Multi Temperature Sensor Box (LoRaWAN)

Order Codes / Variants

• 8000072: Default Variant
• 8000150: Special Variant without external probe and cable glant (only on special sales request)

Quickstart

1. Connect to the device with the Lobaro Tool using the Lobaro Config Adapter
2. Under Configuration click "Reload Config" and change the configuration according to your needs
3. Register the device in your LoRaWAN network
4. Connect ER34614 3.6V D-cell Battery via XH connector / Connect external powersupply

Key Features

•  Supports up to 25 DS18x20 1-Wire sensors
•  8-Port easy installation Hub available
•  IP67 outdoor housing with pressure compensating element
•  Comes with one sensor attached
•  Sensor output order can be configured
•  Testmode for easy sensor identification
•  Big 19Ah size "D" battery for 10 years+ possible battery lifetime (not included)
•  LoRaWAN 1.0.x and 1.1 network servers supported
•  LoRaWAN Class A or Class C operation
•  LoRaWAN 1.1 time synchronisation
•  Variant with external power-supply and or external antenna available on request
•  Quick closing screws with cover retainer on housing

Target Measurement / Purpose

The Multi Temperature Sensor Box is used to read out up to up to 25 DS18x20 1-Wire temperature sensors. The temperature from all sensors is read regualarly and sent via LoRaWAN uplink automatically splitting the data into multiple uplinks if the payload gets too big for a single LoRaWAN message. Sensors can be attached in series or in star configuration.

Additional Hardware

For easy connection of up to 7 DS18x20 1-Wire sensors consider using our Modbus & 1-Wire 8-Port Hub (Order number: 8000130). Multiple Hubs can be connected to each other to achieve the limit of 25 sensors per Box.

Configuration

The configuration is done using Lobaro Maintenance Tool and the Lobaro USB PC adapter.

LoRaWAN

The connection to the LoRaWAN network is defined by multiple configuration parameters. This need to be set according to your LoRaWAN network and the way your device is supposed to be attached to it, or the device will not be able to send any data.

For a detailed introduction into how this values need to be configured, please refer to the chapter LoRaWAN configuration in our LoRaWAN background article.

Operation

Without configuration the sensors will be transmitted ordered by the 48 Bit id, ignoring the Sensorfamily prefix and the Checksum.

^† See also our Introduction to Cron expressions.

Temperature and Error values

Temperature is transmitted in 10^th of degrees Centigrade (d°C), to avoid having to deal with floating point numbers. Error conditions for individual sensors are transmitted as temperatures below -300°C.

Sensor IDs

A complete sensor ID consists of 8 bytes:

byte    0: family code
bytes 1-6: serial number
byte    7: crc cecksum 

Only the serial number is used by the device. Family code and checksum are omitted for uploads and in configuration.

Internal Sensor

There is a temperature sensor included in the board of the device. If SendInternalTemp is set to true, that sensor will be included in uploads. It will always be the first sensor in the list.

Sensor order

The sensors will be ordered by their IDs (without the leading byte indicating the sensor type). You can fix the upload order by listing sensors in SensorIdOrder. Sensors included here will always be included in upload messages, whether the sensor is found or not. If the sensor cannot be found, a temperature value of -899.0°C (=0xdce2) is sent.

If the internal sensor is included (by SendInternalTemp=true), the internal sensor will still be sent first, before the first sensor listed in SensorIdOrder.

Any sensors that are found and are neither internal nor listed in SensorIdOrder will be appended after the last sensor from SensorIdOrder, ordered by their IDs.

Payload

Example payloads for each port:

Status Message (Port 1)

Payload: 00040001070ce3

Decoded:

{
  "temp": 26.3,
  "vBat": 3.299,
  "version": "v0.4.0"
}

Data Message (Port 2)

Payload with temperature measurements when Sensor-ID is included.

Structure:

When the total length of data exceeds 50 bytes, the message will be split and uploaded in multiple packets using this format.

Example Payload: 01551e46920d0200da96b446920c0200d7dafc46920d0200d5202e4692050200dc

Decoded:

{
  "sensors": [
    {
      "id": "551e46920d02",
      "temp": 21.8
    },
    {
      "id": "96b446920c02",
      "temp": 21.5
    },
    {
      "id": "dafc46920d02",
      "temp": 21.3
    },
    {
      "id": "202e46920502",
      "temp": 22
    }
  ],
  "success": true
}

Data Message (Port 3)

Payload with temperature measurements when Sensor-ID is omitted.

