FAP7002 / 711c CAN Bus Power Question

[seaveepete]

I installed my 711c AP a few years ago and recently wanted to extend my N2K network and combine it with a separate network that has engine and fuel tank info. While examining my setup I realized that I do NOT have a power tap on the backbone. Further investigation and some wire tracing led me to discover that I did run 12v power to the TB12 CAN Bus connection block. Note also that the FAP7002 is wired to the network backbone using the TB11 connector with a drop cable and I did NOT use the terminating resistor.
First, let me say that everything has been working fine for a few years with the heading sensor and the entire 711c system plus my TZT2 units. I just wanted to confirm my understanding here that by connecting 12v to the TB12 connector I've basically COMBINED the FAP7002 data AND 12v network power on the one N2K drop cable.
Is this installation correct?

 

[Johnny Electron]

Every CANbus needs power and proper termination. Sometimes CANbus can be forgiving until it isn't. In your case, yes powering TB12 allows both power and CANbus (NMEA 2000) data communications to come out TB11. The power, when using that configuration, is limited to 1 amp. As long as your network design falls within that, it is okay. You should also check your bus for two termination points. For a simple setup, some would use the PG700 termination button as one of them and the included termination resistor for the other (typically put between the blue and white wires at TB11)

 

[seaveepete]

Thanks Johnny. I've been trying to connect my "Furuno" N2K bus to my "Suzuki" bus using a power isolator between the two backbones. Everything is terminated properly and working ok when separated but I've had issues on the Suzuki side when I try to combine the networks so I've just been trying to sanity check everything. I also do have a 1A fuse on the power supply to the CAN Bus terminals on the FAP7002.
Regarding the 1A limit on bus powered by the FAP7002... I don't know the current draw on each of the bus members there but can you confirm that I should be OK with just the following 4 devices on my Furuno bus?
- FAP7002
- PG700
- 2x TZTL12F

 

[Johnny Electron]

Yes, you are within power limits. Be careful about the Suzuki bus. If it truly is a Suzuki bus it probably shouldn't be directly joined to your NMEA 2000 bus. Normally there should be a "Gateway" used to bring over the Suzuki engine information to the NMEA 2000 bus. We had at least one case here on the forum where a customer tied a Yamaha bus direct without a gateway and it was ugly until corrected.

 

[seaveepete]

"Suzuki bus" was a poor choice of words - it's just how I describe the NMEA 2000 bus that has all of my Suzuki outboard related devices connected to it. That includes the engines, the C10 gauges, a separate N2K GPS antenna, fuel tank sensors, etc.