ST1000+ to GPS connection

[guyfeltenstein]

I have recently purchased a new ST1000+ tiller auto-pilot from RayMarine.

I currently do not have a navigation system, short of an older handheld Garmin GPS12. The GPS works wonderfully, despite it's lack of a mapping feature.

From everything that I have read, using the data cable, which I have, for the GPS 12, I should be able to connect the GPS to the auto pilot. The GPS has a single "data out" pin and a ground, and the tiller has a "NMEA data+" and a "NMEA data-" pin. I would assume that I could connect the "NMEA data+" pin on the to the to the GPS's "data out" pin and the GPS's "ground" pin.

Thoughts? Am I over simplifying this?

Guy Feltenstein
1976 Ranger 28'
Annapolis, MD

[negrini]

Guy,

To simplify, yes you can connect the data- to ground, and data+ to data out. This is considering the simplicity of use, where you could set the lowest baudrate possible, and the very short cable lenght you might be using.
In reality, your AP uses RS422 (current loop and more robust against line noise/drain/etc) instead old GPS RS 232, voltage sensitive. But you'll probably use a short piece of cable, routed close to the AP, free from magnetic/electric noise, and you could set your data baudrate (if possible) less than 4800, then your system would not suffer from the mismatch. Well, this is not compliant to ABYC recommendation, but works ....

[sailingdog]

Make sure you set the Garmin's serial port to output NMEA 0183, 4800 8 N 1.

[hellosailor]

Guy, I've got one of the old 12XL's myself and much as it isn't fancy--the damned thing just keeps working, and I give it credit for that. You can pick up a combined data/power cable, so you can plug it into ships' power (or a cigarette lighter socket, just use a good quality one) and data connection at the same time. With that and a good set of NiCd or NiMh cells--you're set. With the GPS running mainly off ship's power, you will be able to get 6+ months from those batteries before you need to swap them out. Very convenient. (And I *think* they recharge while the power is connected.)

[guyfeltenstein]

Thanks for the input!

It just seemed overly simple to me, given the lack of settings options on the GPS 12. But from what I have read, the NMEA standard not only includes the data format, but the baud rate and parity as well, so those settings are assumed by all NMEA devices. I'll let you guys know how it comes out. Thanks again.

Guy Feltenstein
1976 Ranger 28'
Annapolis, MD

[sailingdog]

Yes, the NMEA 0183 specification includes baud rate, byte size, stop bits, parity, but in many situations, like using it with a laptop, you might want to up the data rate.... so you have make sure it is set for 4800, which is the NMEA specification.

Originally Posted by guyfeltenstein

Thanks for the input!

It just seemed overly simple to me, given the lack of settings options on the GPS 12. But from what I have read, the NMEA standard not only includes the data format, but the baud rate and parity as well, so those settings are assumed by all NMEA devices. I'll let you guys know how it comes out. Thanks again.

Guy Feltenstein
1976 Ranger 28'
Annapolis, MD