Getting Furuno GPS working with Navman auto

[plee]

I hope this helps someone get their Navman autopilot (3100) working with their Furuno GPS (GP32) and acting as a true autopilot in route GPS mode so that they can sail a route of multiple waypoints - as it should - but cant. Firstly the instruments talk to each other and work fine in com and single waypoint GPS mode. They can not communicate in GPS route mode with multiwaypoints.
Here is the fix... firstly... you need a mux (multiplexer) I used the Brookhouse mux. Then you need to program it to remove the aam sentence (arrival Alarm) .. then remove the vericle arrival point alarm (apb sentence) ... then you need to mute the GPS from sending NMEA to the autopilot for 7 seconds. Brookhouse Mutiplexers NZ can help you with all this. Marvellous bloke... and now its simple to do
Here is the why... at ärrival at the first waypoint either of the arrival alarms in the NMEA code the GPS sends out, an alarm (no you cant stop the GPS doing on the instrument) which acticates ënd of route"in the Navman. OK.. so we write a little program to cut out the alarms ... when we try it like this ...now the navman wants to turn back to the waypoint just passed... gggrrr...why... because the Furuno continues to issue NMEA sentences for the last waypoint just passed for 6 seconds AFTER it has passed it.. why, who knows or cares. By muting the apb sentence for 7 seconds after each waypoint is reached the boat will sail to the waypoint in the route... go through it in a straightline for 7 seconds... then turn onto the course for the next waypoint as instructed by the new NMEA sentences from the GPS ... and so on. It has taken me and Brookhose a while to sort this out... but now it is wonderful. Works perfectly... a great autopilot and a very reliable GPS Wouldnt swap them now - ever. Good on ya Wout Brookhouse