Will S3 Computer accept outside NMEA Heading?

[Wimpress]

Apparently a lightening strike got to my AIS (now back with Raymarine for repair) and my S3G Course Computer (dead SeaTalk and Rudder Reference inputs).

1) I have recently installed an Airmar Heading Sensor (with 3 axis gyros and accelerometers) to feed the E140 Wide MFD's.

2) I have access to an S3 (non-gyro) computer. I believe the manual says that it accepts HDG, HDM, and HDT sentences.

Question: Would the S3 work using the Fast Heading from the Heading Sensor?

I assume that I would not hook up the fluxgate compass.

What would be the best way to get the heading to the course computer? SeaTalk from the MFD? NMEA direct from the Heading Sensor? (I think it needs RMC to figure out Variation).

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Wimpress,

According to section 1.7 of the SmartPilot Series Commissioning Guide, these autopilots may be interfaced to a 4800 BAUD NMEA 0183 source of heading data. If using a 4800 BAUD NMEA 0183 source of heading data, it is recommended that the data source be gyro stabilized and that it have an update rate of 10Hz. Slower update rates will result in more sloppy autopilot performance.

The S1/S1G/S2/S2G/S3/S3G autopilot course computers will processes their signals in this order of priority:
1. Fluxgate compass
2. NMEA compass
3. SeaTalk compass

This means that if you want to use a NMEA compass as the primary compass, you need to disconnect the fluxgate compass. Should the MFD additionally require heading data to support its heading dependent features, then the NMEA 0183 output of the heading sensor should be paralleled and connected to both the NMEA 0183 inputs of the autopilot course computer and MFD ... or to the 4800 BAUD input leads of the AIS650 should it in turn be interfaced to the MFD via 38400 BAUD NMEA 0183 communications.