Wiring details to connect Navpilot 500 to sat compass SCX20

donpjr

Member
I want to confirm the wiring details to connect my SCX20 to my Navpilot 500 autopilots, replacing the current PG500 heading sensors. Can you confirm or correct the following: Most of below is from a post I found re: connection to SC30 so I'm basically confirming the same applies to the SCX20.

1. Install IFNMEA2k2. Cut the orange wire to get 38,400 baud functionality.
2. Tie back unused wires so they don't touch each other.
3. Connect IFNMEA2k2 to NMEA 2000 bus once to activate the 38,400 connection.
4. Connect yellow wire from IFNMEA to TB8-1 in AP processor.
5. Connect green wire to TB8-2.
6. No other wire connections required? No bare wire connection?
7. Set processor to other and select 38,400 baud.

I have two autopilots, only one is ever turned on at any time. I assume i can run NMEA 0183 wires from the IFNMEA2k2 to a terminal block and split off to TB8-1 and TB8-2 on each of the two autopilots and whichever one is operating will see the SCX20 compass?

I would appreciate confirmation of above, or any corrections needed, and any other tips to get this installation working. Thanks.
 
It seems you have done some studying and normally I would say "absolutely" but sorry I can't do that. We have had many customers use the SCX21 to the 500 series and be up and running in seconds. Because of the conversion being done from 2000 to 0183 (from SCX20) your plan causes an issue for the pilot. The old pilot heading port doesn't like to see any NMEA data other than the basic heading it expects. The IF-NMEA2k2 will be sending some additional sentence data that will cause the pilot errors which you can not stop. While your plan would still work, if using a customized converter that only puts out basic heading data to the port. I have seen it done using an actisense converter. The IF-NMEA2k2 while more flexible in some respects, it will not let you customize the sentence output.
 
Thanks Johnny. Better to know this now than after installing. Glad I asked. If I understand correctly the solution could be to use the Actisense converter instead of the IFNEMA2k2?

I was working from this prior 6/21 info which is apparently not valid now based on experience:
The right way to do it would be to get another IF-NMEA2k2 installed on the 2000 bus and set it to high-speed heading mode. I would remove the older PG500 and wire the 0183 data from the converter where the PG500 was and change the baud rate appropriately. This will provide the pilot very fast and high quality heading. You will need to change the heading source under "Sea Trial" to "OTHER" instead of PG500
 
Yes, if using the SCX20 then the solution would be to use and configure an actisense converter. We have done it and it works very well. You can not use the IF-NMEA2k2 in this particular application.

Normally I recommend the SCX21 for the Navpilot 500. If the old post discussed an option of using the IF-NMEA2k2, we have since discovered the pilot won't accept it.
 
Understood and thanks for the update. I am super happy with the SCX20 after using it for several months. The chartplotter and radar overlay are working great compared to the PG500 heading input. I will pursue the actisense solution for the AP to complete the system.
 
I now have the Actisense converter and preparing to configure it for Navpilot 500 operation. My plan is to set it to 38400 baud, and turn off all conversions on the Actisense except: Receive from NMEA2000 - PGN 127250 (Vessel Heading) and PGN 127258 (Magnetic Variation). According to the Actisense manual this will then send HDG and VHW signals to the Navpilot. VHW as far as I can see is not needed by the Navpilot but is sent with PGN127250. Is this sufficient information for the Navpilot to operate from the SCX20?

Next question is wiring to the Navpilot. I am assuming there isn't any information sending from the Navpilot to the NMEA200? If this is correct I only need to connect two wires from the Actisense converter to the Navpilot. The Actisense has two wires for sending data from NMEA 2000 to NMEA0183 device. A blue wire that connects to (B/-/GND) and a white wire that connects to (A/+/Rx). Which terminals on the AP Processor should I connect these two wires to?

Thanks, Don

Thanks,
Don
 
I don't think you want PGN 127258 (Magnetic Variation) turned ON through the converter (or VHW). MagVar is normally something that comes in from your GPS, not fluxgate heading compass. I think we only had HDG turned on from the converter for the pilot when we tested. The wiring would go into TB8 pins 3 (+) 4 (-) and 6 (Ground)
 
Just to close this loop, the Actisense converter has been installed with only heading from the SCX20 sent to the Navpilot. All other conversions were turned off. Basically the blue and white wires from the converter are tied to the blue and white of the existing PG500 cable. The autopilot is showing the correct heading information matching what the plotter shows.

In the spirit of using a single heading source on the boat, is it possible for me to get rid of the final PG500 heading sensor and send heading info from my SCX20 to the FA150 AIS? This AIS needs AD10 format heading and I don't see any reference to that in the converter manuals (either Furuno or Actisense). Or do I leave this on a PG500. Currently the heading on the AIS is about 11 degrees off from the sat compass.
 
You could go either way. You could relocate and calibrate the PG500 to get it matching closely to the SCX20, or you could remove it from the boat and use another NMEA converter to bring over 0183 heading and GPS to the FA150. If you use a converter, make sure to change the instance number so it doesn't conflict with the existing one. The FA150 doesn't have to have AD10, it can work off NMEA 0183 heading. Because of GPS rollover and other reasons, you will want to make sure your FA150 has been updated with newer software.
 
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