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Fan-powered VAV terminal unit controller · BACnet points list

Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) BACnet points list

Updated 28 October 2026

Short answer

Application 6635 controls a series 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 series fan runs all day; at night it starts when the valve opens past STAGE FAN or supply airflow rises past SERIES ON.

This page lists 90 BACnet objects for the Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) — 80 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from Siemens’s own free documentation, linked below.

Manufacturer
Siemens
Model
BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat)
Equipment
Fan-powered VAV terminal unit controller
Equipment type
VAV boxes & fan coils
BACnet objects
90 (80 writable)
Transport
BACnet MS/TP
Firmware
Not stated
Also known as
ATEC 6635, Application 6635, App 6635, 550-430PA, 550-431PA
Source document
BACnet ATEC Controller VAV - with Series Fan or Parallel Fan and Hot Water Reheat, Application 6635/6637, Application Note · 140-1215 · rev. 2017-12-12
Download CSV 90 rows Download EDE B.I.G.-EU JSON Manufacturer PDF ↗ Download Easy BACnet Mobile App Google Play

BMS integration notes: Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat)

Integration in brief

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 to map

The short list most integrators start with — enough to run the unit from a BMS. Map more as the job needs.

ObjectNameWhyAccess
BO 29DAY.NGTDAY = occupied, NIGHT = unoccupiedCommand
AO 6DAY CLG STPTOccupied cooling setpoint, °FCommand
AO 7DAY HTG STPTOccupied heating setpoint, °FCommand
BO 5HEAT.COOLCurrent mode: HEAT or COOLCommand
BO 46FANSeries fan on/offCommand
AI 4ROOM TEMPSpace temperatureRead
AI 35AIR VOLUMEMeasured primary airflow, cfmRead
AO 49DMPR POSPrimary air damper position, %Command
AO 53VLV POSHot water valve position, %Command
AO 99ERROR STATUSController error codeCommand

Enable & remote start

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.

Sensors & values from the BMS

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.

Network setup

Watch out for

Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) BACnet objects

Type: AI, AO, AV, BI, BO, BV, MI/MO/MV (multi-state) · Access: Read read-only, Write writable, Command writable with a priority array.

Note: the source document has no read/write column, so access here is inferred from the object type (inputs read-only, values writable). Confirm on the live controller before writing.

90 of 90 shown
Type
Access
Show
Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) BACnet Points List
DescriptionStates
AO1CTLR ADDRESSController MS/TP addressCommand
AO2APPLICATIONApplication number running in the controllerCommand
AO3RMTMP OFFSETRoom temperature calibration offset°FCommand
AImin4ROOM TEMPRoom temperature from the room unit°FRead
BOmin5HEAT.COOLCurrent heating/cooling modeCommand0=COOL, 1=HEAT
AOmin6DAY CLG STPTDay (occupied) cooling setpoint°FCommand
AOmin7DAY HTG STPTDay (occupied) heating setpoint°FCommand
AO8NGT CLG STPTNight (unoccupied) cooling setpoint°FCommand
AO9NGT HTG STPTNight (unoccupied) heating setpoint°FCommand
AO10DEW POINTRoom dew point°FCommand
AO11RM STPT MINLowest setpoint allowed from the room unit°FCommand
AO12RM STPT MAXHighest setpoint allowed from the room unit°FCommand
AI13RM STPT DIALSetpoint from the room unit dial or keypad°FRead
BO14STPT DIALUse the room unit setpoint dialCommand0=NO, 1=YES
AI15AUX TEMP AI3Spare temperature input on AI 3°FRead
AO16FLOW STARTHeating loop % where airflow starts to rise%Command
AO17FLOW ENDHeating loop % where airflow reaches maximum%Command
BO18WALL SWITCHUse a wall switch on AI/DI 4 for day/nightCommand0=NO, 1=YES
BI19DI OVRD SWRoom unit night override buttonRead0=OFF, 1=ON
AO20OVRD TIMENight override durationhCommand
BO21NGT OVRDNight override statusCommand0=DAY, 1=NIGHT
AO22REHEAT STARTHeating loop % where reheat starts%Command
AO23REHEAT ENDHeating loop % where reheat is at full output%Command
BI24DI 4Digital input 4Read0=OFF, 1=ON
BI25DI 3Digital input 3Read0=OFF, 1=ON
AO26SERIES ONNight: FLOW % above which the series fan starts%Command
AO27SERIES OFFNight: FLOW % below which the series fan may stop%Command
BOmin29DAY.NGTDay/night (occupancy) modeCommand0=DAY, 1=NIGHT
AO31CLG FLOW MINMinimum airflow in coolingcfmCommand
AO32CLG FLOW MAXMaximum airflow in coolingcfmCommand
AO33HTG FLOW MINMinimum airflow in heatingcfmCommand
AO34HTG FLOW MAXMaximum airflow in heatingcfmCommand
AImin35AIR VOLUMEMeasured airflowcfmRead
AO36FLOW COEFFFlow coefficient (box sizing value)Command
AO40NGT FLOW MINMinimum airflow at nightcfmCommand
BO41DO 1Digital output 1Command0=OFF, 1=ON
BO42DO 2Digital output 2Command0=OFF, 1=ON
BO43DO 3Digital output 3Command0=OFF, 1=ON
BO44DO 4Digital output 4Command0=OFF, 1=ON
BO45DO 5Digital output 5Command0=OFF, 1=ON
BOmin46FANFan commandCommand0=OFF, 1=ON
AO47VENT DMD MINVentilation demand minimum airflowcfmCommand
AO48DMPR COMDDamper position command%Command
AOmin49DMPR POSDamper position%Command
AI50AI 4Spare temperature input on AI 4°FRead
AO51MTR1 TIMINGMotor 1 full-stroke timesCommand
AO52VLV COMDHot water valve command%Command
AOmin53VLV POSHot water valve position%Command
AO54STPT SPANRoom unit setpoint adjustment span°FCommand
AO55MTR2 TIMINGMotor 2 full-stroke timesCommand
AO56DMPR ROT ANGDamper rotation angleCommand
AO58MTR SETUPMotor setup codeCommand
AO59DO DIR. REVDigital output direction reverse settingCommand
AO63CLG P GAINCooling loop proportional gainCommand
AO64CLG I GAINCooling loop integral gainCommand
AO65CLG D GAINCooling loop derivative gainCommand
BO66CHK OUTStart the built-in checkout (fault detection) routineCommand0=NO, 1=YES
AO67HTG P GAINHeating loop proportional gainCommand
AO68HTG I GAINHeating loop integral gainCommand
AO69HTG D GAINHeating loop derivative gainCommand
AO70CHK STATUSCheckout result code (additive; -1 = not run)Command
AO71FLOW P GAINFlow loop proportional gainCommand
AO72FLOW I GAINFlow loop integral gainCommand
AO73FLOW D GAINFlow loop derivative gainCommand
AO74FLOW BIASFlow loop bias%Command
AO75FLOWAirflow as percent of maximum%Command
AO76CTL FLOW MINActive minimum airflowcfmCommand
AO77CTL FLOW MAXActive maximum airflowcfmCommand
AO78CTL TEMPTemperature the controller is controlling to°FCommand
AO79CLG LOOPOUTCooling loop output%Command
AO80HTG LOOPOUTHeating loop output%Command
AO83STAGE FANValve opening above which the fan may start%Command
AO84AOV 1Analog output 1 (0-10 V)VCommand
AO85SWITCH LIMITLoop output below which mode may switch%Command
AO86SWITCH TIMEMinimum time before heat/cool switchoverminCommand
AO90SWITCH DBANDTemperature deadband for heat/cool switchover°FCommand
AO92CTL STPTActive control setpoint°FCommand
AO93FLOW STPTAirflow setpoint, percent%Command
BO94CAL AIRStart air velocity sensor calibrationCommand0=NO, 1=YES
AO95CAL SETUPCalibration setup codeCommand
AO96CAL TIMERCalibration timerhCommand
AO97DUCT AREAInlet duct area for airflow calculationft²Command
AO98LOOP TIMEControl loop intervalsCommand
AOmin99ERROR STATUSController error status codeCommand
AO102AOV 1 CLOSEAO1 output voltage for valve closedVCommand
AO103AOV 1 OPENAO1 output voltage for valve fully openVCommand
AO124SENSOR SELRoom unit / sensor select code (additive)Command
AI125RM CO2Room CO2ppmRead
AI126RM RHRoom relative humidity%Read
BO127PPCL STATEPPCL program loaded or emptyCommand0=EMPTY, 1=LOADED

