Garmin 551 to Nasa AIS Engine - Connections ?

[Newman]

Being a new (secondhand) boat owner I would appreciate any help I can get on connecting a Nasa Marine AIS Engine 3 to a Garmin 551 Chartplotter. At this moment in time I just want to set up a temporary ‘stand alone’ arrangement, then once the boat is ‘home’ I will have more time to take a closer look at perhaps ‘linking in’ some of the existing equipment.

I hasten to add that with the above equipment I also purchased a suitable VHF aerial.

The Nasa AIS has two ‘coils’ of cable. One coil consists of a twin red cable, one having a black line and being the negative. The other has an in-line fuse, being the positive.

The other coil of cable has a black outer sheath with male and female data connections at the ends. There is also an external blue cable running the entire length of this cable and is terminated in the data connections.

Being that there is a female data connection on the AIS Engine I have cut off the female end of the cable which revealed the following internal cables:
Red, Black, and a Bare (unsheathed). Plus of course the external Blue cable.

The Garmin 551 Chartplotter wiring harness offers the following cables for connection, coloured and labelled as below.

Red: PWR Power 10-32 Vdc
Black: GND Ground (power and NMEA 0183)
White: CAN High CANet H (if applicable)
Green: CAN Low CANet L (if applicable)
Brown: P1RXD NMEA 0183 port 1 Rx (in)
Blue: P1TXD NMEA 0183 port 1 Tx (out)
Orange: Acc/ON Accessory on
Yellow: ALARM Alarm low
Grey: P2TXD NMEA 0183 port 2 Tx (out)
Violet: P2RXD NMEA 0183 port 2 Rx (in)

Can anyone advise as to which cables on the AIS are connected to which cables on the chart plotter. I would hate to damage either piece of equipment.

The most convenient source of supply on the boat, for my temporary stand-alone setup for this single homeward bound trip, is a cigarette lighter socket close to the chart table. Would this be ok ?

One final thing, Could I wire the 12v supply cables for both units in parallel to a ‘cigarette lighter plug’ and sit in the car at home “discovering” my new system and putting in some waypoints etc ?. Or perhaps I should try this without the AIS connected as we don’t get much shipping passing through the middle of Kent !.

Your comments and assistance will be most appreciated

 

[Playtime]

The power and ground wires for both units should be connected to 12V (+ and -ve respectively), either separately or in parallel, with appropriate fuses or circuit breakers in each circuit. This can be via a cigarette lighter plug for test purposes, if required.

For data, the AIS black wire should be connected to the 551 brown wire (Port 1 In) and the AIS screen should be connected to the 551 black wire (Power ground).

PS I've no idea what the blue wire is for. It might be worth double checking that the AIS black wire was connected to Pin 2 of the data plug you removed. Does the AIS Engine 3 Manual not identify the wires to use? The info I have given is for AIS Engine 2 but is probably correct for Engine 3.

 

[pvb]

PS I've no idea what the blue wire is for.

The blue wire is a 4800baud input for a GPS signal, which gets multiplexed with the AIS data and output at 38400baud.

 

[Elemental]

The blue wire is a 4800baud input for a GPS signal, which gets multiplexed with the AIS data and output at 38400baud.

...and is extremely useful for me because I feed that (the multiplexed output) into a splitter. One part goes to a serial->usb converter which is then plugged into my laptop providing GPS and AIS sentences to OpenCPN with CM93 charts. This works as a great chart table plotter and AIS system. The other half of the split feeds my binnacle mounted plotter at the helm (I can therefore use the plotter internal GPS or the external GPS at the wheel). Both displays therefore show GPS and AIS info.

 

[Joker]

I am going to attempt exactly the same task tomorrow. I'll let you know how I get on!

 

[Playtime]

...and is extremely useful for me because I feed that (the multiplexed output) into a splitter.

What sort of "splitter"?

A NMEA Talker can directly drive up to 4 Listeners; no special splitter is required - just wire.

 

[Elemental]

A NMEA Talker can directly drive up to 4 Listeners; no special splitter is required - just wire.

Exactly that. I just referred to it as a splitter as it's a screw connector in a box.

 

[VicMallows]

. One part goes to a serial->usb converter which is then plugged into my laptop providing GPS and AIS sentences to OpenCPN

Slight divergence:
I have a usb-serial converter which works fine for most AIS messages, but NOT for the longer messages which contain the static data such as the ships name. (everything OK if I use a serial port).

Any explanations?... or suggestions for a (cheap) usb-serial converter which DOES work properly with the NASA AIS.

Vic