node-nmea/codecs/MWV.js

44 lines
1.1 KiB
JavaScript

var helpers = require("../helpers.js")
/*
=== MWV - Wind Speed and Angle ===
------------------------------------------------------------------------------
*******1 2 3 4 5
*******| | | | |
$--MWV,x.x,a,x.x,a*hh<CR><LF>
------------------------------------------------------------------------------
Field Number:
1. Wind Angle, 0 to 360 degrees
2. Reference, R = Relative, T = True
3. Wind Speed
4. Wind Speed Units, K/M/N
5. Status, A = Data Valid
6. Checksum
*/
exports.TYPE = 'wind';
exports.ID = 'MWV';
exports.decode = function(fields) {
return {
sentence: exports.ID,
type: exports.TYPE,
angle: +fields[1],
reference: fields[2],
speed: +fields[3],
units: fields[4],
status: fields[5]
}
}
exports.encode = function(talker, msg) {
var result = ['$' + talker + exports.ID];
result.push(helpers.encodeDegrees(msg.angle));
result.push(msg.reference);
result.push(helpers.encodeFixed(msg.speed, 2));
result.push(msg.units);
result.push(typeof msg.status === undefined ? 'A' : msg.status);
var resultMsg = result.join(',');
return resultMsg + helpers.computeChecksum(resultMsg);
}