Would like to hear from anyone using a scope to debug NMEA 2000 and J1939. Or Vehicle Bus Analyzer (LeCroy specialty accessory packaged scopes)

Thanks

There isn't much more yet. I'll know today as the factory rep is coming out. Unfortunately I can't be there.

1) I am mostly looking for consistency how people test these systems. What do you use? Do NMEA 2000 installers get scope training? I am looking for some consensus and acceptable advice on what an installer or rep should have and do use.

The real problem is the lack of test equipment needed by the installer (who is great otherwise and thorough) and the factory reps. I've spoken with the installer about this and the reps. Generally most boat people don't get trained in using oscilloscopes as vehicle bus analyzers. Very few have a CAN to USB data logger. There seems to be even less advice for Marine ethernet bus testing packet analyzers. No one I've talked to uses a scope, and one person quoted I can't afford $20,000. CANbus can be debugged with a used $200 scope off ebay.

2) My wife has stated I can't yet go there to check and fix (er...diagnose) it (It's under warranty and 90 miles away). "It's Become An Issue". The factory rep is coming to check on it with a new harness.

3) I "suspect" low is failing on the Crusader ECU's J1939. transients, or a bad harness. I also fail on the SyncNCruise (which is on the same harness but not CANbus) to set cruise. The Crusader ECU required specialty programming by the factory.

This is a specialty harness, rewired to work with Helmview. Sheesh ... harnesses! It appears properly terminated at the ends. The bus shows 60 ohms.

The FWmurphy Helmviews work (mostly) when only one is connected on the J1939 bus. They flash off, (BUT NO CAN ERROR MESSAGES SHOW). They work very inconsistently when both are connected. The things should be logging can errors. They are likely running in degraded 64Kbit mode.

So the advice I seek is what would you recommend that an installer have and a rep as tools?

I suspect that also, miswired harness or a bad ecu.

The FWmurphy Helmviews work (mostly) when only one is connected on the J1939 bus. They flash off, (BUT NO CAN ERROR MESSAGES SHOW). They work very inconsistently when both are connected. The things should be logging can errors. They are likely running in degraded 64Kbit mode Mode 7-9. Deutsch connectors and a harness (unshielded twisted pair). Fwmurphy owes me the full diagram showing both helmviews in a twin engine configuration. Both to both. It's a rewired harness.

One J1939 bus to both engines and both ECU's. J1939 is not an optoisolated bus.

The manual is here. http://www.crusaderengin...com/manuals/L510023.pdf It does not show the dual engine, dual Helmview configuration.

Helmview has 2 J1939 connectors, a modbus and NMEA2000 connector.
OK that's not the question I've asked.... Question I've asked is

---

FWmurphy was supposed to come today to check it out. They moved back a week due to a flight issue. I stopped the installer from shotgun debugging. They just sent a replacement harness which has not been installed, because throwing solutions at a problem ain't the way to do it.
I need to have another heart to heart with the installer.
So the advice I seek is what would you recommend that an installer have and a rep as tools?

I am trying to get the installer to buy the right tools. Effectively speaking, it's hard to get people to use the right types of tools.
What tools do you use to debug these systems?


What should an installer have aside from the obvious multimeter?
Do you use a scope for transients.... What kind? Is the scope set up a Vehicle Bus Analyzer?
What test harnesses do you have?
Do you use the N2KMeter by Maretron?
Do you have breakout boxes for debugging? Were you able to buy them?
How much would you spend?


The rep has not mentioned bringing a scope. Wasn't a scope part of the NMEA2000 training or is that in the ASE tests?

My personal tools are 3 scopes (2 100 MHZ oldies) and a 50Ghz Tektronix 11801C (also used for 10 to 1000Base T ethernet) and fiber optics TDR. A Kvaser leaf light CAN to USB for data logging et al, MATLAB. I am getting parts to build harnesses for the Deutsch and NMEA 2000. And the J1939 specs and coding skills.

I am familiar with Line Maintenance (AF/Space term) which is the process of getting the craft to work.

Normally, two things are required:

1) Test equipment that tests components that are not removable, such as the harnesses with their connections to power, etc.

