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Constant volume terminal unit controller · BACnet points list

Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) BACnet points list

Updated 28 October 2026

Short answer

Application 6662 runs a constant volume terminal box with up to three stages of electric heat on a Siemens BACnet PTEC controller over BACnet MS/TP. The flow loop holds OCC FLOW when occupied and UNOCC FLOW when unoccupied, and the heating loop runs the heat stages to hold room temperature. There is no automatic heat/cool switchover; PPCL or the field panel commands HEAT.COOL to pick the seasonal setpoints.

This page lists 81 BACnet objects for the Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) — 67 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 PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat)
Equipment
Constant volume terminal unit controller
Equipment type
VAV boxes & fan coils
BACnet objects
81 (67 writable)
Transport
BACnet MS/TP
Firmware
Newer than revision Bx40
Also known as
PTEC 6662, Application 6662, App 6662, 550-498PA, Siemens constant volume electric reheat
Source document
BACnet PTEC Controller Constant Volume with Electric Reheat, Application 6662, Application Note · 140-1108 · rev. 2014-10-27
Download CSV 81 rows Download EDE B.I.G.-EU JSON Manufacturer PDF ↗ Download Easy BACnet Mobile App Google Play

BMS integration notes: Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat)

Integration in brief

Address the controller on the BACnet MS/TP trunk (manually or with auto addressing), then release the box to application control. The BMS commands occupancy with OCC.UNOCC (BO 29), sets heat/cool mode with HEAT.COOL (BO 5) for the season, writes the occupied setpoints, and reads room temperature, airflow, heat stage 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 29OCC.UNOCCOCC = occupied, UNOCC = unoccupiedCommand
BO 5HEAT.COOLSeasonal HEAT/COOL; no automatic switchoverCommand
AO 6OCC CLG STPTOccupied cooling setpoint, °FCommand
AO 7OCC HTG STPTOccupied heating setpoint, °FCommand
AI 4ROOM TEMPSpace temperatureRead
AI 35AIR VOLUMEMeasured box airflow, cfmRead
BO 43HEAT STAGE 1Electric heat stage 1 on/offCommand
AO 99ERROR STATUSController error codeCommand

Enable & remote start

Occupancy is OCC.UNOCC (BO 29). With a wall switch on DI 2 and WALL SWITCH (BO 18) = YES, the switch sets it; standalone with no switch the controller stays occupied; on a network the field panel or BMS commands OCC.UNOCC. UNOCC OVRD (BO 21) shows a temporary occupied override from the room unit button.

Sensors & values from the BMS

PPCL or the field panel must command HEAT.COOL (BO 5) for seasonal switchover; the electric heat holds room temperature at the active setpoint in either mode.

Network setup

Watch out for

Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) 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.

