[CA] [CA11] NMEA0183 Wind Steering on ST2000

[bretthoward]

I'm trying to get wind steering to work on my ST2000. But I'm building my own wind instrument. It has a wireless transmitter at the mast head that the wind instruments picks up and displays. Then there is also another unit that picks up the same wireless transmissions and it will transmit NMEA into the ST2000.

Right now I'm not on the boat but I'm just trying to get things debugged before I launch again in about a month. I have the reception of messages and formatting the NMEA working to the best of my knowledge. Here are some sample messages from a hard coded example that I've been trying to test with:

$IIVWR,042.0,R,1.2,N,0.6,M,2.2,K*4A
$IIVWR,045.0,R,1.2,N,0.6,M,2.2,K*4D

I have it send a message every 100mS at 42 degrees for 10 seconds and then I have the wind shift to 45 degrees...

So far I've tried hooking the 0-3.3V TTL RS-232 directly to the NMEA+ and NMEA- pins and that does not seem to work. I've also installed a buffer that should be bringing it to 5V but its a bi-directional buffer that uses pull resistors and that seems to only give a 0-2.5V signal strength.

I've ordered a full proper RS422 driver that I'll be installing here in the next couple days to test... But I've been finding that the unit does nothing when I press STBY and AUTO at the same time... Is it normal that it won't enter the mode unless it is receiving NMEA strings? I noticed that it will go into track mode even if messages aren't coming in so I was a bit concerned... Any help would be greatly appreciated!