How to feed old Smartcraft gauges from a modern Garmin GPS
07-28-2024 | 11:14 AM
#11
Registered
Joined: Jul 2023
Posts: 3
Likes: 0
I’ve had no luck with this setup.
I have an optimax 75 (upgraded to 115) running a smartcraft cable from the outboard (terminator in cable on outbord end) to a 4 port junction box at the helm, terminator in one of the ports and the other two ports connected to system tach and system speed. When connecting the can bus cable to the junction box, the terminator is removed. System tach still works no problem. The can bus cable is connected to a 4-port nmea2000 T-connector which also has 12 volt and the dropper cable from the garmin 720s connected. Have tried with terminator installed in the last end of the T and without. On the 720s I have both serial ports set to standard and nmea bridging is on. Have tried various nmea sentences on and off. On the smartcraft gps sensor installed and use gps speed is ”yes”. No speed ndicated on the speedo, neither digital or analogue.
I have an optimax 75 (upgraded to 115) running a smartcraft cable from the outboard (terminator in cable on outbord end) to a 4 port junction box at the helm, terminator in one of the ports and the other two ports connected to system tach and system speed. When connecting the can bus cable to the junction box, the terminator is removed. System tach still works no problem. The can bus cable is connected to a 4-port nmea2000 T-connector which also has 12 volt and the dropper cable from the garmin 720s connected. Have tried with terminator installed in the last end of the T and without. On the 720s I have both serial ports set to standard and nmea bridging is on. Have tried various nmea sentences on and off. On the smartcraft gps sensor installed and use gps speed is ”yes”. No speed ndicated on the speedo, neither digital or analogue.
09-12-2024 | 09:34 AM
#13
Thread Starter
Registered
Joined: Jan 2021
Posts: 925
Likes: 431
From: Gothenburg, Sweden
I was wrong about the Garmin 720 in the posts above. The Garmin 720 is not new enough to "bridge" speed over NMEA 2000. The newer Garmin models that do bridge, and which should work with SmartCraft with the Mercury cable, are on this list:
Garmin NMEA 2000 bridge capabilities by model
(Longer explanation of how I got this wrong, which might be useful to someone: There is a Garmin 720s with an external antenna and a Garmin 720 with no external antenna in the boat, connected to an NMEA 2000 bus. I was under the mistaken impression that the 720 gets GPS data from the 720s over NMEA 2000. Turns out that, oddly enough, the 720 and 720s can neither read, nor post GPS speed and position data over NMEA 2000. The 720 must be using an inbuilt antenna. The speed information on the NMEA 2000 bus comes only from a Lowrance GPS receiver that also connects to the NMEA 2000 bus. SmartCraft is using that information with the Mercury cable described above. These 3 separate GPS receivers show consistent speed, btw)
Garmin NMEA 2000 bridge capabilities by model
(Longer explanation of how I got this wrong, which might be useful to someone: There is a Garmin 720s with an external antenna and a Garmin 720 with no external antenna in the boat, connected to an NMEA 2000 bus. I was under the mistaken impression that the 720 gets GPS data from the 720s over NMEA 2000. Turns out that, oddly enough, the 720 and 720s can neither read, nor post GPS speed and position data over NMEA 2000. The 720 must be using an inbuilt antenna. The speed information on the NMEA 2000 bus comes only from a Lowrance GPS receiver that also connects to the NMEA 2000 bus. SmartCraft is using that information with the Mercury cable described above. These 3 separate GPS receivers show consistent speed, btw)
