Whilst the specs may allow it I'm fairly sure that there would be strict limits placed the draw of any non comms systems sharing power from the comms system source to keep it within the fan out limits.

The above is all inference on the part of a dumb old roughneck but knowing how the minds of engineers work I'm fairly confident of it complying with reality and that's the way I'd design it anyway.

So, the path to good system operating reliability would appear to be, good connections by keeping water away from the conductors and their joints and not loading the comms system up with other than comm system electrical loads.

How would one best achieve this.

Like many of us I have experienced the "crowded conduit" problem whereby running power cables to the the number of devices I fit in my boat far exceeds the builders perceptions of adequate cable conduit capacity.

Have pondered on the problem I decided that running separate, high current capacity, house and nav ring mains around the boat and switching on the negatives of the appliance using MOSFETS via a multi cored data cable would be a solution.

This scheme might also serve in providing power and switching power to devices installed up the mast. A single power conduit to all the lights and instrumentation installed up the mast with a multi core data cable to switch power via a solid state relay or MOSFET on the negative of each device.
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Old 08-09-2021, 05:07   #20
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Re: Wind Instrument

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Originally Posted by RaymondR View Post
Again I have not read the specs but I'm fairly confident in asserting that they will have a "fan out" spec which will specify the maximum power draw for each device included in the network and a maximum total power draw. Any infringement on this spec increases the probability of data transmission performance degradation.

The system specs will also probably include maximum lengths for the backbone and droppers. The designation difference between the two being dictated by the presence, or not, of a terminating resister.

So, one is working within the constraints of the maximum allowable length for the backbone and the maximum allowable length for a dropper. Consequently, if the distance to and up the mast exceeds the maximum length for a dropper then one would designate the leg up there as backbone and, if a terminating resister is not included in the comms circuit of the device, fit a T and a terminator.

However if the distance up the mast is within the spec for maximum dropper length and one wished to retain the option of extending the network beyond the mast base junction, treating the mast leg of the network as a dropper and without a terminating resister (either internal or external) is an option.

The terminators are just a resister which inclusion is to govern power distribution and characteristics within the data Transmission system (Be mindful that in comparison to NMEA 0183 this is a fairly sophisticated, bi directional, comparatively high data rate system)

The purpose of the inclusion of power conductors in the NMEA 2000 cabling system is prioritized to provide reliable and clean power, independent of individual device requirements, to the data transmission system in order to keep it's operating integrity and performance within system specs. Whilst the specs may allow it I'm fairly sure that there would be strict limits placed the draw of any non comms systems sharing power from the comms system source to keep it within the fan out limits.

The above is all inference on the part of a dumb old roughneck but knowing how the minds of engineers work I'm fairly confident of it complying with reality and that's the way I'd design it anyway.

So, the path to good system operating reliability would appear to be, good connections by keeping water away from the conductors and their joints and not loading the comms system up with other than comm system electrical loads.

How would one best achieve this.

Like many of us I have experienced the "crowded conduit" problem whereby running power cables to the the number of devices I fit in my boat far exceeds the builders perceptions of adequate cable conduit capacity.

Have pondered on the problem I decided that running separate, high current capacity, house and nav ring mains around the boat and switching on the negatives of the appliance using MOSFETS via a multi cored data cable would be a solution.

This scheme might also serve in providing power and switching power to devices installed up the mast. A single power conduit to all the lights and instrumentation installed up the mast with a multi core data cable to switch power via a solid state relay or MOSFET on the negative of each device.



My installation fulfills the N2K spec. Maretron has a fantastic network design tool which allows you to confirm all of that.


The reason NOT to do this is NOT because you will violate the spec, but because WHY? Why risk the whole network with such a long run of cable and an unreachable termination? Why put all that heavy cable up a 23 metre mast? It's just WRONG. And it concretely bit me in the posterior (I have a broken finger to show for it, even). So I'm not doing this and don't recommend to others.
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Old 08-09-2021, 05:22   #21
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Re: Wind Instrument

Our bus is made from mini cable, our drops are micro. The mini cable can handle 9 amps. The micro drop to the mast head is about 100', we've not had problems with it.
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Old 08-09-2021, 07:22   #22
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Re: Wind Instrument

The backbone is normally jointed at several locations. Providing there is a suitable joint in an easily accessible location below deck, a failure of the wind instrument or the NMEA backbone cabling leading up the mast should not be a significant issue to the rest of the system.

