SC-30 wiring

[robjl]

I have just purchased a used SC-30 with a IFNMEASC. I'm new to NMEA so please excuse my lack of knowledge. The other nav gear on the boat is two NNVX2 ,with radar and DFF1, and a RD30
Can I create a N2K backbone in parallel on the SC30 connection in the IFNMEASC to feed a FI-504 multi, (I"m mostly interested in pitch and roll)?
Or can I add the SC30 to a WS-200 that currently is connected to a FI-501.

 

[Johnny Electron]

Can I create a N2K backbone in parallel on the SC30 connection in the IFNMEASC

No, you can not. The IF-NMEASC box basically turned the NMEA 2000 SC30 into a 0183/AD-10 SC30 device. The bus between the IF-NMEASC and the SC30 is proprietary at this point and can NOT be connected to NMEA 2000. If someone needs 2000, the way to do it would be to take one of the 0183 ports of the IF-NMEASC to a 0183 to 2000 converter (like the Furuno IF-NMEA2k2)

 

[robjl]

Thanks for the quick reply,
I was basing my ideas on the diagram I found online, file attached below.
Alternately, can I put a N2K plug on the SC-30 (leave the IFNMEASC out) and create a circuit/backbone & Ts for the FI501,FI504, WS-200 and a RD33?
If I can just add a plug how is it wired?
Or do I need a junction box like the FI-5002?
The existing SC-30 lead (without plug) has a 120 Ohm resistor in it.

 

[Johnny Electron]

If that came from a FurunoUSA website; please provide the link because that is a very early document and WRONG. It should be taken down from wherever it is. You can not wire into that bus with NMEA 2000.

 

[robjl]

I found it here:
https://www.google.com.au/search?q=furu ... apRMe2gbsM
NOT a Furuno site.

 

[robjl]

Can you direct me to a wiring diagram for a N2K plug on the SC-30.
The unit I have was wired direct to the interface so has no plug, it does however have a termination resistor in it which I find strange, does it need the built in (the wire) termination resistor if it is wired direct to the IFNMEASC?
I can't find wiring pins/colours for a N2K plug in the manual.

 

[Johnny Electron]

When the IF-NMEASC is used with the SC30 it is a canbus but NOT NMEA 2000. The IF-NMEA2k2 provides the needed power for the bus and SC30. Termination like NMEA 2000 is done with two terminators. One is built into the IF-NMEASC processor and the other is either added by the installer or the installer uses the optional backbone cable for the SC30 that has a built in terminator in the cable connector of the optional cable. This bus is proprietary and nothing besides the interface and SC30 can be there. At this point you have 0183 and AD10 ports available on the IF-NMEASC. There are no NMEA 2000 ports. If you wish to have NMEA 2000 data, you take one of the 0183 ports and connect a 0183 to 2000 converter like the IF-NMEA2k2 data converter. This converter takes the IF-NMEASC 0183 data and converts it to NMEA 2000 that can be connected to an existing NMEA 2000 bus.

 

[robjl]

Yes I understand that.
But can I use the SC-30 in a NMEA 2000 circuit with the cable I have.
The cable I have from the SC-30 is 8 wires,(shield/red/black/blue/white/green/yellow/purple and it has a 120 Ohm resistor between the blue and white wires)
If I want to use the SC-30 as a N2K device only do I just use the shield/red/black/blue/white into the end (not the branch) of a N2K T on a backbone?
Can I use a backbone with Ts or do I need a Junction box as shown in the diagram in the SC-30 Brochure here:
https://furunousa.com/-/media/sites/fur ... ochure.pdf
Thanks again for great support.

 

[Johnny Electron]

If you entirely remove the IF-NMEA2k2, you can go back to the SC30 being a NMEA 2000 only device but it would require that the correct cable be used. It must be on without any terminations in place including internal and it must be 6 meter or less in length to meet NMEA 2000 standards. I have no magic wand to tell you what cable the original installer used but if the backbone cable designed for the IF-NMEA2k2; you will have real problems removing the built in termination.

 

[robjl]

Thanks Johnny, I've been using the "Furuno CAN bus Network Design Guide" forgive my ignorance, I'm on a steep learning curve..

https://www.furunousa.com/-/media/sites ... design.pdf

On page 8-9 it shows diagrams that suggest the devices with internal terminators like SC-30/WS-200/FI50/GP-330B can be linked at the ends of a backbone (not branches) as in Fig.24.
I have the cable MJ-A10SPF0015.. as suggested page 9 (d) SC-30 ..
I just need to splice a cable end, I have a spare drop cable N2K pigtail, I'll just connect the 1-5 (NMEA 2000) wires as you suggest but it seems from the "CAN bus design guide" that the termination resistor that you say is "NOT allowed" is OK.
What am I missing?

 

[Johnny Electron]

The SC-30 has no internal termination. That is not true. Out of the box the SC30 has no external termination in the cable either. It comes with a standard NMEA 2000 drop cable. I think you are getting confused by the existing setup you have, which is using the IF-NMEASC and has established termination someplace to accommodate the needed Canbus structure for the addition of that interface. I don't know what cable was used by the original installer of your IF-NMEASC. What I am saying is that you need to follow NMEA 2000 architectural rules when you remove the interface and go back to the SC-30 connecting to the NMEA 2000 bus. If you end up with too many terminations because you overlook one built into the cable then everything will be a mess.