81 of 81 shown
Type
Access
Show
Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) BACnet Points List
DescriptionStates
AO1CTLR ADDRESSController MS/TP addressCommand
AO2APPLICATIONApplication number running in the controllerCommand
AImin4ROOM TEMPRoom temperature from the room unit°FRead
BOmin5HEAT.COOLCurrent heating/cooling modeCommand0=COOL, 1=HEAT
AOmin6OCC CLG STPTOccupied cooling setpoint°FCommand
AOmin7OCC HTG STPTOccupied heating setpoint°FCommand
AO8UOC CLG STPTUnoccupied cooling setpoint°FCommand
AO9UOC HTG STPTUnoccupied heating setpoint°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 AI5Auxiliary temperature input on AI 5°FRead
BO18WALL SWITCHWall switch connected to DI 2Command0=NO, 1=YES
BI19DI OVRD SWRoom unit night override buttonRead0=OFF, 1=ON
AO20OVRD TIMENight override durationhCommand
BO21UNOCC OVRDUnoccupied override status (room unit button)Command0=OCC, 1=UNOCC
BI24DI 2Digital input 2Read0=OFF, 1=ON
BI25DI 3Digital input 3Read0=OFF, 1=ON
BOmin29OCC.UNOCCOccupied/unoccupied modeCommand0=OCC, 1=UNOCC
AO31UNOCC FLOWConstant airflow setpoint, unoccupiedcfmCommand
AO32OCC FLOWConstant airflow setpoint, occupiedcfmCommand
AImin35AIR VOLUMEMeasured airflowcfmRead
AO36FLOW COEFFAirflow pickup correction coefficientCommand
BO40FAIL MODEDamper position if the air velocity sensor failsCommand0=OPEN, 1=CLOSED
BO41DO 1Digital output 1Command0=OFF, 1=ON
BO42DO 2Digital output 2Command0=OFF, 1=ON
BOmin43HEAT STAGE 1Electric heat stage 1 outputCommand0=OFF, 1=ON
BO44HEAT STAGE 2Electric heat stage 2 outputCommand0=OFF, 1=ON
BO45HEAT STAGE 3Electric heat stage 3 outputCommand0=OFF, 1=ON
BO46DO 6Digital output 6Command0=OFF, 1=ON
BO47DO 7Digital output 7Command0=OFF, 1=ON
AO48DMPR COMDDamper position command%Command
AO49DMPR POSDamper position (calculated)%Command
BO50DO 8Digital output 8Command0=OFF, 1=ON
AO51MTR1 TIMINGMotor 1 full-stroke timesCommand
AO56DPR1 ROT ANGDamper 1 rotation angleCommand
AO58MTR SETUPMotor enable/reverse setup (additive code)Command
AO59DO DIR. REVDigital output direction reverse (additive code)Command
AO60EHEAT FLOWAirflow % needed before electric heat may run%Command
AO67HTG P GAINHeating loop proportional gainCommand
AO68HTG I GAINHeating loop integral gainCommand
AO69HTG D GAINHeating loop derivative gainCommand
AO70HTG BIASHeating loop bias%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
AO78CTL TEMPTemperature the controller is controlling to°FCommand
AO80HTG LOOPOUTHeating loop output%Command
AO81AVG HEAT OUTAverage auxiliary heat output%Command
AO82STAGE MAXStaged heat maximum, percent%Command
AO83STAGE MINStaged heat minimum, percent%Command
BO87CAL MODULECalibration module installedCommand0=NO, 1=YES
AO88STAGE COUNTNumber of electric heat stagesCommand
AO89STAGE TIMEElectric heat cycle timeminCommand
AO91TOTAL VOLUMETotal air volumeft³Command
AO92CTL STPTActive control setpoint°FCommand
AO93FLOW STPTAirflow setpoint, percent%Command
BO94CAL AIRStart air velocity sensor calibrationCommand0=NO, 1=YES
AO95CAL SETUPCalibration setup codeCommand
AO96CAL TIMERHours between automatic calibrationshCommand
AO97DUCT AREAInlet duct area for airflow calculationft²Command
AO98LOOP TIMEControl loop intervalsCommand
AOmin99ERROR STATUSController error status codeCommand
AO102AOV 1Analog output 1 (0-10 V)VCommand
AO103AOV 2Analog output 2 (0-10 V)VCommand
AO104AOV 3Analog output 3 (0-10 V)VCommand
AI105AI 3Spare analog input 3%Read
AI106AI 4Spare analog input 4°FRead
AO107RMTMP OFFSETRoom temperature calibration offset°FCommand
BI108DI 4Digital input 4Read0=OFF, 1=ON
BI109DI 5Digital input 5Read0=OFF, 1=ON
BI110DI 6Digital input 6Read0=OFF, 1=ON
AO111STPT SPANRoom unit setpoint adjustment span°FCommand
AO121DEW POINTRoom dew point°FCommand
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 PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) 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 PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat)

How many BACnet points does the Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) have?

This list has 81 BACnet objects: 8 analog inputs, 50 analog outputs, 6 binary inputs, 17 binary outputs. The exact set on a given unit depends on its firmware, installed options and configuration.

Which Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) BACnet points are writable?

67 of the 81 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 PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat) BACnet documentation?

The source is BACnet PTEC Controller Constant Volume with Electric Reheat, Application 6662, Application Note (140-1108), revision 2014-10-27, published free by Siemens at https://sid.siemens.com/api/khub/documents/PST6TEXgJdFgmH99XSL08Q/content.

What are the minimum BACnet points to integrate the Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat)?

Start with BO 29 OCC.UNOCC (OCC = occupied, UNOCC = unoccupied); BO 5 HEAT.COOL (Seasonal HEAT/COOL; no automatic switchover); AO 6 OCC CLG STPT (Occupied cooling setpoint, °F); AO 7 OCC HTG STPT (Occupied heating setpoint, °F); AI 4 ROOM TEMP (Space temperature); AI 35 AIR VOLUME (Measured box airflow, cfm); BO 43 HEAT STAGE 1 (Electric heat stage 1 on/off); AO 99 ERROR STATUS (Controller error code).

How do I enable BMS control of the Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat)?

Occupancy is OCC.UNOCC (BO 29). With a wall switch on DI 2 and WALL SWITCH (BO 18) = YES, the switch sets it; standalone with no switch the controller stays occupied; on a network the field panel or BMS commands OCC.UNOCC. UNOCC OVRD (BO 21) shows a temporary occupied override from the room unit button.

Can the BMS supply sensor values to the Siemens BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat)?

PPCL or the field panel must command HEAT.COOL (BO 5) for seasonal switchover; the electric heat holds room temperature at the active setpoint in either mode.

How do I check these points on the real BACnet PTEC Constant Volume Controller - Application 6662 (Constant Volume with Electric Heat)?

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 PTEC Controller Constant Volume with Electric Reheat, Application 6662, Application Note · 140-1108 · rev. 2014-10-27. Object names, instances and units are reproduced as published; descriptions are our own.