{
 "manufacturer": "Siemens",
 "manufacturer_slug": "siemens",
 "model": "BACnet ATEC VAV Controller - Application 6637 (Parallel Fan with Hot Water Reheat)",
 "model_slug": "atec-6637-vav-parallel-fan-hot-water",
 "short_model": "ATEC Parallel Fan VAV 6637",
 "aliases": [
  "ATEC 6637",
  "Application 6637",
  "App 6637",
  "550-430PA",
  "550-431PA"
 ],
 "equipment_type": "Fan-powered VAV terminal unit controller",
 "applies_to": "Parallel fan-powered VAV boxes with a hot water reheat valve on the Siemens BACnet ATEC controller (550-430PA / 550-431PA).",
 "summary": "Application 6637 controls a parallel fan-powered VAV box with hot water reheat on a Siemens BACnet ATEC controller over BACnet MS/TP. The damper modulates for cooling and the heating loop modulates the hot water valve (floating on DO 3/DO 4 or 0-10 V on analog output AO1 (AOV 1, AO 84)). The fan is off in cooling; in heating it runs when the valve is open past STAGE FAN and supply airflow is below PARALLEL ON.",
 "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 (°F, cfm, ft²); the guide also lists SI factory defaults.",
  "The ATEC is the Siemens VAV controller with the damper actuator built in (550-430PA 44 lb-in or 550-431PA 88 lb-in).",
  "The series fan version is application 6635 in the same guide; its table has SERIES ON/OFF instead of PARALLEL ON/OFF.",
  "The fan is on DO 6 (BO 46). AOV 1 OPEN and AOV 1 CLOSE (AO 103/102) set the voltages for a 0-10 V valve on the AO1 hardware output (AOV 1, AO 84)."
 ],
 "source": {
  "title": "BACnet ATEC Controller VAV - with Series Fan or Parallel Fan and Hot Water Reheat, Application 6635/6637, Application Note",
  "doc_number": "140-1215",
  "revision_date": "2017-12-12",
  "url": "https://sid.siemens.com/api/khub/documents/Jd3lP9netS6yp6U_8BzABA/content"
 },
 "integration": {
  "summary": "Give the controller its MS/TP address (CTLR ADDRESS, or Auto Addressing) and configure the valve output. The BMS commands occupancy with DAY.NGT (BO 29) and the day setpoints, and reads room temperature, airflow, damper and valve position, fan status and the error status.",
  "minimum_points": [
   {
    "ref": "BO 29",
    "name": "DAY.NGT",
    "why": "DAY = occupied, NIGHT = unoccupied"
   },
   {
    "ref": "AO 6",
    "name": "DAY CLG STPT",
    "why": "Occupied cooling setpoint, °F"
   },
   {
    "ref": "AO 7",
    "name": "DAY HTG STPT",
    "why": "Occupied heating setpoint, °F"
   },
   {
    "ref": "BO 5",
    "name": "HEAT.COOL",
    "why": "Current mode: HEAT or COOL"
   },
   {
    "ref": "BO 46",
    "name": "FAN",
    "why": "Parallel fan on/off"
   },
   {
    "ref": "AI 4",
    "name": "ROOM TEMP",
    "why": "Space temperature"
   },
   {
    "ref": "AI 35",
    "name": "AIR VOLUME",
    "why": "Measured primary airflow, cfm"
   },
   {
    "ref": "AO 49",
    "name": "DMPR POS",
    "why": "Primary air damper position, %"
   },
   {
    "ref": "AO 53",
    "name": "VLV POS",
    "why": "Hot water valve position, %"
   },
   {
    "ref": "AO 99",
    "name": "ERROR STATUS",
    "why": "Controller error code"
   }
  ],
  "enable": "Occupancy is DAY.NGT (BO 29). With a wall switch on AI/DI 4 and WALL SWITCH (BO 18) = YES, the switch sets it; with WALL SWITCH = NO a standalone controller stays in day mode, and on a network the field panel can command DAY.NGT. NGT OVRD (BO 21) shows a temporary day override from the room unit button.",
  "heartbeat": null,
  "remote_sensors": "VENT DMD MIN (AO 47) can be reset by the field panel or PPCL (for example from CO2) to set the occupied ventilation minimum airflow; the larger of it and the cooling or heating minimum is used.",
  "setup": [
   "BACnet MS/TP only. CTLR ADDRESS (AO 1) holds the MS/TP address; the factory value is 255.",
   "APPLICATION (AO 2) shows the application number in the controller; the point table lists a factory value of 6684.",
   "Auto Discovery finds controllers on the MS/TP trunk by serial number; an unaddressed controller can be auto-addressed and detects the baud rate itself.",
   "If PPCL is loaded in the controller (PPCL STATE = LOADED), a new application number from 12000 to 12999 must be assigned."