2) Known-good Line Replaceable Units that can be swapped in place of the removable components. LRUs would be the helm control boxes, and control boxes on the engines themselves.

I would not expect a technician to make much sense of rise times and voltage margins, timing errors, and the like. I would expect him to test the installed cabling with a bus tester that determines that both connections and impedances are correct. Similarly, I would not expect the tech to recognize marginal signals coming from a control box. He should, however, be able to replace the box and rerun the system test to see if that box was the problem.

After the faulty LRU has been replaced, the known bad unit goes to a depot for Depot Level Maintenance. This is where it would be put on a bench, the covers removed, and a tech with specific skills looks at waveforms to determine the bad component. After repair, the unit gets the Factory Acceptance Test just like a new one, and can be returned to service.

I would expect that the Depot would be Murphy themselves, or a well-equipped shop, and that they would fix and return the box so as to get their own LRU back for return to their test kit.

If your technician isn't hooked into a maintenance process something like the above, then he is wasting time. Perhaps you should ask.

No, not at all.


There is no good choice. J1929 and NMEA 2000 are different. Yes they are both based on CANbus. Physically they can use different wiring, plugs, etc.

A boatyard is a completely different business than a automobile repair shop. For one thing, automobile manufacturers warranty the entire car and back up that warranty with training and specialized tools. In general boat manufacturers do not - simply because they do not have the same level of control over the components going into a boat as a car manufacturer does. It is an axiom in the business that no 2 boats are built the same. Boatyards repair a wide range of boats, not just one or two manufacturers boats.

Did you ask your boatyard whether they had ever installed your particular revision/configuration of Crusader engines together with FWMurphys particular revision/configuration of Helmviews in a boat exactly the same as your boat including the wiring harnesses, electrical distribution system, etc. I bet their answer was/is no. Has any boatyard done it anywhere in the country. Again, I would bet the answer is again no.

You are lucky that it appears that both Crusader and FWMurphy are willing to work with you on this issue rather than just telling you that you have an unsupported configuration.

Unfortunately impossible in this case since the engines have to be operational in the boat.

I agree with your comment on grounding issues - always a major issue for electronics on a recreational boat.



I am not sure it is the boatyards responsibility to make it work - unless the customer is prepared to pay for the time and effort involved in doing so. Did the customer specify the equipment? Was this a fixed price bid?

Right now, other than time, I am waiting on the manufacturer's rep and proper resources. In no case, is anything at issue yet, other than the boatyard needs to get the right resources to fix this.

In old OBDI you could use a multimeter to get out the trouble code (count the deflections). That wouldn't pass muster today.

I think NMEA 2000 and J1939 have changed the state of normal practice. I am not sure the ABYC has recognized that fully.

Sorry, but certification for Cummins diesels does not been that one knows anything about gas engines or, in reality, about J1939 other than how to use the Cummins diagnostic tools i.e. QUICKCHECK, INLINE, etc. Did you ask them which level/type of Cummins Certification thay had? There are a number of different levels and types.


Humm, ABYC electricial certification does not cover engines or engine control systems.


All boatyards are like independant repair shops. It is the nature of the business.


Was the entire system tested before installation on your boat?


But is it the first installation involving your particular version of ECUs and Helmviews?


Yes, of course.


What is there for ABYC to recognize? Engine control and monitoring systems are not within their remit. ABYC develops safety standards for boat building and repair.

IMHO, you are on a sticky wicket as regards who is one the hook for making it work. You have stated that you were the one who specified the system and where it was sourced from.

I've found that simple with a little mussle is better! I like my cable steering, maybe not when I have to replace cables, but for now is pretty good.

Roger

BTW: This is a great thread, disagreement on an intellectual level.



Murphy has been a lot of help and is excellent. It's a learning process for myself, the boatyard and Murphy. I chose this system because of the help available from the vendors. I stopped work temporarily because the boatyard got out of their depth, and didn't get back on track.

Rule 1: Don't fix it, if you don't know (or are reasonably sure) what the problem is.
Rule 2: There is no fixed price on old boats. The work contracted for will lead to work not contracted for in fixing supporting systems.

