NMEA Problem

Trying to interface my auto-pilot, NMEA 0180, with my Garmin chartplotter NMEA 0183. When energized, the auto-pilot goes nutso. The Garmin manual states under Interfacing: The following formats are supported for connection to external devices. NMEA 0180, 0182, and 0183. Where am I going wrong?

Which garmin say's it supports nmea 0180? If it does in fact output a nmea 0180 data sentence format, it would need to be selected in the nmea output setup. You must have a vintage autopilot to use 0180. That hasn't been a standard almost for 30 years!

NMEA18x is a serial communications protocol. Input from one device goes to output of the other. Then as already mentioned, the correct outputs and inputs have to be selected during device setup.

Ken

The Garmin manual has the NMEA Output Formats on page 81, but there are only 75 pages in the manual. I was able to change the baud rate on the Garmin from 2400 to 1200 bauds as required by the auto-pilot, but cannot find a way to change the NMEA output from NMEA 0183 to NMEA 0180, if that is even possible.

Call Garmin and see what they say.

This is an example why I always state "Keep it in the family"

Alaskan Sea-Duction said:

Call Garmin and see what they say.

This is an example why I always state "Keep it in the family"

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Will be calling Garmin on Tuesday.

What specific make/model# of chartplotter and autopilot computer? Might be helpful to search on those specific model numbers to glean insight from others that may have posted about them.

Where is your system getting it's heading and compass info? And rudder indication? All of those get included when the AP tries to make calculations and issue rudder-change instructions. I've had a slightly wonky rudder indicator on my Simrad setup. But I don't use the AP, so I haven't delved into resolving it (most likely it's just the rudder indicator sender failing).

The auto-pilot is a 34 year old Wagner, the chartplotter is a 19 year old Garmin 176C. The auto-pilot relies only on the fluxgate compass without GPS imput, it cannot compensate for set and drift. The auto-pilot control unit, is mounted at the lower helm, meaning a lot of stair climbing up and down from the flybridge to make constant course adjustments. Interfacing the control unit with the chartplotter would help alleviate the situation.

ancora said:

The auto-pilot is a 34 year old Wagner, the chartplotter is a 19 year old Garmin 176C. The auto-pilot relies only on the fluxgate compass without GPS imput, it cannot compensate for set and drift. The auto-pilot control unit, is mounted at the lower helm, meaning a lot of stair climbing up and down from the flybridge to make constant course adjustments. Interfacing the control unit with the chartplotter would help alleviate the situation.

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Autonav took over the Wagner AP, right? Might be worth asking them about your options as well. I'd think having a second station for AP control would be worth considering.

wkearney99 said:

Autonav took over the Wagner AP, right? Might be worth asking them about your options as well. I'd think having a second station for AP control would be worth considering.

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If I can't interface with the Garmin, I can always move the auto-pilot to the flybridge. I never use the lower helm for piloting.

ancora said:

If I can't interface with the Garmin, I can always move the auto-pilot to the flybridge. I never use the lower helm for piloting.

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I'm never one to suggest spending anyone else's money, but before you go that route, moving hardware and wiring around, it might be worth investigating what upgrades are possible.

Not necessarily to the "latest and greatest" but perhaps to an interim step. One somewhere between 34 years ago and now. Like maybe just a second-hand AP computer, one that had "less worse" NMEA integration and support for a second station. It'd at least be worth determining what can/can't be done, and at what price-points.

The cost of moving the control unit to the flybridge will be none, as I do all my own work. I am reluctant to pour money into buying a new system for something I have lived with for over twenty years.

I hear ya. But moving wires around often introduces new problems too. I'm just suggesting a little research into half-way upgrades might be enlightening. Find a used AP controller and second station and maybe get more cooperative NMEA integration in the process. Just an outside-the-box suggestion.

Called Garmin, was told the unit will work with the auto-pilot if I connect the data out wire from the Garmin to the auto-pilot control unit. Now all I have to do is find which wire out of twelve to connect the data out wire. Ain't we got fun?

Is this the complete manual you are looking for?.......

My manual has a few less pages being older. The Garmin is not the problem, it's the Wagner auto-pilot that was made before there was GPS. That manual mentions LORAN C connecting with the control unit. The LORAN C has an output data wire and a ground. I believe I have the correct data output wire connected to the proper wire going into the control unit. According to Garmin, I have to connect the data in wire to the control unit. The Wagner manual has all the schematics for the control unit and the pump set, so it's a matter of figuring out what wire to use going into the options port of the control unit.

I finally found the correct wires to tie into...and it worked. Tried it out yesterday on a fifteen mile long off-shore Predicted Log contest and came in last. I'm thinking it's me that needs more experience with the system. I'm going out again and try running a course inside the bay at a slower speed.