// V3.0 10.05.2022, copyright by Tesenso GmbH
//Code entry
if (msg.data) {
var decoded = decodeFromHex(msg.data);
decoded.ts = msg.ts;
decoded.rssi = msg.rssi;
decoded.snr = msg.snr;
decoded.toa = msg.toa;
decoded.frequency = msg.frequency;
decoded.dr = msg.dr;
decoded.bat = decodeBattery(msg.bat);
decoded.hex = msg.data;
return {
msg: decoded,
metadata: metadata,
msgType: msgType
};
} else {
return {
msg: msg,
metadata: metadata,
msgType: msgType
};
}
function decodeFromHex(data) {
// Decode uplink message
var decoded = {};
//Parse string as bytes
var bytes = parseHexString(data);
//scale to manage the different scales with none, one or more decimals on the meter.
var scale = metadata.ss_scale;
//various info that can be extracted
var length = bytes[0];
var msgType = bytes[1];
var slaveCount = bytes[2];
var startCharacter1 = bytes[3];
var length1 = bytes[4];
var length2 = bytes[5];
var startCharacter2 = bytes[6];
var c = bytes[7];
var a = bytes[8];
//72 or 76 -> variable; 73 or 77 -> fixed
var ciField = bytes[9];
var medium = data.substr(34, 2);
var checkSum = bytes[36];
//Different medium IDs, register positions vary
if (medium == "02") {
var volume = data.substr(72, 2) + data.substr(70,
2) + data.substr(68, 2) + data.substr(66, 2);
decoded.electricityMeterEnergyHt = parseInt(volume,
16) * scale;
volume = data.substr(88, 2) + data.substr(86, 2) +
data.substr(84, 2) + data.substr(82, 2);
decoded.electricityMeterEnergyNt = parseInt(volume,
16) * scale;
}
if (medium == "03") {
var volume = data.substr(66, 2) + data.substr(64,
2) + data.substr(62, 2) + data.substr(60, 2);
decoded.gasMeterVolume = parseInt(volume) * scale;
}
if (medium == "16") {
var volume = data.substr(54, 2) + data.substr(52,
2) + data.substr(50, 2) + data.substr(48, 2);
decoded.waterMeter = parseInt(volume, 16) * scale;
}
return decoded;
}
//Helper functions
function parseHexString(hex) {
for (var bytes = [], c = 0; c < hex.length; c += 2)
bytes.push(parseInt(hex.substr(c, 2), 16));
return bytes;
}
function decodeBattery(byte) {
if (byte == 0) {
return 'External power source';
} else if (byte > 0 && byte < 255) {
return byte / 254 * 100;
} else {
return 'Unknown battery state';
}
}
function parseFloat(str) {
var float = 0,
sign, order, mantissa, exp,
int = 0,
multi = 1;
if (/^0x/.exec(str)) {
int = parseInt(str, 16);
} else {
for (var i = str.length - 1; i >= 0; i -= 1) {
if (str.charCodeAt(i) > 255) {
console.log('Wrong string parameter');
return false;
}
int += str.charCodeAt(i) * multi;
multi *= 256;
}
}
sign = (int >>> 31) ? -1 : 1;
exp = (int >>> 23 & 0xff) - 127;
mantissa = ((int & 0x7fffff) + 0x800000).toString(2);
for (i = 0; i < mantissa.length; i += 1) {
float += parseInt(mantissa[i]) ? Math.pow(2, exp) :
0;
exp--;
}
return float * sign;
}
