GX2200 GPS data to SpartPilot X5

[mkjones]

Hi everyone,

I searched the forums but couldn’t find a related thread. I’m wondering if there is a way to send the GPS data from the standard horizon gx2200 vhf/gps/ais to the SmartPilot X5. I tried wiring the NMEA 0183 out from the gx2200 directly to the NMEA in on the SmartPilot but it is not receiving any data. I tried wires on both
bauds but to no avail.

It would seem to me that this should be possible. Has anyone done it and how?
I asked raymarine but they wouldn’t help since it’s two different brands.

Thanks!

[continuouswave]

This inquiry has not been answered in three days. Perhaps I can help.

Originally Posted by mkjones

...I’m wondering if there is a way to send the GPS data from the standard horizon gx2200 vhf/gps/ais to the SmartPilot X5. I tried wiring the NMEA 0183 out from the gx2200 directly to the NMEA in on the SmartPilot but it is not receiving any data...

First, I doubt you want to send any data about the GPS to the autopilot. The autopilot most likely wants to get Course over Ground data and perhaps HEADING. It won't care how many GPS satellites are in view or what their carrier-to-noise power ratio might be. (See below for more comment on this.)

Second, you are correct that interconnection of two devices uses NMEA-0183 protocol should be able to send data between them.

My guess at the failure of your set-up involves two realms: wiring and configuration.

The wiring on NMEA-0183 can be confusing. Some devices have balanced signals, called TALKER A and TALKER B for example, and older, non-standard devices only have single-ended signals reference to chassis, or just TALKER A for example.

A further problem is that many vendors use non-standard nomenclature for the signal names, adding another layer of confusion. Names like Tx or Transmit or Output are used for TALKER, and names like RX or Receive are used for LISTENER.

Markings of polarity are often used. In most cases a (+) means A, and a (-) means B.

The rule for connecting in very simple:

(1) TALKER A/B connects to LISTENER A/B.

(2) If there is no TALKER B, then LISTENER B goes to chassis.

(3) If there is no LISTENER B, then TALKER a is left unconnected.

NOTE: I never offer advice about "color to color" wiring. You will have to figure out what wire insulation color on each device is carrying the TALKER A/B and LISTENER A/B signals yourself. There are endless permutations of this because many vendors have NOT followed the actual wire insulation colors specified for the interface in the protocol.

Now to the second step: configuration. You are already aware of the BAUD rate setting. In addition you must configure the DATA to be sent from a TALKER.

The DATA is identified in NMEA-0183 by acronyms of three-letters. Each NMEA-0183 "sentence" has an acronym.

Typically any device will list the sentences it can send by acronym, and also list the sentences it can receive and use for some purpose by acronym.

Carefully read the literature of the autopilot to find what NMEA-0183 sentence it needs.

Then carefully read the literature of the device with the GNSS receiver to see what sentences it can send.

Then configure the GNSS receiver and its TALKER to send the sentence needed.

The NMEA organization likes to keep the detail hidden, but the NMEA-0183 protocol is very well documented by users who have deduced all sorts of data. For help in figuring out the sentence acronyms and what data they will send, see

https://gpsd.gitlab.io/gpsd/NMEA.html

The autopilot probably wants the sentence RMC. See

https://gpsd.gitlab.io/gpsd/NMEA.htm...on_information

The autopilot may also want and prefer heading information, HDT. See

https://gpsd.gitlab.io/gpsd/NMEA.html#_hdt_heading_true

NOTE: the heading cannot be determined by a single GNSS receiver, so the GNSS receiver in the radio cannot possible send the actual heading; it will likely only send course over ground.

For more advice on making NMEA-0183 interconnections, read these articles I have written on that topic:

Guide to NMEA-0183 Interconnections
http://continuouswave.com/whaler/ref...eNMEA0183.html

Universal NMEA-0183 Interface Method
http://continuouswave.com/whaler/ref...lNMEA0183.html

ASIDE: many GNSS receivers will send data about themselves in sentences like

GBS - GPS Satellite Fault Detection
GNS - Fix data
GRS - GPS Range Residuals
GSA - GPS DOP and active satellites
GST - GPS Pseudorange Noise Statistics
GSV - Satellites in view

but generally an autopilot does not want or need this data about the GPS itself.

[smac999]

but generally an autopilot does not want or need this data about the GPS itself.

The gps output would also include cog and sog...

Likly neither are usefull on a slow sailboat. Sog to a power boat Sometimes going 5 knots and sometimes going 40kts helps control the pilot at different speeds.

Generally what you hook up to a pilot is waypoint route data from a plotter. Which a radio does not do.

[continuouswave]

Originally Posted by smac999

Generally what you hook up to a pilot is waypoint route data from a plotter. Which a radio does not do.

In order for an autopilot to steer to a waypoint, it first has to know the boat's heading.

[Sailmonkey]

Originally Posted by smac999

The gps output would also include cog and sog...



Likly neither are usefull on a slow sailboat. Sog to a power boat Sometimes going 5 knots and sometimes going 40kts helps control the pilot at different speeds.



Generally what you hook up to a pilot is waypoint route data from a plotter. Which a radio does not do.

Actually you can enter a waypoint into the radio. This would allow the pilot to steer a course directly to the waypoint.

OP, did you try reversing the polarity of the wires you’ve got attached? Just swap the leads?

[smac999]

Originally Posted by continuouswave

In order for an autopilot to steer to a waypoint, it first has to know the boat's heading.

Every pilot comes with a heading sensor in the box...