NMEA Stuff

[boatmike]

As I got such a brilliant response regarding compasses (thanks all on scuttlebutt!) I thought I would ask the following techie question for all the PBO electroheads out there.
Can one NMEA "sender" be wired to two or more NMEA recievers? In other words, if my Simrad Autopilot won't output NMEA at any more than 5Hz but I couple a 10Hz compass to it (which I think I can) and also couple the compass to a Radar that needs 10Hz directly rather than through the autopilot, will it work? Currently my old Cetrek GPS instrument and chartplotter recieve GPS that way so why not compass?

 

[FullCircle]

Yes, your system will work that way.
I have an ST4000 connected to the heading compass, the Navman Wind input and also to the JRC Radar Chartplotter and it takes the sentences it can read.
If you have a problem, then fit a multiplexer. Be careful which one you choose, as they vary a lot in price and ultimate configuration.

Here is an example, available from JGtech

NDC-2 The Actisense™ NMEA Data Combiner / Multiplexer allows connection of up to four NMEA (National Marine Electronics Association) inputs to be multiplexed / combined in to one NMEA output. IP66 case

* 4 NMEA 0183 data inputs, NMEA and RS232 outputs
* NMEA 2000 port converts from NMEA 0183
* Configurable Inclusion List & Port Baud rates
* Fully future proof with flash upgradable
* Raymarine approved.

I dont think you will need one for your application (they are all over 100 quid) but they will then allow a much wider range of inputs and outputs if you want to expand your capability.

 

[Oldhand]

[ QUOTE ]
As I got such a brilliant response regarding compasses (thanks all on scuttlebutt!) I thought I would ask the following techie question for all the PBO electroheads out there.
Can one NMEA "sender" be wired to two or more NMEA recievers? In other words, if my Simrad Autopilot won't output NMEA at any more than 5Hz but I couple a 10Hz compass to it (which I think I can) and also couple the compass to a Radar that needs 10Hz directly rather than through the autopilot, will it work? Currently my old Cetrek GPS instrument and chartplotter recieve GPS that way so why not compass?

[/ QUOTE ]

Depends on your compass type. If you have a Simrad J300X or J3000X autopilot junction box then your Simrad compass does not output NMEA directly, don't be confused with other makers' units. The conversion from Sin/Cos output to NMEA is done in the junction box, thus the NMEA heading output rate is determined by the junction box. If you have a J300X junction box with 5Hz heading output then there is a Simrad software upgrade to give 10Hz output. This upgrade can be actioned by a Simrad dealer or directly with Simrad but is only worth doing if you upgrade to the rate enhanced RC25 compass unit. So go to your nearest dealer and ask him to supply an RC25 to include software upgrade of your J300X.