Integration notes

Check it against the live device. A points list tells you what the controller can expose; the unit in front of you may differ by firmware or installed options. Easy BACnet scans a network for BACnet IP devices from an Android phone, reads every object on the BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) and exports what it actually has to Excel — free. New to BACnet? Start with what a BACnet points list is and what the object types mean.

Questions about the Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat)

How many BACnet points does the Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) have?

This list has 90 BACnet objects: 7 analog inputs, 66 analog outputs, 3 binary inputs, 14 binary outputs. The exact set on a given unit depends on its firmware, installed options and configuration.

Which Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) BACnet points are writable?

80 of the 90 objects accept a write. Points marked Command have a priority array: a write holds until it is released, so release it back to automatic when you are done. The source has no read/write column, so this is inferred from object type.

Where is the official Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat) BACnet documentation?

The source is BACnet ATEC Controller VAV - with Series Fan or Parallel Fan and Hot Water Reheat, Application 6635/6637, Application Note (140-1215), revision 2017-12-12, published free by Siemens at https://sid.siemens.com/api/khub/documents/Jd3lP9netS6yp6U_8BzABA/content.

What are the minimum BACnet points to integrate the Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat)?

Start with BO 29 DAY.NGT (DAY = occupied, NIGHT = unoccupied); AO 6 DAY CLG STPT (Occupied cooling setpoint, °F); AO 7 DAY HTG STPT (Occupied heating setpoint, °F); BO 5 HEAT.COOL (Current mode: HEAT or COOL); BO 46 FAN (Series fan on/off); AI 4 ROOM TEMP (Space temperature); AI 35 AIR VOLUME (Measured primary airflow, cfm); AO 49 DMPR POS (Primary air damper position, %); AO 53 VLV POS (Hot water valve position, %); AO 99 ERROR STATUS (Controller error code).

How do I enable BMS control of the Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat)?

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.

Can the BMS supply sensor values to the Siemens BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat)?

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.

How do I check these points on the real BACnet ATEC VAV Controller - Application 6635 (Series Fan with Hot Water Reheat)?

Scan the network with a BACnet IP browser such as Easy BACnet, open the device and compare its object list with this table. Anything missing is usually an option that isn't installed or a point that is disabled in the controller's configuration.

More Siemens BACnet points lists

Source: BACnet ATEC Controller VAV - with Series Fan or Parallel Fan and Hot Water Reheat, Application 6635/6637, Application Note · 140-1215 · rev. 2017-12-12. Object names, instances and units are reproduced as published; descriptions are our own.