The EDL21 over LoRaWAN bridge is a device that can be used to readout modern utility meters with standardized infrared "INFO" interface.

These type of meters are called in Germany to be "EDL21"-compatible - hence the name. The meter outputs over its infrared "INFO" interface a serial protocol conforming to the Smart Meter Language Protocol 1.04 (SML). This interface is intended to be used by end-users and not for billing purposes of the electricity supplier. The read information normally contains the current consumption values of the meter and gets interpreted and forwarded by the EDL21 bridge via a LoRaWAN network to web based applications interested in further processing this data.

Top Features

 LoRaWAN 1.0.x and 1.1 network servers supported

 LoRaWAN time synchronisation

 Configuration via USB or remotely via LoRaWAN downlink

 Compatible with many electrical utility meters

Configure up to 25 Obis Codes to be read

 RGB Status LED

Separation of infrared readout head possible

Testmode for protocol and supported obis code identification

Compatible utility meters

Any meter that adheres to the standard can be read. The following list contains meters that we successfully tested.

Product variants

EDL21-LoRaWAN Bridge (universal head, current transformer, int. Ant.), Order number: 8000160
 

Additional Equipment

Battery Pack, Order Number: 8000164

The optional Battery Pack has 2 functions. The main function is to supply the device with energy for initial testing without having to wait for the current transformer. After connecting the battery pack for the first time it will take about 30 seconds to load the bridges supercapacitor. The secondary function is to provide a simple way to reset the device with an inbuilt magnet. If the red dot on the battery pack is brought near the bridge the bridge will signal its presence by activating its LED. After 1 second it will blink rapidly and reset.

Quickstart

1. Connect to the device with the Lobaro Tool using the Lobaro Config Adapter
2. Under Configuration click "Reload Config" and change the fields ReadCron and ObisCode as you need followed by clicking on "Write to Device", here you can see a configuration example.
   
3. Register the device in your LoRaWAN network
4. Place the EDL21 opto head on the "Info" interface
5. Install Current Transformer and connect it to the device (or for a quick check use the optional battery pack)
6. As soon as the EDL21 receives data its green LED will light up for 5 seconds, when connected to a LoRa Network its blue LED will light up for 5 seconds
7. If data is available it will be transmitted on port 3 or 4 depending on the chosen format. If not a status message will be sent. Check the Error Flags for possible reasons.

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

Configuration values defining the behaviour of the device.

See also our Introduction to Cron expressions and our Introduction to Obis Codes.

LED blinking patterns

The following pattery are explained in the order in which they appear after initial power on / reset of the device.

Payload

Payload Format Status Packet (Port 64)

Once per day a status packet will be sent. It contains basic information about the device. The Battery Voltage is transmitted in 1/1000 V and the temperature in 1/10 °C. Both are in Big Endian byte order.

The "Flags" field represents different error conditions by setting the individual bits:

Payload Format 1 (default, Port 3, with exponent)

This Format is used, when the configuration parameter PayloadFormat is set to 1 (which is the default value).

The payload consists of multiple entries, one entry per OBIS code given in the configuration. Each entry follows the following structure:

Example packet: 01 00 01 08 00 FE 08 FF 01 00 00 00 00 00 00 ff 01 00 01 08 00 FE 08 FF 02 00 00 00 00 00 00 02

Entry 1:

Entry 2:

Multiple messages

The Bridge puts as many values in a single data message as possible (respecting the current Spreading Factor). When it cannot fit all values in a single message, it will send multiple data messages until all values are uploaded. It will never split a single value. Since every value is prefixed with the Obis code, the parser can easily assign values to Obis codes.

Payload Format 2 (extended, Port 4, with timestamp)

This Format is used, when the configuration parameter PayloadFormat is set to 2.

The Obis Codes and Data Values are transmitted as in Payload Format 1, but each uploaded LoRaWAN-Message with data is prefixed with a 5 byte Timestamp, indicating when the values where requested from the attached meter. This allows for a more precise timing information then using the time of reception, as the upload can be delayed quite heavily due to our random delay feature and potentially due to duty cycle restrictions. The timestamp also makes it easy to reassociate values from multiple uplinks to a single reading, when multiple uplinks must be used to upload all values. If a readout is spilt over multiple uplinks (because of LoRaWAN's length restrictions), every uplink from that reading will have the same timestamp (which is the time of requesting the values from the meter).

The Timestamp is sent as a UNIX-Timestamp encoded as a bigendian signed 40-bit number.

Test Mode

If TestMode is enabled in the configuration the device will not enter normal operation but check for different possible meter output protocols. Received data will be shown in the Log and parsed if possible. After completing the detection the result will be presented 10 times as blinking pattern via LED. After that the testing cycle will start again. The Log-Output can also be used to identify available OBIS Codes.