Oh brave new world, that has such boat networks in it.

Actually, it's classic wiring that is less reliable even when done right, with the right tools. When properly installed, and verified NMEA 2000 and to a lesser extent J1939 can bus is far more highly reliable (spaceworthy and airworthy as MILCAN). The difference is that the verifying an of installation is a electronics testing task, not just a physical testing. Most automotive shops have "LAB" scopes, like the wildly successful Snap-On Modis system.

I feel, It's important to NMEA2000 success that emphasis be placed on mature testing tools and techniques that are easy to use, aligned with ASE and available to the manufacturers, field reps, yards and boaters. That means more openness.

It's J1939 that's the challenge. It's almost the same, but different (no opto-isolation and not shielded).

After next year, most of the wiring will move to NMEA 2000 style to simplify it. I will have 3 buses (A - J1939, B NMEA2000 - as Navigation Data Bus, and C NMEA 2000 Lights and controls). I really want 2 NMEA 2000 buses from the 2 helm to the controllers. See http://powerandmotoryach...ectronics/0302magicbus/ or Thanks to fp http://www.albatrosscontrolsystem.com/ for the general concept.

FWMurphy and the boatyard have been very supportive and are very good. Murphy is coming out to work on the boat. I stopped the boat yard from continuing to work on the problem with multimeters, after 8 hours plus swapouts time more hours and as they pretty much exhausted that ability to debug. I admit, I didn't know about different levels of Cummins certification.

Since It's my money, It's cheaper to insist that expertise be brought in ( the factory reps and/or local ME experts with right tools). In no case, am I not paying for this at least in part.


Networks and the implications of Net-Centric Systems

Warning : Contains Theory. Currently boats are collections of systems, where the interaction between systems is on a physical rather informational level. Example: A fume sensor in the bilge connects to a fume sensor display made by the same manufacturer and to nothing else. A water sensor connects to an alarm board. Etc....

Under the Albatross system, I would have different sensors connected to a common module connected to a network. (I suspect that USCG (CFR) regs will need to be updated deeply to reflect netcentric concepts.) Because this is a system of systems, I can depend on a display and alarm system to show warnings. This is a disruptive technology to the marine industry, as it cannot avoid the supply dependency it has on the automotive industry and therefore must change to networked systems. Modern engines and the supply chain behind them fuel this change. Once I chose modern networkable engines, much of the additional change is implied.

There is a new concept called a NetCentric system, where systems engineering focusses on the network as the enabling technology for the boat (platform). Communications with systems are network oriented (not just between the boat systems but integrated with wireless, AIS, Marine Radio, Satellite, radar).

Once NMEA2000 and J1939 are in the boat systems as networks, we could say the system is NetCentric, where the primary characteristic of the system is the network (tons of this is on www.incose.com). The boat does not function with out a network as part of a System of Systems (SoSE)- . http://en.wikipedia.org/wiki/Netcentric The INCOSE (www.incose.org) groups are wrestling with the new testing, and techniques that SoSE implies. http://www.incose.org/pr...tivities/wg/netcentric/

fpmurphy: In what way is my specifying Crusaders a risk on my part? Diesels were originally planned for but came in as too expensive. Am I supposed to say put engines in the boat, but not specify the kind of engine? In Virginia as a common law state, there is merchantability and implied use laws as well as the state's dept of inland fisheries which licenses marine repair shops. (BTW: I might be scr*wed in Florida.)

You are correct in that I am at risk on competency, so that as long as the correct process of repair (sans negligence) is followed, the non-negligent competency is not enforced. This is where my pocketbook has to drive.

Effectively training for a boat mechanic spans ABYC, NMEA and ASE task lists. ASE/NATEF task lists spell this out and it's a part of the alignment that should be better advertised by the organizations. The Marine Mechanics Institute (UTI) includes this competency model in the training of mechanics. A starting point for how much is changed in simple electrical testing on boats (much less electronics is Ed Sherman's book reviewed here. BTW: The use of a scope is definitely in the competencies of an engine mechanic per ASE, and is included in MMI training.