{
 "manufacturer": "Siemens",
 "manufacturer_slug": "siemens",
 "model": "BACnet Programmable Fume Hood Controller - Application 6740 (2-Position Constant Volume with Damper)",
 "model_slug": "fume-hood-6740-two-position-constant-volume-damper",
 "short_model": "Fume Hood Controller 6740",
 "aliases": [
  "Application 6740",
  "App 6740",
  "Siemens fume hood controller",
  "Siemens FHC",
  "two-position fume hood",
  "constant volume fume hood"
 ],
 "equipment_type": "Laboratory VAV controller (fume hood)",
 "applies_to": "Constant volume or two-position fume hoods with an exhaust damper on a manifolded exhaust system, run by the Siemens BACnet programmable fume hood controller with an operator display panel.",
 "summary": "Application 6740 runs a constant volume or two-position fume hood on a Siemens BACnet programmable fume hood controller over BACnet MS/TP. It modulates the hood exhaust damper to hold a high or low exhaust airflow setpoint (EXH HI STPT / EXH LO STPT), picked by DI 2 or the left display button. It raises low/high flow warnings and alarms against the setpoint, has an emergency purge mode, and sends a 1-10 V exhaust flow signal on AO 2.",
 "bacnet_transport": [
  "BACnet MS/TP"
 ],
 "firmware": null,
 "default_device_instance": null,
 "access_inferred": true,
 "notes": [
  "AI and BI objects are read-only. AO and BO objects are BACnet output objects with a priority array; the guide has no access column, so access is inferred from object type. Many AOs are calculated status values, not commands.",
  "Instances shown in braces in the guide may be unbundled at a field panel; that marking is not reproduced here.",
  "Units are given in US units (cfm, ft², inH2O); the guide also lists SI factory defaults.",
  "The high setpoint is used if either DI2 STPT SW (BI 37) or ODP STPT SW (BO 22) is HI; both must be LO for the low setpoint.",
  "STARTUP MODE (AO 21): 0 = normal, 1 and 2 = decommission modes, 3 = start-up with alarms off (factory default).",
  "Alarm and warning limits (AO 10-13) are percentages of the active exhaust setpoint.",
  "The point table lists a binary output named DI 4 (BO 56); it is kept as printed."
 ],
 "source": {
  "title": "BACnet Programmable Fume Hood Controller 2-Position Constant Volume with Damper, Application 6740, Application Note",
  "doc_number": "140-1341",
  "revision_date": "2015-11-09",
  "url": "https://sid.siemens.com/api/khub/documents/LFSSQ8f~mpjer3CY5qEURw/content"
 },
 "integration": {
  "summary": "Address the controller on the BACnet MS/TP trunk (manually or with auto addressing) and set STARTUP MODE to normal. The BMS can select high or low flow with ODP STPT SW (BO 22), adjust the two exhaust setpoints, and reads exhaust airflow, the active setpoint and the alarm points.",
  "minimum_points": [
   {
    "ref": "BO 22",
    "name": "ODP STPT SW",
    "why": "HI = high exhaust setpoint (also set by DI 2)"
   },
   {
    "ref": "AO 80",
    "name": "EXH HI STPT",
    "why": "High exhaust airflow setpoint, cfm"
   },
   {
    "ref": "AO 81",
    "name": "EXH LO STPT",
    "why": "Low exhaust airflow setpoint, cfm"
   },
   {
    "ref": "AI 31",
    "name": "EXH VOL",
    "why": "Measured hood exhaust airflow, cfm"
   },
   {
    "ref": "AO 82",
    "name": "EXH STPT",
    "why": "Active exhaust airflow setpoint, cfm"
   },
   {
    "ref": "BO 5",
    "name": "LOW ALM",
    "why": "Low flow alarm"
   },
   {
    "ref": "BO 6",
    "name": "HIGH ALM",
    "why": "High flow alarm"
   },
   {
    "ref": "BO 7",
    "name": "EMER ALM",
    "why": "Emergency purge alarm"
   },
   {
    "ref": "BO 8",
    "name": "GEN FAILURE",
    "why": "General failure (sensor or hardware)"
   }
  ],
  "enable": "No enable point: the controller runs its sequence once STARTUP MODE (AO 21) is 0. The flow setpoint is high when DI 2 or the left display button (ODP STPT SW, BO 22) is HI.",
  "heartbeat": null,
  "remote_sensors": null,
  "setup": [
   "BACnet MS/TP only. CTLR ADDRESS (AO 1) holds the MS/TP address; the point table lists its factory value as 99.",
   "APPLICATION (AO 2) holds the application number; the point table lists its factory default as 6700."
  ],
  "gotchas": [
   "STARTUP MODE (AO 21) ships at 3 (start-up: control works but alarms are off and the display shows Startup). Set it to 0 for normal operation; 1 and 2 are decommission modes.",
   "Emergency purge from the display button (or DI 6) overrides all other control: EMER ALM is set at BACnet priority 1, the damper opens fully for EMER TIMER, then flow holds at EXH STPT times the EMER STPT percentage until the button is pressed again.",
   "If the controller loses power, the exhaust damper goes fully open.",
   "With a digital room unit (revision 26 and later), a command sent through the room unit puts the matching BACnet input Out Of Service.",
   "Loop gains, duct and sash dimensions, calibration and display settings are commissioning values; don't write them from the BMS routinely."
  ]
 },
 "points": [
  {
   "type": "AO",
   "instance": 1,
   "name": "CTLR ADDRESS",
   "description": "Controller MS/TP address",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 2,
   "name": "APPLICATION",
   "description": "Application number running in the controller",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 5,
   "name": "LOW ALM",
   "description": "Low flow alarm",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 6,
   "name": "HIGH ALM",
   "description": "High flow alarm",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 7,
   "name": "EMER ALM",
   "description": "Emergency purge alarm",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 8,
   "name": "GEN FAILURE",
   "description": "General failure (sensor or hardware)",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AO",
   "instance": 10,
   "name": "HI ALM LMT",
   "description": "High flow alarm limit, % of setpoint",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 11,
   "name": "HI WARN LMT",
   "description": "High flow warning limit, % of setpoint",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 12,
   "name": "LOW WARN LMT",
   "description": "Low flow warning limit, % of setpoint",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 13,
   "name": "LOW ALM LMT",
   "description": "Low flow alarm limit, % of setpoint",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 14,
   "name": "EMER TIMER",
   "description": "Emergency full-open time",
   "units": "s",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 15,
   "name": "EMER STPT",
   "description": "Emergency flow, % of the exhaust setpoint",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 16,
   "name": "LOW WARN",
   "description": "Low flow warning",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 17,
   "name": "HIGH WARN",
   "description": "High flow warning",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AO",
   "instance": 18,
   "name": "ALARM TIME",
   "description": "Delay before a warning or alarm is set",
   "units": "s",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 19,
   "name": "ALM AKNLG",
   "description": "Alarm silenced from the display panel",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 20,
   "name": "OCC.UNOCC",
   "description": "Occupied/unoccupied mode",
   "units": "",
   "access": "C",
   "states": "0=OCC, 1=UNOCC"
  },
  {
   "type": "AO",
   "instance": 21,
   "name": "STARTUP MODE",
   "description": "Normal, decommission or startup mode (code)",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 22,
   "name": "ODP STPT SW",
   "description": "High/low flow select from the display button",
   "units": "",
   "access": "C",
   "states": "0=HI, 1=LO"
  },
  {
   "type": "BO",
   "instance": 23,
   "name": "RIGHT SWITCH",
   "description": "Right display panel button",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AI",
   "instance": 31,
   "name": "EXH VOL",
   "description": "Measured hood exhaust airflow",
   "units": "cfm",
   "access": "R",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 32,
   "name": "FLOW COEF",
   "description": "Airflow pickup coefficient",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 33,
   "name": "DUCT AREA",
   "description": "Exhaust duct area",
   "units": "ft²",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 34,
   "name": "TRANS RANGE",
   "description": "Pressure transmitter range",
   "units": "inH2O",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 35,
   "name": "LINEAR FL RG",
   "description": "Range of a linear flow input",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 36,
   "name": "AVS2 PRESS",
   "description": "Air velocity sensor 2 pressure",
   "units": "inH2O",
   "access": "R",
   "states": ""
  },
  {
   "type": "BI",
   "instance": 37,
   "name": "DI2 STPT SW",
   "description": "High/low flow select input on DI 2",
   "units": "",
   "access": "R",
   "states": "0=HI, 1=LO"
  },
  {
   "type": "BI",
   "instance": 38,
   "name": "DI 6",
   "description": "Digital input 6",
   "units": "",
   "access": "R",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AO",
   "instance": 39,
   "name": "AO 1",
   "description": "Analog output 1",
   "units": "V",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 40,
   "name": "AO 3",
   "description": "Analog output 3",
   "units": "V",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 41,
   "name": "EXTN DO1",
   "description": "Damper actuator extend output on DO 1",
   "units": "",
   "access": "C",
   "states": "0=HOLD, 1=EXTN"
  },
  {
   "type": "BO",
   "instance": 42,
   "name": "RETC DO2",
   "description": "Damper actuator retract output on DO 2",
   "units": "",
   "access": "C",
   "states": "0=RETC, 1=HOLD"
  },
  {
   "type": "BO",
   "instance": 43,
   "name": "DO 3",
   "description": "Digital output 3",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 44,
   "name": "DO 4",
   "description": "Digital output 4",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 45,
   "name": "HI.LOW DO5",
   "description": "High/low flow status output on DO 5",
   "units": "",
   "access": "C",
   "states": "0=HI, 1=LO"
  },
  {
   "type": "BO",
   "instance": 46,
   "name": "DECOM DO6",
   "description": "Decommission output on DO 6",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 47,
   "name": "ALARM DO7",
   "description": "Local alarm output on DO 7",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 48,
   "name": "AUTOZERO DO8",
   "description": "Autozero module output on DO 8",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AI",
   "instance": 49,
   "name": "AI 3",
   "description": "Spare analog input 3",
   "units": "V",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 50,
   "name": "AI 4",
   "description": "Spare analog input 4",
   "units": "V",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 51,
   "name": "AI 5",
   "description": "Spare analog input 5",
   "units": "kΩ",
   "access": "R",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 56,
   "name": "DI 4",
   "description": "Binary output listed as DI 4 in the point table",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AO",
   "instance": 58,
   "name": "DMPR CMD",
   "description": "Exhaust damper drive command (-100 to 100)",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 59,
   "name": "INVERT DO2",
   "description": "Invert the DO 2 output",
   "units": "",
   "access": "C",
   "states": "0=NO, 1=YES"
  },
  {
   "type": "BO",
   "instance": 60,
   "name": "AVS FAILMODE",
   "description": "Damper action if the air velocity sensor fails",
   "units": "",
   "access": "C",
   "states": "0=HOLD, 1=OPEN"
  },
  {
   "type": "AO",
   "instance": 61,
   "name": "EXH P GAIN",
   "description": "Exhaust flow loop proportional gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 62,
   "name": "EXH I GAIN",
   "description": "Exhaust flow loop integral gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 63,
   "name": "EXH D GAIN",
   "description": "Exhaust flow loop derivative gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 78,
   "name": "STARTUP DI4",
   "description": "Startup mode input on DI 4",
   "units": "",
   "access": "C",
   "states": "0=NO, 1=YES"
  },
  {
   "type": "AO",
   "instance": 80,
   "name": "EXH HI STPT",
   "description": "High exhaust flow setpoint",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 81,
   "name": "EXH LO STPT",
   "description": "Low exhaust flow setpoint",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 82,
   "name": "EXH STPT",
   "description": "Active exhaust airflow setpoint",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 89,
   "name": "EXH SIG AO2",
   "description": "Exhaust flow signal out on AO 2",
   "units": "V",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 90,
   "name": "AO2 RANGE",
   "description": "Exhaust flow at 10 V on AO 2",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 91,
   "name": "AO2 DEADBAND",
   "description": "Deadband for the AO 2 flow signal",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 92,
   "name": "AO2 V MIN",
   "description": "Minimum AO 2 output voltage",
   "units": "V",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 94,
   "name": "CAL AIR",
   "description": "Start air velocity sensor calibration",
   "units": "",
   "access": "C",
   "states": "0=NO, 1=YES"
  },
  {
   "type": "AO",
   "instance": 95,
   "name": "CAL SETUP",
   "description": "Calibration setup code",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 96,
   "name": "CAL TIMER",
   "description": "Hours between automatic calibrations",
   "units": "h",
   "access": "C",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 97,
   "name": "AVS1 PRESS",
   "description": "Air velocity sensor 1 pressure",
   "units": "inH2O",
   "access": "R",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 98,
   "name": "LOOP TIME",
   "description": "Control loop interval",
   "units": "s",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 99,
   "name": "ERROR STATUS",
   "description": "Controller error status code",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 106,
   "name": "DISPLAY WT",
   "description": "Display smoothing weight",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 107,
   "name": "DISPLAY RES",
   "description": "Change needed to update the display",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 108,
   "name": "BLANK DSPLY",
   "description": "Blank the operator display panel",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 109,
   "name": "LAMP TEST",
   "description": "Test the display lamps",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 110,
   "name": "ENG UNITS",
   "description": "Display in English or SI units",
   "units": "",
   "access": "C",
   "states": "0=ENG, 1=SI"
  },
  {
   "type": "AO",
   "instance": 121,
   "name": "HI LIMIT",
   "description": "Feedback loop high limit (not described in the guide)",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 122,
   "name": "LO LIMIT",
   "description": "Feedback loop low limit (not described in the guide)",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 123,
   "name": "EMER DI6",
   "description": "Remote emergency purge input on DI 6",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 125,
   "name": "ODP DISPLAY",
   "description": "Display shows airflow or mode",
   "units": "",
   "access": "C",
   "states": "0=MODE, 1=CFM"
  },
  {
   "type": "AO",
   "instance": 126,
   "name": "AVE EXH VOL",
   "description": "Averaged exhaust airflow shown on the display",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 127,
   "name": "PPCL STATE",
   "description": "PPCL program loaded or empty",
   "units": "",
   "access": "C",
   "states": "0=EMPTY, 1=LOADED"
  }
 ],
 "page": "https://easybacnet.com/bacnet-points-lists/siemens/fume-hood-6740-two-position-constant-volume-damper",
 "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"
}