Reference decoder

This is a decoder written in JavaScript that can be used to parse the device's LoRaWAN messages. It can be used as is in The Things Network.

function readName(bytes, i) {
    return bytes.slice(i, i + 6);
}

function readValue(len, bytes, i) {
    if (len <= 0) {
        return [];
    }
    return bytes.slice(i, i + len);
}

function toHexString(byteArray) {
    var s = '';
    byteArray.forEach(function (byte) {
        s += ('0' + (byte & 0xFF).toString(16)).slice(-2);
    });
    return s;
}

function signed(val, bits) {
    if ((val & 1 << (bits - 1)) > 0) { // value is negative (16bit 2's complement)
        var mask = Math.pow(2, bits) - 1;
        val = (~val & mask) + 1; // invert all bits & add 1 => now positive value
        val = val * -1;
    }
    return val;
}
function uint40_BE(bytes, idx) {
    bytes = bytes.slice(idx || 0);
    return bytes[0] << 32 |
        bytes[1] << 24 | bytes[2] << 16 | bytes[3] << 8 | bytes[4] << 0;
}
function uint16_BE(bytes, idx) {
    bytes = bytes.slice(idx || 0);
    return bytes[0] << 8 | bytes[1] << 0;
}
function int40_BE(bytes, idx) {return signed(uint40_BE(bytes, idx), 40);}
function int16_BE(bytes, idx) {return signed(uint16_BE(bytes, idx), 16);}
function int8(bytes, idx) {return signed(bytes[idx || 0], 8);}  

function toNumber(bytes) {
    var res = 0;

    for (var i = bytes.length-1; i >= 0 ; i--) {
        res *= 256;
        res += bytes[i];
    }
    
    return res;
}  

function readVersion(bytes) {
    if (bytes.length<3) {
        return null;
    }
    return "v" + bytes[0] + "." + bytes[1] + "." + bytes[2];
}

function decodeStatus(bytes) {
    var decoded = {
        "version":readVersion(bytes),
        "flags": bytes[3],
        "vBat": uint16_BE(bytes, 4) / 1000,
        "temp": int16_BE(bytes, 6) / 10,
    };

    return decoded;
}

function decodeSmlValuesV1(bytes) {
    var decoded = {
        values: [],
    };

    if (bytes.length === 1) {
        // No Data! Read error?
        return decoded;
    }

    var pos = 0;
    while (pos < bytes.length) {
        var name = readName(bytes, pos);
        pos += 6;
        var len = bytes[pos];
        pos += 1;
        var value = readValue(len, bytes, pos);
        pos += len;

        var val = {
            nameHex: toHexString(name),
            len: len,
            value: toNumber(value),
            valueHex: toHexString(value)
        };

        decoded.values.push(val);
    }

    return decoded;
}

function decodeSmlValuesV2(bytes) {
    var decoded = {
        values: [],
    };

    if (bytes.length === 1) {
        // No Data! Read error?
        return decoded;
    }

    var pos = 0;
    while (pos < bytes.length) {
        var name = readName(bytes, pos);
        pos += 6;
        var len = bytes[pos];
        pos += 1;
        var value = readValue(len, bytes, pos);
        pos += len;
        if (len > 0) {
            var exponent = int8(bytes, pos);
            pos += 1;
        }
        var val;
        if (len > 0) {
            val = {
                nameHex: toHexString(name),
                len: len,
                value: toNumber(value) * Math.pow(10, exponent),
                valueHex: toHexString(value),
            }
        } else {
            val = {
                nameHex: toHexString(name),
                len: len,
                value: toNumber(value),
                valueHex: toHexString(value),
            }
        }

        decoded.values.push(val);
    }

    return decoded;
}

function decodeSmlValuesV3(bytes) {
    // Like V2, but with 5B timestamp as prefix:
    var decoded = decodeSmlValuesV2(bytes.slice(5));
    decoded.time = int40_BE(bytes, 0) * 1000;
    return decoded;
}

function Decoder(bytes, port) {
    // Decode an uplink message from a buffer
    // (array) of bytes to an object of fields.
    switch (port) {
        case 1:
            return decodeStatus(bytes);
        case 2:
            return decodeSmlValuesV1(bytes);
        case 3:
            return decodeSmlValuesV2(bytes);
        case 4:
            return decodeSmlValuesV3(bytes);
    }
}

Example parser result

Test input (Port 3): 01 00 01 08 00 FE 08 FF 01 00 00 00 00 00 00 FF

{
  "values": [
    {
      "len": 8,
      "nameHex": "0100010800fe",
      "value": 51.1,
      "valueHex": "ff01000000000000"
    }
  ]
}

Appendices

Technical characteristics

Disposal / WEEE / Entsorgung

Information about the disposal of the Device.

CE Declaration of Conformity

CE Declaration of Conformity (pdf).