MLR003 Encoder/Decoder Chirpstack

// Decode uplink function.
//
// Input is an object with the following fields:
// - bytes = Byte array containing the uplink payload, e.g. [255, 230, 255, 0]
// - fPort = Uplink fPort.
// - variables = Object containing the configured device variables.
//
// Output must be an object with the following fields:
// - output = Object representing the decoded payload.
function decodeUplink(input) {
  return {
    data: Decode(input.fPort, input.bytes, input.variables)
  };
}

function get_user_mode(input) {
  var user_mode = input[9] & 0x7;
  switch (user_mode) {
    case 0:
      return "Valve_Position";
    case 1:
      return "RESERVED";
    case 2:
      return "SP_Ambient_Temperature";
    case 3:
      return "Detecting_Opening_Point";
    case 4:
      return "Slow_Harvesting";
    case 5:
      return "Temperature_Drop";
    case 6:
      return "Freeze_Protect";
    case 7:
      return "Forced_Heating";
    default:
      return "Unknown Operating Mode";
  }
}

function get_user_value(input) {
  var user_mode = get_user_mode(input);
  switch (user_mode) {
    case "Valve_Position":
    case "Freeze_Protect":
    case "Forced_Heating":
      return input[10];
    case "SP_Ambient_Temperature":
      return input[10] * 0.5;
    case "Detecting_Opening_Point":
    case "Slow_Harvesting":
      return input[10] * 0.25;
    default:
      return "Invalid User Mode";
  }
}

function decode_port_1(input) {
  var output = {
    Current_Valve_Position: input[0],
    Flow_Sensor_Raw: input[1] * 0.5,
    Flow_Temperature: input[2] * 0.5,
    Ambient_Sensor_Raw: input[3] * 0.25,
    Ambient_Temperature: input[4] * 0.25,
    Temperature_Drop_Detection: input[5] >> 7 & 0x01,
    Energy_Storage: input[5] >> 6 & 0x01,
    Harvesting_Active: input[5] >> 5 & 0x01,
    Ambient_Sensor_Failure: input[5] >> 4 & 0x01,
    Flow_Sensor_Failure: input[5] >> 3 & 0x01,
    Radio_Communication_Error: input[5] >> 2 & 0x01,
    Received_Signal_Strength: input[5] >> 1 & 0x01,
    Motor_Error: input[5] >> 0 & 0x01,
    Storage_Voltage: Number((input[6] * 0.02).toFixed(2)),
    Average_Current_Consumed: input[7] * 10,
    Average_Current_Generated: input[8] * 10,
    Operating_Condition: input[9] >> 7 & 0x01,
    Storage_Fully_Charged: input[9] >> 6 & 0x01,
    Zero_Error: input[9] >> 5 & 0x01,
    Calibration_OK: input[9] >> 4 & 0x01,
  }
  output.User_Mode = get_user_mode(input);
  output.User_Value = get_user_value(input);

  if (input.length == 12) {
    utmp = input[11] * 0.25;
    output.Used_Temperature = utmp;
  }
  return output;
}


function Decode(fPort, bytes) {
  var output = {};
  switch (fPort) {
    case 1:
      output = decode_port_1(bytes);
      break;
    default:
      return {
        errors: ['unknown FPort'],
      };
  }
  return output;
}

// Encode downlink function.
//
// Input is an object with the following fields:
// - output = Object representing the payload that must be encoded.
// - variables = Object containing the configured device variables.
//
// Output must be an object with the following fields:
// - bytes = Byte array containing the downlink payload.
function encodeDownlink(input) {
  var encoded = [];

  if ("Valve_Position" in input.data) {
    var new_vp = input.data.Valve_Position;
    encoded = [new_vp, 0x00, 0x26, 0x00, 0x00, 0x00];
  }

  if ("Set_Point_Ambient_Temperature" in input.data) {
    var new_spt = (input.data.Set_Point_Ambient_Temperature) * 2;
    encoded = [new_spt, 0x00, 0x26, 0x08, 0x00, 0x00];
  }

  return { bytes: encoded };
}

{"Set_Point_Ambient_Temperature":22}

{"Valve_Position":100}