Showing posts with label NMEA. Show all posts
Showing posts with label NMEA. Show all posts
Saturday, 30 July 2016
Engine NMEA 2000 crap
"Really, that's all I need, just the gateway kit, how much is it? Ouch $250 bucks? Well it is what it is, I guess, and the owner wants to see his engine instruments on his chart plotter." Fast forwarding a week UPS delivers me a box, and I go to the boat. Avidly ripping open the box, I behold the kit before me. There it is in all its glory, a small black box with an LED, and two cables coming out of it. Yep, one of them has a standard NMEA connector, and the other one has a what? It's a nine pin female connector, where the heck does this thing plug into? Wait a minute, it's a kit remember, and in the bottom of the box is another cable, with a nine pin male connector. I plug it in, and then look closely at the other end. Hmmm, it's a male 4 pin connector. Whats this plug into? I can see the entire engine harness, the engine gauges, the control computer, and the device bus, and nowhere is there someplace this four pin connector can go. Rats!
I call the engine builder's tech support department. "What's up with this kit? I can't plug this into anything, and I know what it's supposed to be plugged into. It's not going to fit without a saw." "Well you must have bought the wrong kit then, because if it was the right kit, it would plug in." "Sorry, but I want to politely disagree, the instructions specifically say it's for this exact engine configuration." "Maybe you should just take your boat to a certified dealer, they have been trained to do this sort of technical work." "Listen, it shouldn't require a $100 per hour technician to push in one plug, something must be missing from this kit I need to make it work." "Okay, let me check with someone, hold please. Okay, we don't get a lot of calls about this, but you need another cable." "Another cable? What does that do?' "Well it plugs into the pigtail in the kit that was plugged into the cable from the gateway, and then that cable plugs into the bus." "We sell them separately because we don't know what length you will need." "Okay, but why don't you just put the right bus connector on the gateway cable in the first place, and if you need more cable, sell extension cables that plug into that?" "I don't know I just work here, a 6' cable is $80.00, here is the part number." Okay thank you very much, I will order it from a dealer."
As an example, since when is this cable really worth $120? Seriously, you gotta be kidding me, a NMEA connector on one end, and a Yamaha bus connector on the other. But when it's only made by one company, the sky must be the limit. I should really be in the cable business.I can't tell you how many hours I have spent trying to get all of the right parts to do an engine interface. Yes I'm smarter now, but only with one scenario, and I don't really know whether this one will work yet. We will find out next week when I get the cable that plugs into the pigtail, that plugs into the cable that is attached to the little black box. What's so frustrating is that so few engine manufacturers post any real information online, and their tech support departments can be vague also. Unfortunately more than a few dealers are clueless, and the online forums are rife with out of date information and part numbers.
Yamaha - Command Link Plus gateway about $250 + extension cable starting at about $80. The original Command Link gateway is similar, and I don't know if the single cable still works, or you now have to buy the gateway.
Mercury - (Merc Monitor gateway) for up to 4 engines $900. It appears to be a complete kit. A pricing ouch, but you do get a pretty gauge with it.
Honda - No gateway required, cable only starting at $70.00.
Suzuki - No gateway required, cable only about $100.
Yanmar - Newer engines standard NMEA 2000 cable only.
Cummins - Could never figure it out, and neither could the Cummins' people I spoke to.
Volvo - No pricing on their online store website, and none found online.
Regardless how the engine companies choose to package, price, and sell the NMEA 2000 interface, it would be nice for all of them to clearly spell out how it's done, and what you need to do it. It would really be better for all if you engine dudes just simplified, and made the NMEA 2000 interface standard. Some of you get it, some don't. I'm taking the aluminum hat off now, and pouring a glass of whine.
Sunday, 24 July 2016
Field replaceable NMEA 2000 connectors
It's was the stereo installer dudes who caused the problem. There are now two new speakers installed on each side of the T-top's electronics box. Their enormous size driven by two amps now assures the owner that the USGS's seismographs will register every time they are used. Unfortunately the auto stereo dudes didn't realized the single NMEA 2000 cable they tie wrapped their big wiring bundle to couldn't take the strain and the connector's pins were pulled out.
No big deal for me, work is work. The wire pull is torturous, so I'm going to use a Molex field replaceable NMEA 2000 connector to rectify the issue, and you're going to learn how to do it.
No big deal for me, work is work. The wire pull is torturous, so I'm going to use a Molex field replaceable NMEA 2000 connector to rectify the issue, and you're going to learn how to do it.
