{
 "manufacturer": "Greystone Energy Systems",
 "manufacturer_slug": "greystone",
 "model": "CHT Series CO2 / RH / temperature sensor (BACnet MS/TP)",
 "model_slug": "cht-co2-rh-temperature-sensor",
 "aliases": [
  "CHT",
  "CHTDT",
  "CHTXXXBAC",
  "Greystone CHT"
 ],
 "equipment_type": "CO2 / RH / temperature sensor",
 "applies_to": "Greystone CHT series combined CO2, humidity and temperature sensors with the BACnet MS/TP output.",
 "summary": "The CHT is a Greystone CO2 sensor with optional RH and temperature, talking native BACnet MS/TP. Measurements are three Analog Inputs; relay setup, offsets and altitude are Analog Values, and units, auto-calibration and relay test are Binary Values. Objects for options that are not fitted report a fault.",
 "bacnet_transport": [
  "BACnet MS/TP"
 ],
 "firmware": "1.4 (PICS, June 13, 2022)",
 "default_device_instance": 381003,
 "access_inferred": false,
 "notes": [
  "Points from the object summary table and per-object pages of the setup guide.",
  "AI 2 and AI 3 need the RH and temperature options; the relay objects need the relay option.",
  "Multistate objects are Multi-State Values (MSV) in the guide; listed here as MV.",
  "Access from the PICS: Present_Value is writable on AV, BV and MSV objects."
 ],
 "source": {
  "title": "CO2/RH/T Sensor CHT Series - Setup Guide BACnet Communication",
  "doc_number": "SG-CHTXXXBAC-02",
  "revision_date": "04/22",
  "url": "https://downloads.greystoneenergy.com/SG/SG-CHTXXXBAC-002.pdf"
 },
 "integration": {
  "summary": "Set a unique MS/TP MAC and device instance in the menu, then read CO2 (AI 1) plus the RH and temperature inputs if fitted. AVs and BVs are setup values.",
  "minimum_points": [
   {
    "ref": "AI 1",
    "name": "CO2 Value",
    "why": "Space CO2, ppm"
   },
   {
    "ref": "AI 2",
    "name": "RH Value",
    "why": "Space RH (RH option)"
   },
   {
    "ref": "AI 3",
    "name": "Temperature Value",
    "why": "Space temperature (temperature option)"
   },
   {
    "ref": "BI 1",
    "name": "Relay Status",
    "why": "CO2 relay energized"
   }
  ],
  "enable": null,
  "heartbeat": null,
  "remote_sensors": null,
  "setup": [
   "Default MS/TP MAC address is 3 and default baud is 9600; both are set in the Setup menu.",
   "Device instance defaults to 381000 + MAC (381003); it stops following the MAC once written over BACnet.",
   "Lower Max_Master from 127 to the highest MAC on the segment to cut token-passing overhead."
  ],
  "gotchas": [
   "Objects for options that are not fitted report Reliability NO_SENSOR and Event_State FAULT; do not poll them.",
   "The sensor updates about every 4 s; poll every 5-10 s, not faster."
  ]
 },
 "points": [
  {
   "type": "AI",
   "instance": 1,
   "name": "CO2 Value",
   "description": "CO2 reading, 0-10,000 ppm",
   "units": "ppm",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 2,
   "name": "RH Value",
   "description": "Relative humidity (RH option)",
   "units": "%RH",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 3,
   "name": "Temperature Value",
   "description": "Temperature (temperature option); units follow BV 1",
   "units": "°F / °C",
   "access": "R",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 1,
   "name": "Relay Setpoint",
   "description": "CO2 relay trip point, 500-1500 ppm (default 1000)",
   "units": "ppm",
   "access": "W",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 2,
   "name": "Relay Hysteresis",
   "description": "Relay hysteresis, 25-200 ppm (default 50)",
   "units": "ppm",
   "access": "W",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 3,
   "name": "Relay ON Delay",
   "description": "Relay on delay, 0-255 s (default 15)",
   "units": "s",
   "access": "W",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 4,
   "name": "Temperature Offset",
   "description": "Temperature calibration offset (default 0)",
   "units": "delta °C / °F",
   "access": "W",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 5,
   "name": "RH Offset",
   "description": "RH calibration offset, -10 to 10 %RH",
   "units": "%RH",
   "access": "W",
   "states": ""
  },
  {
   "type": "AV",
   "instance": 6,
   "name": "Altitude",
   "description": "Installed altitude, 0-2550 m in 50 m steps",
   "units": "m",
   "access": "W",
   "states": ""
  },
  {
   "type": "BV",
   "instance": 1,
   "name": "Temperature Units",
   "description": "Temperature unit select",
   "units": "",
   "access": "W",
   "states": "0=°C, 1=°F"
  },
  {
   "type": "BV",
   "instance": 2,
   "name": "Auto Cal Enable",
   "description": "CO2 automatic calibration (default enabled)",
   "units": "",
   "access": "W",
   "states": "0=Disable, 1=Enable"
  },
  {
   "type": "BV",
   "instance": 3,
   "name": "Relay Test",
   "description": "Forces the relay for testing",
   "units": "",
   "access": "W",
   "states": "0=Relay off, 1=Relay on"
  },
  {
   "type": "BI",
   "instance": 1,
   "name": "Relay Status",
   "description": "CO2 relay energized",
   "units": "",
   "access": "R",
   "states": "0=Inactivated, 1=Activated"
  },
  {
   "type": "MV",
   "instance": 1,
   "name": "LCD Backlight",
   "description": "LCD backlight mode (default Auto)",
   "units": "",
   "access": "W",
   "states": "0=AUTO, 1=OFF, 2=ON"
  },
  {
   "type": "MV",
   "instance": 2,
   "name": "Display Modes",
   "description": "Values shown on the LCD",
   "units": "",
   "access": "W",
   "states": "0=CO2, 1=CO2+RH+T"
  }
 ],
 "page": "https://easybacnet.com/bacnet-points-lists/greystone/cht-co2-rh-temperature-sensor",
 "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"
}