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Fan coil unit controller · BACnet points list

Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) BACnet points list

Updated 6 November 2026

Short answer

Application 2542 runs a two-pipe fan coil unit on the older Siemens BACnet ASC (terminal equipment) controller over BACnet MS/TP. Valve 1 modulates for cooling or heating depending on the water in the pipe, an optional second valve adds heat in sequence, and the fan runs all day or cycles with valve demand (CYCLE FAN). Heat/cool mode follows the pipe temperature sensor (SUPPLY TEMP against COOL TEMP and HEAT TEMP) or a field panel command.

This page lists 61 BACnet objects for the Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) — 56 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
Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating)
Equipment
Fan coil unit controller
Equipment type
VAV boxes & fan coils
BACnet objects
61 (56 writable)
Transport
BACnet MS/TP
Firmware
Not stated
Also known as
Application 2542, App 2542, 550-433, Siemens BACnet ASC, Siemens two-pipe fan coil controller, BTEC
Source document
Two-Pipe Fan Coil BACnet ASC Controller, Application 2542 - Cooling or Heating, Application Notes · 140-0749 · rev. 2015-11
Download CSV 61 rows Download EDE B.I.G.-EU JSON Manufacturer PDF ↗ Compare with your scan Download Easy BACnet Mobile App Google Play

Reference only, provided as-is: verify against Siemens’s current documentation and the live device before use. Not official Siemens information. Terms of use.

BMS integration notes: Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating)

Integration in brief

Set the MS/TP address, then release the unit to application control. The BMS commands occupancy with DAY.NGT (BO 29) and the day setpoints and, without a pipe sensor, sets heat/cool through SUPPLY TEMP; it reads room temperature, fan status, valve position 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 46FANFan on/offCommand
AI 4ROOM TEMPSpace temperatureRead
AO 49VLV 1 POSValve 1 position, %Command
AO 99ERROR STATUSController error codeCommand

Enable & remote start

Occupancy is DAY.NGT (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 in day mode; on a network the field panel or BMS commands DAY.NGT. NGT OVRD (BO 21) shows a temporary night override from the room unit button.

Sensors & values from the BMS

Without a pipe sensor, the field panel commands SUPPLY TEMP (AI 15) below COOL TEMP for cooling or above HEAT TEMP for heating.

Network setup

Watch out for

Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) 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.

61 of 61 shown
Type
Access
Show
Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) BACnet Points List
DescriptionStates
AO1CLTR 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
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
AI15SUPPLY TEMPSupply pipe water temperature°FRead
AO16VLV 1 STARTHeating loop % where valve 1 starts to open%Command
AO17VLV 1 ENDHeating loop % where valve 1 is full open%Command
BO18WALL SWITCHWall switch connected to DI 2Command0=NO, 1=YES
BI19DI OVRD SWRoom unit night override buttonRead0=OFF, 1=ON
AO20OVRD TIMENight override durationhCommand
BO21NGT OVRDNight override statusCommand0=DAY, 1=NIGHT
AO22VLV 2 STARTHeating loop % where valve 2 starts to open%Command
AO23VLVL 2 ENDHeating loop % where valve 2 is full open%Command
BI24DI 2Digital input 2Read0=OFF, 1=ON
BOmin29DAY.NGTDay/night (occupancy) modeCommand0=DAY, 1=NIGHT
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
AO48VLV 1 COMDValve 1 command (heating or cooling)%Command
AOmin49VLV 1 POSValve 1 position (calculated)%Command
AO51MTR 1 TIMINGMotor 1 full-stroke timesCommand
AO52VLV 2 COMDValve 2 command (second heating valve)%Command
AO53VLV 2 POSValve 2 position (calculated)%Command
AO55MTR 2 TIMINGMotor 2 full-stroke timesCommand
AO56MTR 1 ROT ANGMotor 1 rotation angleCommand
AO57MTR 2 ROT ANGMotor 2 rotation angleCommand
AO58MTR SETUPMotor enable/reverse setup (additive code)Command
AO59DO DIR. REVDigital output direction reverse (additive code)Command
BO60CYCLE FANCycle the fan with demand in day modeCommand0=NO, 1=YES
AO61COOL TEMPPipe temperature below which the unit cools°FCommand
AO62HEAT TEMPPipe temperature above which the unit heats°FCommand
AO63CLG P GAINCooling loop proportional gainCommand
AO64CLG I GAINCooling loop integral gainCommand
AO65CLG D GAINCooling loop derivative gainCommand
AO66CLG BIASCooling loop bias%Command
AO67HTG P GAINHeating loop proportional gainCommand
AO68HTG I GAINHeating loop integral gainCommand
AO69HTG D GAINHeating loop derivative gainCommand
AO70HTG BIASHeating loop bias%Command
AO78CLT TEMPTemperature the controller is controlling to°FCommand
AO79CLG LOOPOUTCooling loop output%Command
AO80HTG LOOPOUTHeating loop output%Command
AO84STAGE FANValve opening that turns the fan on when cycling%Command
AO85SWITCH LIMITLoop output below which mode may switch%Command
AO88VALVE CNTNumber of heating valves (1 or 2)Command
AO92CTRL STPTActive control setpoint°FCommand
AO96CAL TIMERHours between automatic calibrationshCommand
AO98LOOP TIMEControl loop intervalsCommand
AOmin99ERROR STATUSController error status codeCommand
Object ID lookup: Siemens BACnet ASC Two-Pipe Fan Coil 2542 point IDs by name

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. This list is provided as-is for reference only and may contain mistakes — confirming it before you write, map or commission anything is up to you (terms). Easy BACnet scans a network for BACnet IP devices from an Android phone, reads every object on the Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) 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 Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating)

How many BACnet points does the Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) have?

This list has 61 BACnet objects: 3 analog inputs, 44 analog outputs, 2 binary inputs, 12 binary outputs. The exact set on a given unit depends on its firmware, installed options and configuration.

Which Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) BACnet points are writable?

56 of the 61 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 Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating) BACnet documentation?

The source is Two-Pipe Fan Coil BACnet ASC Controller, Application 2542 - Cooling or Heating, Application Notes (140-0749), revision 2015-11, published free by Siemens at https://sid.siemens.com/api/khub/documents/irhhDwnQMAlC4IiuqChI~g/content.

What are the minimum BACnet points to integrate the Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating)?

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 (Fan on/off); AI 4 ROOM TEMP (Space temperature); AO 49 VLV 1 POS (Valve 1 position, %); AO 99 ERROR STATUS (Controller error code).

How do I enable BMS control of the Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating)?

Occupancy is DAY.NGT (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 in day mode; on a network the field panel or BMS commands DAY.NGT. NGT OVRD (BO 21) shows a temporary night override from the room unit button.

Can the BMS supply sensor values to the Siemens Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating)?

Without a pipe sensor, the field panel commands SUPPLY TEMP (AI 15) below COOL TEMP for cooling or above HEAT TEMP for heating.

How do I check these points on the real Two-Pipe Fan Coil BACnet ASC Controller - Application 2542 (Cooling or Heating)?

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: Two-Pipe Fan Coil BACnet ASC Controller, Application 2542 - Cooling or Heating, Application Notes · 140-0749 · rev. 2015-11. Object names, instances and units are reproduced as published; descriptions are our own.