The bag has four parts, and assembly is straight forward, if you know the tricks to make it work. What isn't so clear are the included instructions, in particular the line that reads, "secure conductors to the appropriate conductors as shown." Well it's not shown for starters, and the how is somewhat elusive. Another case of inscrutable "Height of Brevity" technical documentation.
Let's start with the basics, and I will translate. Put all of the parts you can't put on the wire after the connector is installed on first in the right order. This saves you some interesting language when you stare at the left over parts. It's also good they tell you the black knurled ring thingy must be rotated clockwise to install. I don't know if I could have figured this out all by myself. I think it's one of those righty tighty lefty loosey sort of things.
This is what you end up with. Since the wire is hanging down, if I let go, gravity will kick in and the parts will fall off. So you need something to thwart gravity's insistent pull. A wad of tape, a tie wrap, or in my case not shown a pair of long jawed hemostats clamped on the wire. I use these to extract pull wires out of small holes, and before you ask, no the ends aren't burnt.
Step one, strip the outer case of the cable, and remove all of the blue plastic wrap stuff. You want to end up with about an inch and a half of wires exposed. Take the blue wire and clip it short leaving it about three quarters of an inch long.
Good, now strip the blue wire's sheath back no more that one quarter inch. Did I mention the small jewelers screw driver? No? Well you will need one so go get it. Attach the blue wire to the blue post. You don't want a lot of wire hanging out in space afterward.
Now pick a wire, any wire, and hold it on the connector as I did in the picture. Cut the wire where the red arrow is pointing. Now gather the remaining wires together and cut them to this new length.
It gets a little tricky here so listen up. The reason we cut the wires is they are now about the right length when installed. Strip them back about three eights of an inch, and twist the ends tightly.
The bare shield wire must also be twisted tightly. Here is the part of the design I don't like. The blue post is exposed, and the shield wire is bare. I never want the twain to meet. I have two choices here. The first is to take a piece of tiny shrink wrap I don't have, and don't shrink it on the bare wire.
The second option is to take a piece of electrical tape, and cut a piece about a fat quarter inch wide, by three quarters of an inch high. Take this and fold it in half around the bare wire, up a bit, and leave it for the time being. Now things are easy. Carefully insert each wire into the correctly colored hole and tighten. The one with no paint is the black wire, and the gray painted one is the shield. When you're done take the piece of magic black tape and slide it down to the bottom protecting the bare wire from contacting the blue post.
Now just screw the parts together. If they don't screw on, try twisting them in the other direction. One or the other will work even if you're caggy handed. The black knurled piece doesn't screw all the way down, at least by hand, and I'm not going to try to force it.
It's a wonky design for a connector. You end up with the bare wire able to make inappropriate contact with the blue post. I think the device net standard should be redesigned so the shield wire is the center pin soonest. This will make my life easier. We can call it "Device Net 3000." The cable manufacturers will love it. Kate sent the hand model out for a manicure, but found him at the watering hole instead.
Tuesday, 17 May 2016
NEMA oops I mean NMEA
Language is a wonderful and changeable thing. Acronyms, and our attempts to pronounce them can bring about decidedly weird effects, so today we are discussing the National Marine Electronics Association, or in its acronym form NMEA. This is not to be confused with NEMA, the National Electrical Manufacturers Association, the National Emergency Management Association, or even the New England Multihull Association.
Somehow over linguistic time, the acronym NMEA has ended up being universally pronounced, such as acronyms can ever be pronounced, as Nee ma. This verbal utterance has become so pervasive, that the marine populous, has actually changed the spelling of the acronym NMEA to NEMA to reflect how we actually say the acronym. If you search "NEMA 0183" -NMEA, Google finds over 24,000 references. I did some snipping off the web of examples, and noted that even the Installer himself has screwed this up at times, and boy I'm not alone. I have purposely not changed it as a personal reminder to myself.
The rate of change from NMEA, to NEMA has been increasing rapidly over time. There are a few references in the eighties, even more in the nineties, and in this decade using NEMA in place of NMEA is almost common place.
So there are are three options available, do nothing, and continue to pronounce NMEA as Knee ma, change the name of the National Marine Electronics Association to the National Electronics Marine Association, or change the way we pronounce it to "NA Me Ah. My vote is to be diligent about spelling it correctly, and to continue to pronounce it Knee ma, or Knee maw if you live in the south. Tomato, tomahto, potato, potahto. Nmea, (it is a word, sort of) that is a cool electronics network on your boat bro.
By the way this was all triggered by attending the NMEA conference on Sanibel Island (almost). I am just about done with the piece.
The photo above was taken by Canadian Phil Boisse.
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