  ],
  "gotchas": [
   "The guide states the controller, as shipped from the factory, keeps all connected equipment OFF.",
   "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, motor timing, rotation angles and setup codes are commissioning values; avoid writing them from the BMS routinely.",
   "If the air velocity sensor fails the box falls back to pressure-dependent damper control; if the room sensor fails it uses the last good value.",
   "The setup that runs the parallel fan only for low supply airflow is meant for coils in the discharge air; with coils in the return/plenum path it can damage them."
  ]
 },
 "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": "AO",
   "instance": 3,
   "name": "RMTMP OFFSET",
   "description": "Room temperature calibration offset",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 4,
   "name": "ROOM TEMP",
   "description": "Room temperature from the room unit",
   "units": "°F",
   "access": "R",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 5,
   "name": "HEAT.COOL",
   "description": "Current heating/cooling mode",
   "units": "",
   "access": "C",
   "states": "0=COOL, 1=HEAT"
  },
  {
   "type": "AO",
   "instance": 6,
   "name": "DAY CLG STPT",
   "description": "Day (occupied) cooling setpoint",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 7,
   "name": "DAY HTG STPT",
   "description": "Day (occupied) heating setpoint",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 8,
   "name": "NGT CLG STPT",
   "description": "Night (unoccupied) cooling setpoint",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 9,
   "name": "NGT HTG STPT",
   "description": "Night (unoccupied) heating setpoint",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 10,
   "name": "DEW POINT",
   "description": "Room dew point",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 11,
   "name": "RM STPT MIN",
   "description": "Lowest setpoint allowed from the room unit",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 12,
   "name": "RM STPT MAX",
   "description": "Highest setpoint allowed from the room unit",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 13,
   "name": "RM STPT DIAL",
   "description": "Setpoint from the room unit dial or keypad",
   "units": "°F",
   "access": "R",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 14,
   "name": "STPT DIAL",
   "description": "Use the room unit setpoint dial",
   "units": "",
   "access": "C",
   "states": "0=NO, 1=YES"
  },
  {
   "type": "AI",
   "instance": 15,
   "name": "AUX TEMP AI3",
   "description": "Spare temperature input on AI 3",
   "units": "°F",
   "access": "R",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 16,
   "name": "FLOW START",
   "description": "Heating loop % where airflow starts to rise",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 17,
   "name": "FLOW END",
   "description": "Heating loop % where airflow reaches maximum",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 18,
   "name": "WALL SWITCH",
   "description": "Use a wall switch on AI/DI 4 for day/night",
   "units": "",
   "access": "C",
   "states": "0=NO, 1=YES"
  },
  {
   "type": "BI",
   "instance": 19,
   "name": "DI OVRD SW",
   "description": "Room unit night override button",
   "units": "",
   "access": "R",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AO",
   "instance": 20,
   "name": "OVRD TIME",
   "description": "Night override duration",
   "units": "h",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 21,
   "name": "NGT OVRD",
   "description": "Night override status",
   "units": "",
   "access": "C",
   "states": "0=DAY, 1=NIGHT"
  },
  {
   "type": "AO",
   "instance": 22,
   "name": "REHEAT START",
   "description": "Heating loop % where reheat starts",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 23,
   "name": "REHEAT END",
   "description": "Heating loop % where reheat is at full output",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "BI",
   "instance": 24,
   "name": "DI 4",
   "description": "Digital input 4",
   "units": "",
   "access": "R",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BI",
   "instance": 25,
   "name": "DI 3",
   "description": "Digital input 3",
   "units": "",
   "access": "R",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AO",
   "instance": 28,
   "name": "PARALLEL ON",
   "description": "Heating: FLOW % below which the parallel fan may start",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 29,
   "name": "DAY.NGT",
   "description": "Day/night (occupancy) mode",
   "units": "",
   "access": "C",
   "states": "0=DAY, 1=NIGHT"
  },
  {
   "type": "AO",
   "instance": 30,
   "name": "PARALLEL OFF",
   "description": "Heating: FLOW % above which the parallel fan stops",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 31,
   "name": "CLG FLOW MIN",
   "description": "Minimum airflow in cooling",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 32,
   "name": "CLG FLOW MAX",
   "description": "Maximum airflow in cooling",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 33,
   "name": "HTG FLOW MIN",
   "description": "Minimum airflow in heating",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 34,
   "name": "HTG FLOW MAX",
   "description": "Maximum airflow in heating",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 35,
   "name": "AIR VOLUME",
   "description": "Measured airflow",
   "units": "cfm",
   "access": "R",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 36,
   "name": "FLOW COEFF",
   "description": "Flow coefficient (box sizing value)",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 40,
   "name": "NGT FLOW MIN",
   "description": "Minimum airflow at night",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 41,
   "name": "DO 1",
   "description": "Digital output 1",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 42,
   "name": "DO 2",
   "description": "Digital output 2",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "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": "DO 5",
   "description": "Digital output 5",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "BO",
   "instance": 46,
   "name": "FAN",
   "description": "Fan command",
   "units": "",
   "access": "C",
   "states": "0=OFF, 1=ON"
  },
  {
   "type": "AO",
   "instance": 47,
   "name": "VENT DMD MIN",
