T&T: nmea expanders

[Peter Bennett]

Thursday, January 1, 2009, 12:48:40 PM, Larry wrote:

LNB> If I understand right, the three nmea listeners should be no problem and the
LNB> only potentiol problem would be the laptop.

Correct

LNB> It works fine with the chart
LNB> plotter output. You had sent me this wiring diagram several years ago and I
LNB> had it in my autopilot file. Looks  like in one switch position, you have
LNB> the laptop and the Raymarine in parallel, fed by whichever Garmin you have
LNB> selected.

Yes, S1 selects which GPS is used.  Somewhere I have a later drawing
showing a Ray54 DSC radio connected in parallel with the PC.

Switch S2 selects either the selected GPS or the PC to feed the
autopilot.  This allowed me to use either the PC (in the cabin) or
either bridge or cabin GPS to feed the autopilot.

LNB> Don't think I can smoke anything by trying Worst case scenario is something
LNB> won't work.

LNB> Regards.

LNB> Larry


LNB> --------------------------------------------------
LNB> From: "Peter Bennett" <peterbb4 at interchange.ubc.ca>
LNB> Sent: Thursday, January 01, 2009 12:48 PM
LNB> To: "Larry N. Brown" <cigano55 at hotmail.com>
LNB> Subject: Re: T&T: nmea expanders

>>
>> NMEA-0183 signal voltages should switch between 0 and +5 volts.
>>
>> Officially, a PC serial port should want -3 to -15 volts for one
>> state, and +3 to +15 volts for the other.  In practice,  almost all
>> serial ports will recognize 0 volts as a low level - they don't need
>> the negative voltage.  (I do recall, long ago, hearing that some NEC
>> notebooks wouldn't work with NMEA-0183, put haven't heard of any
>> problems recently)
>>
>> If you look at my drawing "Simpler NMEA-0183 Wiring from a previous
>> boat" at http://members.shaw.ca/peterbb/ , you'll see that I had NMEA
>> data going directly into the PC, without a multiplexer or expander.
>>
>> I do have a multiplexer on the present boat, because I need to combine
>> signals from three NMEA sources.
>>
>> Thursday, January 1, 2009, 10:21:01 AM, Larry wrote:
>>
>> LNB> Peter,
>>
>> LNB> Not to flog a dead horse but I reread your email and I don't see as I 
>> need
>> LNB> that Noland expander. Is the signal voltage on the laptop the same as 
>> the
>> LNB> other listeners? I have 3 listeners in addition to my laptop. If the 
>> all
>> LNB> operate at the same voltage it seems they can be paralleled up on a 
>> terminal
>> LNB> strip. Is the opto-isolation necessary?
>>
>> LNB> Regards.
>>
>> LNB> Larry
>>
>>
>> LNB> --------------------------------------------------
>> LNB> From: "Peter Bennett" <peterbb4 at interchange.ubc.ca>
>> LNB> Sent: Tuesday, December 30, 2008 1:48 PM
>> LNB> To: "Larry N. Brown" <cigano55 at hotmail.com>;
>> LNB> <trawlers-and-trawlering at lists.samurai.com>
>> LNB> Subject: Re: T&T: nmea expanders
>>
>>>>
>>>>
>>>> Tuesday, December 30, 2008, 10:59:21 AM, Larry wrote:
>>>>
>>>> LNB> OK. So with the help of a couple listees and the Furuno techies I
>>>> think I know
>>>> LNB> what I'm doing. I've hooked my Furuno chartplotter to my computer
>>>> with their
>>>> LNB> proprietary cable which ends in a d-232 plug. Great. Now I can
>>>> upload--by way
>>>> LNB> of Robin Hood's barn-- my capn routes to the chart plotter. Now, as 
>>>> I
>>>> get a
>>>> LNB> little deeper into this thing, I'd like to figure out some 
>>>> solutions
>>>> to other
>>>> LNB> tasks I want done.
>>>>
>>>> LNB> 1) send nmea data to autopilot
>>>> LNB> 2)send nmea data to Floscan meters
>>>> LNB> 3)send nmea data to DSC on radio
>>>> LNB> 4) send chart plotter gps data to laptop as a back up for the deluo
>>>> gps I'm
>>>> LNB> now using. I'll run the capn on the deluo gps and the chartplotter 
>>>> on
>>>> the
>>>> LNB> Furuno gps.
>>>>
>>>> There are a couple of NMEA-0183 system drawings on my site at
>>>> http://members.shaw.ca/peterbb/
>>>>
>>>> One NMEA-0183 output should be able to feed at least 4 inputs, so you
>>>> may not need a multiplexer or expander. Multiplexers are required if
>>>> you need to combine NMEA data from two or more sources.
>>>>
>>>> You will want a switch to select between the two GPS receivers for the
>>>> PC input.  You may also want one to select either PC or plotter out to
>>>> the autopilot.
>>>>
>>>>
>>>> -- 
>>>> Peter Bennett, VE7CEI    Vancouver, B.C., Canada
>>>> Ennos 31 "Honeycomb"
>>>> GPS and NMEA info: http://vancouver-webpages.com/peter
>>>> Vancouver Power Squadron: http://vancouver.powersquadron.ca
>>>>
>>>>
>>
>>
>>
>> -- 
>> Peter Bennett, VE7CEI    Vancouver, B.C., Canada
>> Ennos 31 "Honeycomb"
>> GPS and NMEA info: http://vancouver-webpages.com/peter
>> Vancouver Power Squadron: http://vancouver.powersquadron.ca
>>
>> 



-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca