Heading data for FAR2117?

[Anonymous]

Hi,

I'm sketching out what it would take to install a FAR2117 in my boat, and I'm trying to sort out how to get proper heading info to the FAR. According to the FAR manuals and based on info I have read here, the FAR requires (and only accepts) HDT for True heading info.

I have two sources of heading, both on N2K, and the following questions:

1) One heading source is a Sat Compass (not Furuno) that emits PGN 127250 Vessel Heading @10hz, and provides a True heading. I'd like to confirm that the IF-NMEA will translate that to HDT @10hz

2) Assuming the IF-NMEA does translate per #1 above, is 10hz sufficient for the FAR? The FAR installation manual says 20hz is required.

3) My alternate heading source is a rate compass that also emits PGN 127250 Vessel Heading at 10hz, but it sends Magnetic heading, not True. After all, it has no idea where it is so doesn't know the local variation. However, I have another device that emits PGN 127258 Magnetic Variation. Will the IF-NMEA take both PGNs and produce HDT for the FAR? Other N2K devices do this and can operate in T or M mode even though the compass only emits M heading.

4) It doesn't look like the FAR accepts or requires any vessel pitch, roll, or heave info. Is that correct?

5) Does the IF-NMEA have any way to select which heading source to use? I have two sources for redundancy, and N2K supports that very nicely, however it requires some way to tell a device who it should be listening to. Am I correct that the IF-NMEA can't do that?

I'm sure I'll have more questions, but this will be a good start at helping me sort this out.

Thanks

 

[X-band]

Hello Twistedtree,

The FAR2117 will accepted HDT @ 10hz. You will want to use the IF-NMEA2K2 to provide the high speed true heading.

The IF-NEMA2K2 will not output HDT with only a magnetic heading plus the magnetic variation.

You are correct, the radar will not use pitch, roll or heave.

You cannot select a source on the IF-NMEA2k2.

Thanks!

 

[Anonymous]

The IF-NEMA2K2 will not output HDT with only a magnetic heading plus the magnetic variation.

Thanks for the reply. That's very helpful.

So a PG700 that outputs magnetic heading, and a GP33 that outputs the current magnetic variation cannot be used to provide true heading to a FAR radar?

Does that mean that the only heading sources supported are a Sat compass or a gyro?

Thanks in advance.

 

[X-band]

That is correct. The IF-NMEA2k2 will not add the magnetic variation to the magnetic heading to output a true heading.

The FAR2XX7 must have the HDT sentence or AD10 heading (like from a gyro converter).

 

[Anonymous]

Sorry for beating a potentially dead horse, but assuming a new build, it then sounds like the only heading sources that will work with the 2xx7 radars is an SC30 or and SC50? Correct?

 

[X-band]

That is correct. Note that when using the SC30, its recommended to use the optional IF-NMEASC, this will allow you to use AD10 heading to the radar.

We also have a new product coming out soon that would work as a true heading device called a GS100.

More info could be found here: http://www.furunousa.com/ProductDocumen ... ochure.pdf

 

[Anonymous]

Thanks. Whats the advantage of using AD10 into the radar as opposed to NMEA?

 

[Anonymous]

As I dig deeper into planning this installation, I have more questions. The installation and operators manuals are unclear on a few things with respect to the various data ports. Most of this boat is N2K and I'm trying to figure out how many converters I need, going in what direction, at what baud rates, and carrying what data to make this work.

1) I'm trying to confirm the port baud rates. According to the operators manual, the heading sensor input port is selectable for 4800 or 38.4k. Does it auto select, or is it controlled by some setting in the radar configuration?

2) The manuals list the sentences supported, but it's unclear whether certain sentences are only supported on certain ports, or if you can bring anything in on any port. So, for example, Could I bring all nav and heading sentences in on the log or navigator port, or will HDT only be recognized on the heading port, and other sentences only on the log and navigator ports? If certain sentences are only supported on certain ports, it would be great to have a table that ****** it out unambiguously.

3) Along the same lines, is the AIS port dedicated/restricted to AIS sentences, or can it accept and send other messages too?

Thanks

 

[X-band]

1) It is automatic as long as the radar is not in IMO mode (IMO requires heading @ 38400).

2) HDT needs to go into the heading port. The NAV and LOG port can take all GPS/ speed log information. You can select the source of the Nav info in the NAVAID menu, GPS1 is the NAV port, GPS2 is the LOG port.

3) The AIS port is dedicated to AIS only.

 

[Anonymous]

Thanks for the quick reply. That's hugely helpful.

Any plans to add an N2K interface on the FAR2xx7 family? It sure would simplify all this.

 

[X-band]

NMEA2K is not used on IMO vessels so I don't think it will happen.