Before v0.4.0 this format is sent on Port 2.

Structure:

When the total length of data exceeds 50 bytes, the message will be split and uploaded in multiple packets using this format.

Example Payload: 0100f500f500f800f500f300f8

Decoded:

{
    "sensors": [
      24.5,
      24.5,
      24.8,
      24.5,
      24.3,
      24.8
    ],
    "success": true}

Parser

TheThingsNetwork (TTN) / ChirpStack

function readVersion(bytes) {
    if (bytes.length<3) {
        return null;
    }
    return "v" + bytes[0] + "." + bytes[1] + "." + bytes[2];
}
function parse_sint16(bytes, idx) {
    bytes = bytes.slice(idx || 0);
    var t = bytes[0] << 8 | bytes[1] << 0;
    if( (t & 1<<15) > 0){ // temp is negative (16bit 2's complement)
        t = ((~t)& 0xffff)+1; // invert 16bits & add 1 => now positive value
        t=t*-1;
    }
    return t;
}
function parse_uint16(bytes, idx) {
    bytes = bytes.slice(idx || 0);
    var t = bytes[0] << 8 | bytes[1] << 0;
    return t;
}

function parse_hex(bytes, idx, end) {
    var chars = "0123456789abcdef";
    bytes = bytes.slice(idx || 0, end || null);
    var s = "";
    for (var i=0; i<bytes.length; i++) {
        var byte = bytes[i];
        s += chars.charAt(byte>>4);
        s += chars.charAt(byte & 0xf);
    }
    return s;
}

function DecoderPort1(bytes) {
    return {
        "version":readVersion(bytes),
        "temp": parse_sint16(bytes, 3) / 10,
        "vBat": parse_uint16(bytes, 5) / 1000,
    };
}

function DecoderPort2(bytes) {
    // Decode an uplink message from a buffer
    // (array) of bytes to an object of fields.
    var sensors = [];
    var success = false;

    var pos = 0;
    if ( bytes.length ) {
        pos+=1;
        success = bytes[0] !== 0;
    }
    var left = bytes.length - pos;
    while (left>=8) {
        var sensor = {
            //'id_': bytes.slice(pos, pos+6),
            'id': parse_hex(bytes, pos, pos+6),
            'temp': parse_sint16(bytes, pos+6) / 10.0
        };
        sensors.push(sensor);
        pos += 8;
        left = bytes.length - pos;
    }
    // if (port === 1) decoded.led = bytes[0];

    var decoded = {};
    decoded['success'] = success;
    decoded['sensors'] = sensors;
    return decoded;
}

function DecoderPort3(bytes) {
    // Decode an uplink message from a buffer
    // (array) of bytes to an object of fields.
    var sensors = [];
    var success = false;

    var pos = 0;
    if ( bytes.length ) {
        pos+=1;
        success = bytes[0] !== 0;
    }
    var left = bytes.length - pos;
    var nr=0;
    while (left>=2) {
      var temp = parse_sint16(bytes, pos) / 10.0
        sensors.push(temp);
        pos += 2;
        left = bytes.length - pos;
    }
    // if (port === 1) decoded.led = bytes[0];

    var decoded = {};
    decoded['success'] = success;
    decoded['sensors'] = sensors;
    return decoded;
}

function Decoder(bytes, port) {
    switch (port) {
        case 1:
            return DecoderPort1(bytes);
        case 2:
            return DecoderPort2(bytes);
        case 3:
            return DecoderPort3(bytes);
    }
    return {
        "error": "Invalid port",
        "port": port
    };
}

// Wrapper for Lobaro Platform
function Parse(input) {
    // Decode an incoming message to an object of fields.
    var b = bytes(atob(input.data));
    var decoded = Decoder(b, input.fPort);

    return decoded;
}

// Wrapper for Loraserver / ChirpStack
function Decode(fPort, bytes) {
    return Decoder(bytes, fPort);
}

// Wrapper for Digimondo niota platform
/*
module.exports = function (payload, meta) {
    const port = meta.lora.fport;
    const buf = Buffer.from(payload, 'hex');

    return Decoder(buf, port);
}
*/

CE Declaration of Conformity

CE Declaration of Conformity (pdf).