   "description": "Ventilation demand minimum airflow",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 48,
   "name": "DMPR COMD",
   "description": "Damper position command",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 49,
   "name": "DMPR POS",
   "description": "Damper position",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 50,
   "name": "AI 4",
   "description": "Spare temperature input on AI 4",
   "units": "°F",
   "access": "R",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 51,
   "name": "MTR1 TIMING",
   "description": "Motor 1 full-stroke time",
   "units": "s",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 52,
   "name": "VLV COMD",
   "description": "Hot water valve command",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 53,
   "name": "VLV POS",
   "description": "Hot water valve position",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 54,
   "name": "STPT SPAN",
   "description": "Room unit setpoint adjustment span",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 55,
   "name": "MTR2 TIMING",
   "description": "Motor 2 full-stroke time",
   "units": "s",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 56,
   "name": "DMPR ROT ANG",
   "description": "Damper rotation angle",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 58,
   "name": "MTR SETUP",
   "description": "Motor setup code",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 59,
   "name": "DO DIR. REV",
   "description": "Digital output direction reverse setting",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 63,
   "name": "CLG P GAIN",
   "description": "Cooling loop proportional gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 64,
   "name": "CLG I GAIN",
   "description": "Cooling loop integral gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 65,
   "name": "CLG D GAIN",
   "description": "Cooling loop derivative gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "BO",
   "instance": 66,
   "name": "CHK OUT",
   "description": "Start the built-in checkout (fault detection) routine",
   "units": "",
   "access": "C",
   "states": "0=NO, 1=YES"
  },
  {
   "type": "AO",
   "instance": 67,
   "name": "HTG P GAIN",
   "description": "Heating loop proportional gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 68,
   "name": "HTG I GAIN",
   "description": "Heating loop integral gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 69,
   "name": "HTG D GAIN",
   "description": "Heating loop derivative gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 70,
   "name": "CHK STATUS",
   "description": "Checkout result code (additive; -1 = not run)",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 71,
   "name": "FLOW P GAIN",
   "description": "Flow loop proportional gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 72,
   "name": "FLOW I GAIN",
   "description": "Flow loop integral gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 73,
   "name": "FLOW D GAIN",
   "description": "Flow loop derivative gain",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 74,
   "name": "FLOW BIAS",
   "description": "Flow loop bias",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 75,
   "name": "FLOW",
   "description": "Airflow as percent of maximum",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 76,
   "name": "CTL FLOW MIN",
   "description": "Active minimum airflow",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 77,
   "name": "CTL FLOW MAX",
   "description": "Active maximum airflow",
   "units": "cfm",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 78,
   "name": "CTL TEMP",
   "description": "Temperature the controller is controlling to",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 79,
   "name": "CLG LOOPOUT",
   "description": "Cooling loop output",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 80,
   "name": "HTG LOOPOUT",
   "description": "Heating loop output",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 83,
   "name": "STAGE FAN",
   "description": "Valve opening above which the fan may start",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 84,
   "name": "AOV 1",
   "description": "Analog output 1 (0-10 V)",
   "units": "V",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 85,
   "name": "SWITCH LIMIT",
   "description": "Loop output below which mode may switch",
   "units": "%",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 86,
   "name": "SWITCH TIME",
   "description": "Minimum time before heat/cool switchover",
   "units": "min",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 90,
   "name": "SWITCH DBAND",
   "description": "Temperature deadband for heat/cool switchover",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 92,
   "name": "CTL STPT",
   "description": "Active control setpoint",
   "units": "°F",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 93,
   "name": "FLOW STPT",
   "description": "Airflow setpoint, percent",
   "units": "%",
   "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": "Calibration timer",
   "units": "h",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 97,
   "name": "DUCT AREA",
   "description": "Inlet duct area for airflow calculation",
   "units": "ft²",
   "access": "C",
   "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": 102,
   "name": "AOV 1 CLOSE",
   "description": "AO1 output voltage for valve closed",
   "units": "V",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 103,
   "name": "AOV 1 OPEN",
   "description": "AO1 output voltage for valve fully open",
   "units": "V",
   "access": "C",
   "states": ""
  },
  {
   "type": "AO",
   "instance": 124,
   "name": "SENSOR SEL",
   "description": "Room unit / sensor select code (additive)",
   "units": "",
   "access": "C",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 125,
   "name": "RM CO2",
   "description": "Room CO2",
   "units": "ppm",
   "access": "R",
   "states": ""
  },
  {
   "type": "AI",
   "instance": 126,
   "name": "RM RH",
   "description": "Room relative humidity",
   "units": "%",
   "access": "R",
   "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/atec-6637-vav-parallel-fan-hot-water",
 "note": "Re-typed from the manufacturer's public documentation (see source). Point availability varies by firmware and options; verify against the live device."
}