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MARPA and SHS
06-03-16, 09:45 AM (This post was last modified: 06-03-16 01:53 PM by Chuck - Raymarine - Moderator.)
Post: #1
MARPA and SHS
I’ve got a legacy installation consisting of two E80 displays, Raymarine GPS and radar, an S2 AP Course Computer, fluxgate compass, and an 8002 AP control head.

The fluxgate is connected to the AP Course Computer, and the AP Course Computer to the 8002 via Seatalk, and then via Seatalk to an E80. The E80s are connected via Seatalk HS.

I bought and installed an external gyro (“Smart Heading System”) to improve the AP function. The only currently connected output from the SHS is a 2-wire connection to the Rate Gyro port on the AP Course Computer. The fluxgate remains connected to the AP Course Computer, not the SHS.

As expected this allows the AP to AutoLearn. AP performance is somewhat improved.

A second benefit I hoped for was improved MARPA performance. Is this single SHS->AP connection adequate to gain that? In rereading the manual I see mention of additionally connecting the SHS to an E80 via NMEA. I have not done that. What is the benefit of that connection--to get improved MARPA performance? Can the connection be to either E80 or must it be the E80 connected to the radar?

If NMEA will improve MARPA, how significant will that be? Both E80 NMEA ports are already used (depth sounder and AIS), so I’d need to invest in a mux to connect the SHS. Will the MARPA improvement justify that expenditure?

Thanks.
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06-03-16, 02:04 PM
Post: #2
RE: MARPA and SHS
Welcome to the Raymarine Forum danderer,

Q1. A second benefit I hoped for was improved MARPA performance. Is this single SHS->AP connection adequate to gain that?
A1. Yes

Q2. In rereading the manual I see mention of additionally connecting the SHS to an E80 via NMEA. I have not done that. What is the benefit of that connection--to get improved MARPA performance?
A2. The NMEA 0183 output of the SHS would only be interfaced to the NMEA 0183 input port of an E-Series Classic MFD when a SHS compatible autopilot course computer has not been interfaced to the system. In the case of the latter, a fluxgate would need to be interfaced to the autopilot course computer.

Q3. Can the connection be to either E80 or must it be the E80 connected to the radar?
A3. All data except for NTSC/PAL video inputs are share between E-Series Classic MFDs via Ethernet (SeaTalkhs). As such, the NMEA 0183 heading data source may be interfaced to either MFD. Their would be no performance advantage to interfacing the heading data source directly to the MFD which is primarily functioning as a radar display.

Q4. If NMEA will improve MARPA, how significant will that be? Both E80 NMEA ports are already used (depth sounder and AIS), so I’d need to invest in a mux to connect the SHS. Will the MARPA improvement justify that expenditure?
A4. These questions are moot per the responses provided above.
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06-04-16, 02:08 PM
Post: #3
RE: MARPA and SHS
Thanks very much for the detailed reply. Very helpful, but unfortunately I also remain a bit confused on your answer A2:

I read you response as saying: All you need to do is to connect the SHS to the S2 is to connect 2 wires from the RATE OUTPUT to the RATE GYRO input. (Plus power, of course.) This will allow the AP to do AST and the E80 generate better MARPA solutions.

However, looking at Appendix A of the SHS Owner's Handbook (81198-2, Feb 2005) in Appendix A, Figure A-3 shows a setup very similar to mine (course computer and MFD). That drawing shows not only the 2-wire connection but also:

* The SHS is connected to SeaTalk, and
* NMEA data is sent from the course computer to the MFD.

The text in that appendix is unclear on the reason for the SeaTalk connection shown (just for power?). It does talk about S1, S2, and S3 course computers and the NMEA connection, and says specifically under "Connecting to autopilot and Raymarine displays(s)":

"Connect the course computer NMEA 1 outputs to the NMEA inputs on the display".

I don't have either the SeaTalk or NMEA connections in-place.

So because the manual is unclear, but seems to contradict the info here, I'll ask again to double-check:

What is the set of connections I need to the SHS to maximize its functionality?
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06-06-16, 10:12 AM (This post was last modified: 06-06-16 10:13 AM by Chuck - Raymarine - Moderator.)
Post: #4
RE: MARPA and SHS
danderer,

The information provided within my prior response is correct and should be followed. In systems featuring a S1/S2/S3 autopilot course computer, the SHS should be interfaced to the course computer's Rate Gyro input and to the SeaTalk bus. When interfacing the SHS to a powered SeaTalk bus, only the SHS's yellow (data) and silver (shield) SeaTalk terminals will be used. The MFD will receive 10Hz gyro stabilized heading data via the autopilot course computer's NMEA 0183 Port 1 OUT terminals.
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06-08-16, 12:08 PM
Post: #5
RE: MARPA and SHS
Ah, looks like I made a big mistake in my original question. Sorry.

I asked about:

"...connecting the >>SHS<< to an E80 via NMEA."

Your answer to that is clear--it is not needed.

What I meant to ask was:

"...connecting the >>AP Course Computer (S2)<< to an E80 via NMEA."

My understanding from your last response is that I DO want to this to get the 10Hz heading data to the E80 for MARPA. That is consistent with the manual as well.

Thanks.
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06-08-16, 12:46 PM
Post: #6
RE: MARPA and SHS
danderer,

Q. My understanding from your last response is that I DO want to this to get the 10Hz heading data to the E80 for MARPA. That is consistent with the manual as well.
A. Correct.

You're welcome.
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