In the event of a fault that brings the total NMEA down, unscrew the backbone leading up the mast and screw in a termination resistor.
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Old 08-09-2021, 07:58   #23
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Re: Wind Instrument

The most likely failure mode that would disable the whole NMEA system is a short in the power leads of the backbone. In this case, as I have indicated, it should be easy to manually isolate this part of the system.

If you are are concerned about the reliably of the backbone cable leading up the mast, a device such as this will automatically isolate the power to the part of the backbone with the short (by blowing the fuse), but leave the rest of backbone powered.
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Old 08-09-2021, 08:00   #24
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Re: Wind Instrument

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Originally Posted by noelex 77 View Post
The backbone is normally jointed at several locations. Providing there is a suitable joint in an easily accessible location below deck, a failure of the wind instrument or the NMEA backbone cabling leading up the mast should not be a significant issue to the rest of the system.

In the event of a fault that brings the total NMEA down, unscrew the backbone leading up the mast and screw in a termination resistor.
Exactly.
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Old 08-09-2021, 12:17   #25
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Re: Wind Instrument

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Originally Posted by noelex 77 View Post
The most likely failure mode that would disable the whole NMEA system is a short in the power leads of the backbone. In this case, as I have indicated, it should be easy to manually isolate this part of the system.



If you are are concerned about the reliably of the backbone cable leading up the mast, a device such as this will automatically isolate the power to the part of the backbone with the short (by blowing the fuse), but leave the rest of backbone powered.
Certainly, but why would I do this workaround? When I can just terminate the network at the mast step and bring some nice light, thin, flexible 0183 cable down the mast?
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Old 08-09-2021, 13:26   #26
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Re: Wind Instrument

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Certainly, but why would I do this workaround? When I can just terminate the network at the mast step and bring some nice light, thin, flexible 0183 cable down the mast?

This is a valid option, but then you need a NMEA 0183 to NMEA 2000 converter (if you have a modern boat with other 2000 devices). These devices add an extra failure point.

Any wired wind instrument needs two wires for power and at least two wires for data (sometimes a ground is also needed). This is true for NMEA 2000 and NMEA 0183. NMEA 2000 protocols are stricter than NMEA 0183 and typically the wire, especially the power cable component, is thicker despite the wind instruments having a similar power consumption in each case.

If desired, the wire thickness on NMEA 2000 can be reduced to a similar level to the NMEA 0183 network if the 12v power feed is injected so that it feeds both the masthead cabling and the rest of the system. Thus the voltage drop in the masthead cabling does not impact the rest of the system. However, this cabling therefore uses a bundle of very thin wires. Typically these are around AWG 22 size. These very thin wires are also used on NMEA 0183 systems. The risk is that these may become unreliable over time when fed up the mast. For a racing boat trying to save weight this is a sensible solution, but for a cruising boat slightly thicker cable is arguably a better long term solution. You can use the thinner cabling similar to NMEA 0183 on a NMEA 2000 system if you wish. I would suggest in this case a dual power injection point similar to the device in post #23, but as this is a purely passive wiring device therfore it should be more reliable than NEMA 0183 to NMEA 2000 converter.

In summary, if you have a NMEA 0183 or a NMEA 2000 wired wind instument it needs a cable with at least four wires to transfer data and power. Wires fed up the mast and potentially subject to flexing and chafe are difficult to make 100% reliable.
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Old 08-09-2021, 14:24   #27
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Re: Wind Instrument

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This is a valid option, but then you need a NMEA 0183 to NMEA 2000 converter (if you have a modern boat with other 2000 devices). These devices add an extra failure point.
Indeed, I have a failed Raymarine one in my shed. Works great for an hour and then stops allowing data from the ST60 instruments NMEA Seatalk through to the Seatalk NG network and RM chart plotter. Replaced by a new converter and it all works perfectly, for now. A spare ST60 wind arm useful to keep the instrument running.

A completely separate older Garmin CP gives enough redundancy to complete a coastal voyage even at night.

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Old 08-09-2021, 14:52   #28
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Re: Wind Instrument

My radar has the option of connecting with a cable or having the N2K connection via WiFi. I don't know how well it works because I did not put the dome up the mast preferring to have it on a hinged pole on the transom.

