{
 "manufacturer": "Vaisala",
 "manufacturer_slug": "vaisala",
 "model": "HMW90 series humidity and temperature transmitter (BACnet MS/TP)",
 "model_slug": "hmw90",
 "aliases": [
  "HMW95",
  "HMW90 BACnet",
  "XMW90",
  "Vaisala humidity transmitter BACnet",
  "M211399EN"
 ],
 "equipment_type": "Humidity and temperature sensor (wall transmitter)",
 "applies_to": "Vaisala HMW90 series wall transmitters with digital output (HMW95 models), set to the BACnet MS/TP protocol.",
 "summary": "The digital HMW95 transmitter measures relative humidity and temperature and calculates dewpoint, wet bulb, absolute humidity, mixing ratio and enthalpy. On BACnet MS/TP each value is an Analog Input; two writable Analog Values set the operating pressure or altitude used in the humidity calculations.",
 "bacnet_transport": [
  "BACnet MS/TP"
 ],
 "firmware": "Application software 1.0.28 (firmware 1.0.0.0)",
 "default_device_instance": "Unique value set at the factory",
 "access_inferred": false,
 "notes": [
  "Calculated humidity objects (AI 4-10) exist only on the digital HMW95 models.",
  "AV 1 OPER P and AV 2 OPER Altitude are linked: writing one recalculates the other.",
  "Analog Input Present_Value can be written only when Out_Of_Service is set.",
  "The manual prints the same description 'Dewpoint' for both Td (AI 4) and Tdf (AI 5).",
  "Source: HMW90 Series User's Guide M211399EN-H, Appendix A (BACnet reference)."
 ],
 "source": {
  "title": "HMW90 Series Transmitters User's Guide",
  "doc_number": "M211399EN-H",
  "revision_date": "2016-04",
  "url": "https://docs.vaisala.com/api/khub/documents/Nz9Rxwoq_FgzXgpFHM~8Yw/content"
 },
 "integration": {
  "summary": "Set the protocol, baud rate and MAC address on the DIP switches, give the transmitter a unique device instance, then read relative humidity (AI 2) and temperature (AI 3), plus dewpoint (AI 4) or enthalpy (AI 10) if the control sequence needs them. Write the site altitude (AV 2) once for accurate calculated values.",
  "minimum_points": [
   {
    "ref": "AI 2",
    "name": "RH",
    "why": "Relative humidity, %"
   },
   {
    "ref": "AI 3",
    "name": "T",
    "why": "Temperature"
   },
   {
    "ref": "AI 4",
    "name": "Td",
    "why": "Dewpoint"
   },
   {
    "ref": "AI 10",
    "name": "h",
    "why": "Enthalpy"
   }
  ],
  "enable": null,
  "heartbeat": null,
  "remote_sensors": "AV 1 (operating pressure, hPa) or AV 2 (altitude) can be written by the BMS for the humidity calculations; the two are linked.",
  "setup": [
   "BACnet MS/TP on RS-485. DIP switches select the protocol (BACnet or Modbus) and baud rate: Automatic (default), 9600, 19200, 38400, 57600, 76800 or 115200.",
   "MAC address 0-255 on the 8-way address DIP switch; below 128 the transmitter is an MS/TP master, 128 and up a slave.",
   "The device instance is set to a unique value at the factory; change it, the device name, description, location and Max_Master with the BACNET service-port command.",
   "With automatic baud the transmitter listens 10 s at each rate and locks to the first valid traffic until reset or power cycle."
  ],
  "gotchas": [
   "Baud rate 4800 is not available with BACnet.",
   "OPER P and OPER Altitude are linked; write only one of them (writing one updates the other)."
  ]
 },
 "points": [
  {
   "type": "AI",
   "instance": 2,
   "name": "RH",
   "description": "Relative humidity",
   "units": "%RH",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 3,
   "name": "T",
   "description": "Temperature",
   "units": "°C or °F",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 4,
   "name": "Td",
   "description": "Dewpoint",
   "units": "°C or °F",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 5,
   "name": "Tdf",
   "description": "Dewpoint",
   "units": "°C or °F",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 6,
   "name": "dTd",
   "description": "Dewpoint depression",
   "units": "K or °F (delta)",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 7,
   "name": "Tw",
   "description": "Wet bulb temperature",
   "units": "°C or °F",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 8,
   "name": "a",
   "description": "Absolute humidity",
   "units": "g/m³ or gr/ft³",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 9,
   "name": "x",
   "description": "Mixing ratio",
   "units": "g/kg or gr/lb",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 10,
   "name": "h",
   "description": "Enthalpy",
   "units": "kJ/kg or BTU/lb",
   "access": "R",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 1,
   "name": "OPER P",
   "description": "Operating pressure for humidity calculations, default 1013.25",
   "units": "hPa",
   "access": "W",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 2,
   "name": "OPER Altitude",
   "description": "Operating altitude; linked to OPER P",
   "units": "m or ft",
   "access": "W",
   "states": ""
  }
 ],
 "page": "https://easybacnet.com/bacnet-points-lists/vaisala/hmw90",
 "note": "Provided as-is. Point availability varies by firmware and options; verify against the live device.",
 "disclaimer": "DISCLAIMER: reference only, provided AS IS with no warranty. May contain errors or be out of date. You must verify every point against the manufacturer's current documentation and the live device before use. easybacnet.com accepts no liability for its use and is not affiliated with the manufacturer. Terms: https://easybacnet.com/terms#content"
}