Older Simrad AC20 and new GPS

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wkearney99

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Feb 17, 2018
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USA
Vessel Name
Solstice
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Grand Banks 47 Eastbay FB
I've got a boat that's had a bunch of stuff set up on it over the years and some of it is obsolete.

Before I go down a particular path I have to ask, does anyone know of reasons why a Simrad AC20 autopilot would have any issues with changing to any one brand/model of NMEA2K-0183 bridge vs any other?

Currently mine gets 0183 data through some Furuno MFD12 chart plotters. GPS->MFD->Ethernet->MFD->-0183->AC20. Likewise heading data is coming in via NMEA2k->MFD-Ethernet->MFD->0183. I'm likely replacing the GPS unit as I've had intermittent issues with losing position.

I've learned over the years to never assume something 'ought to work' just because of specs. I've also learned it's often better to know what DOESN'T work than anything else.

I'm also prepping the networks for the eventual upgrade of the chart plotters. I'm getting as much as possible onto the NMEA2k bus and away from being exchanged through the plotters. A lot of which I've already consolidated into one MFD instead of three different ones it had been using before. That and discovering stupid stuff like a bus being powered off much smaller gauge wire than could support it.

So anyone out there handled upgrading their GPS and heading gear while still using an older AC20 Simrad with AP26 remotes?
 
Get a SimNet/N2K adapter cable, 24005729, put it on the bus, and carry on. It would simplify what you have now. Turn your data sources on, activate a route or waypoint on the connected navigation device and run the Automatic Interface Setup on the AP and you should be done. If you have 0183 devices you want to keep, the NEMO Gateway from Rose Point works well and has 4 0183 inputs. It does need to be connected to WiFi to set it up and look at the data via an app on a device, and a cheap ethernet/wifi travel adapter will do the trick. To the original question, any device output meeting the 0183 spec and providing the required sentence will work.

Note the NEMO converts AIS data from N2K to 0183 but not vice versa.
 
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I have pins on the AC20 labeled Robnet going to the blue sockets on the back of the AP26 remotes. There's nothing into the yellow sockets on the AP26's.

From the Simrad setup PDF it appears an AP26 can have both blue Robnet and yellow Simnet connections into it simultaneously. But there's no Simnet input into the AC20 autopilot computer. I'm fine with continuing to use the blue Robnet connections to the AP26 remotes. Unless there's some other compelling reason to use Simnet for their communication? Or other N2K benefit?

I have GPS being provided via 0138 through a chartplotter. (GP320B->MFD12->0183). There's also an H2183 via MFD and a PG-700 via N2K (which seems partially redundant... but whatever that's another thread).

I don't need to eliminate the 0183 into the AC20 computer from the MFD12 as I'm not likely to be running autopilot without the plotter. At least not any time soon, as I don't plan on using anything else (PC, OpenCPN, etc) for navigation anytime soon. Not that there's anything wrong with that idea, just that I don't have that on my current 'to do' list.

It looks like I'd need to use something else to get the 0183 data in/out of the AC20.

The Simrad AT10 supposedly handles Simnet to/from 0183. But then I'd need to set up a Simnet network, as it would need power. I'm unclear if an AT10 could be powered off an N2k network using just the 24005729 adapter cable. I also get the impression that the AT10 is a tee device, not an endpoint. So I'd need to have it at the end of the N2K network... which is NOT where the AC20 computer is located.

So what, if any, benefits would I gain having the AP26 control units connected to the N2K network?
 

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Looks like I should probably consider a multi in/out 0183 box. I've got enough stuff still talking/listening on 0183 that a bridge would likely be a useful solution.
 
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