Lobaro Pressure and Temperature Sensor

To read out the pressure & temperature probe, the Hybrid Modbus Gateway must be configured as follows:

Parameter	Value	Comment
`PlFmt`	5	Sets the payload to a short format.
`MbCmd`	0 0/5 * * * *:R,9600,8N1:010300160002,010300260002	Reads the Registers 22-23 and 34-35. The CRON Expressions can be adjusted to set time of sensor reading.
`PowerOnDelay`	1500	Battery variant only. Sets time (in ms) between activating sensor power and reading value (time for sensor to be ready).

Data Uplink (Port 20)

Bytes | 0 .    | 1 . 2 . 3 . 4 . | 5 . 6 . 7 . 8 . |
------+--------+-----------------+-----------------+
Field | Header | Pressure        | Temperature     |

Field	Type	Value
Header	`uint8`	`0x00` on success, `0x80` if an error occurred
Pressure	`float32`	Pressure in `mH2O`, `ffffffff` on error.
Temperature	`float32`	Temperature in `°C`, `ffffffff` on error.

Example

# Example of a successful measurement
'003d94ce4541b7a512'
  '00'       -> Successful readout
  '3d94ce45' -> 0.073 mH2O
  '41b7a512' -> 22.96 °C

# Example
'80ffffffffffffffff'
  '80'       -> An error occurred.
  'ffffffff' -> Pressure could not be read.
  'ffffffff' -> Temperature could not be read.

Reference Parser

see below

Lobaro Pressure Sensor

Reading from the Lobaro Pressure Sensor using the Hybrid Gateway can be done by setting the following parameters in the configuration:

Parameter	Value	Comment
`PlFmt`	5	Sets the payload to a short format.
`MbCmd`	0 0/5 * * * *:R,9600,8N1:010300020003	Reads the Registers 2 to 4. The CRON Expressions can be adjusted to set time of sensor reading.
`PowerOnDelay`	1500	Battery variant only. Sets time (in ms) between activating sensor power and reading value (time for sensor to be ready).

Data Uplink (Port 20)

Bytes | 0 .    | 1 . 2 . | 5 . 6 .   | 7 . 8    |
------+--------+---------+-----------+----------+
Field | Header | Unit    | Precision | Pressure |

Field	Type	Value
Header	`uint8`	`0x00` on success, `0x80` if an error occurred
Unit	`uint16BE`	`0x0007` = mH2O
Precision	`uint16BE`	`0x0003` = 3 decimals
Pressure	`int16BE`	Pressure in mH2O

Example

# Example of a successful measurement
'00000700030211'
  '00'       -> Successful readout
  '0007' -> 0.073 mH2O
  '0003' -> 22.96 °C
  '0211' -> 529 -> 0.529 mH2O

Reference Parser

/**
 * Parser for Lobaro Pressure Probe via LoRaWAN (hybrid gateway).
 * Usable for Pressure Probe as or with Presure+Temperature Probe.
 * Works with TTN, ChirpStack, or the Lobaro Platform.
 */
function signed(val, bits) {
    // max positive value possible for signed int with bits:
    var mx = Math.pow(2, bits-1);
    if (val < mx) {
        // is positive value, just return
        return val;
    } else {
        // is negative value, convert to neg:
        return val - (2 * mx);
    }
}
function int16_BE(bytes, idx) {
    bytes = bytes.slice(idx || 0);
    return signed(bytes[0] << 8 | bytes[1] << 0, 2*8);
}
function uint16_BE(bytes, idx) {
    bytes = bytes.slice(idx || 0);
    return bytes[0] << 8 | bytes[1] << 0;
}
function uint32_BE(bytes, idx) {
    bytes = bytes.slice(idx || 0);
    return bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3] << 0;
}
function float32FromInt(asInt) {
    var sign = (asInt & 0x80000000) ? -1 : 1;
    var exponent = ((asInt >> 23) & 0xFF) - 127;
    var significand = (asInt & ~(-1 << 23));
    if (exponent === 128)
        return null;
        // return sign * ((significand) ? Number.NaN : Number.POSITIVE_INFINITY);
    if (exponent === -127) {
        if (significand === 0) return sign * 0.0;
        exponent = -126;
        significand /= (1 << 22);
    } else significand = (significand | (1 << 23)) / (1 << 23);
    return sign * significand * Math.pow(2, exponent);
}
function float32_BE(bytes, idx) { return float32FromInt(uint32_BE(bytes, idx)); }

/**
 * TTN decoder function.
 */
function Decoder(bytes, port) {
    var vals = {};
    if( port == 20 ){
        if (bytes.length==7) {
          // Pressure Probe without temperature sensor
          // make sure that unit is mH2O and precision is 3 decimals
          if( (uint16_BE(bytes, 1)==7) && (uint16_BE(bytes, 3)==3)){
            vals["error"] = !!(bytes[0]&0x80);
            vals["pressure"] = int16_BE(bytes, 5)/1000;
          }
          else{
            vals["error"] = true;
            vals["pressure"] = null;
          }
        } else if (bytes.length==9) {
          vals["error"] = !!(bytes[0]&0x80);
          // pressure in mH2O
          vals["pressure"] = float32_BE(bytes, 1);
          // temperature in Degree Celsius
          vals["temperature"] = float32_BE(bytes, 5);
        }
    } 
    return vals;
}
 
/**
 * TTN V3 Wrapper
 */
function decodeUplink(input) {
   return {
    data: {
      values: Decoder(input.bytes, input.fPort)
    },
    warnings: [],
    errors: []
  };
} 
 
/**
 * ChirpStack decoder function.
 */
function Decode(fPort, bytes) {
    // wrap TTN Decoder:
    return Decoder(bytes, fPort);
}
 
/**
 * Lobaro Platform decoder function.
 */
function Parse(input) {
    var data = bytes(atob(input.data));
    var port = input.fPort;
    return Decoder(data, port);
}