I'm of the school which believes that believes that using NMEA 0183 and a converter is not a good plan because it still requires wiring up the mast and adds another complex electronic failure point.

I don't like connectors in poorly accessible places, particularly up the mast and generally cut them off and make a sealed splice in their place. Bit of a nuisance to remove a long run of cable but generally better in the long run.
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Old 09-09-2021, 00:54   #29
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Re: Wind Instrument

Quote:
Originally Posted by noelex 77 View Post
The backbone is normally jointed at several locations. Providing there is a suitable joint in an easily accessible location below deck, a failure of the wind instrument or the NMEA backbone cabling leading up the mast should not be a significant issue to the rest of the system.

In the event of a fault that brings the total NMEA down, unscrew the backbone leading up the mast and screw in a termination resistor.
How do you do that when you're alone on deck in a gale (or single handed) and the failure has brought the whole network down including the pilot?

Quote:
Originally Posted by noelex 77 View Post
This is a valid option, but then you need a NMEA 0183 to NMEA 2000 converter (if you have a modern boat with other 2000 devices). These devices add an extra failure point.

Any wired wind instrument needs two wires for power and at least two wires for data (sometimes a ground is also needed). This is true for NMEA 2000 and NMEA 0183. NMEA 2000 protocols are stricter than NMEA 0183 and typically the wire, especially the power cable component, is thicker despite the wind instruments having a similar power consumption in each case.

If desired, the wire thickness on NMEA 2000 can be reduced to a similar level to the NMEA 0183 network if the 12v power feed is injected so that it feeds both the masthead cabling and the rest of the system. Thus the voltage drop in the masthead cabling does not impact the rest of the system. However, this cabling therefore uses a bundle of very thin wires. Typically these are around AWG 22 size. These very thin wires are also used on NMEA 0183 systems. The risk is that these may become unreliable over time when fed up the mast. For a racing boat trying to save weight this is a sensible solution, but for a cruising boat slightly thicker cable is arguably a better long term solution. You can use the thinner cabling similar to NMEA 0183 on a NMEA 2000 system if you wish. I would suggest in this case a dual power injection point similar to the device in post #23, but as this is a purely passive wiring device therfore it should be more reliable than NEMA 0183 to NMEA 2000 converter.

In summary, if you have a NMEA 0183 or a NMEA 2000 wired wind instument it needs a cable with at least four wires to transfer data and power. Wires fed up the mast and potentially subject to flexing and chafe are difficult to make 100% reliable.
None of the high end wind instruments is native N2K. The LCJCapteurs units are native 0183 and you use the "Windy Plug" converter to get an N2K interface. The B&G ones need to be connected to an H5000 or another B&G box belowdecks before you can get N2K out of them (or even 0183).

Using a thinner N2K backbone cable in the mast is even worse than what I have now. As you said -- cables in the mast are subject to flexing and chafe. In the future I will not expose my entire network to the potential failure there, even if I can resolve such a failure by isolating that section, and I don't recommend it to others. The ability to isolate the section is of no comfort if your whole network including pilot goes down in a gale when you are alone on deck in the dark, as happened to me last month (result broken finger). If I had run the 0183 cable down the mast as the maker intended, I would have only lost the wind instrument instead of the whole network.


Yet another reason not to extend your N2K network up the mast -- it is not so easy to even find the fault in an N2K network when all the devices are theoretically working. It took me two days of hard grafting at sea, in rough sea conditions, to finally figure it out. The fault turned out to be an intermittent short in the power supply part of the network somewhere up the mast, most likely at the connector. This fault would bring the whole network down or different devices would be thrown offline. The one device which was always working was the wind instrument, so I didn't expect the fault to be up the mast and unfortunately checked that last. Maddeningly, some device or combinations would go offline, and I would isolate that or them, but then the fault persisted, throwing other devices off.



I now understand that the network should be kept as compact as possible, and complexity is not actually your friend. And if I do have another boat or do an electronics refit to this one, I will consider a standalone pilot instead of or in addition to my networked one. When you're single handed and need to step away from the helm to solve some problem, you need the pilot to work.
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Old 09-09-2021, 01:00   #30
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Re: Wind Instrument

Do A and T have any useful advice/products?
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