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Air handling / make-up air unit controller (heating, cooling, ventilation) · BACnet points list
Engineered Air C-TRAC3 Controller BACnet points list
Updated 6 November 2026
C-TRAC3 is Engineered Air's configurable unit controller. It supports BACnet MS/TP (9600-76.8k baud) and BACnet IP. The EMS can switch the unit on and off, write the primary and secondary discharge air setpoints and the minimum damper position, start dehumidification and disable the economizer, cooling or heating. It reports temperatures, blower, cooling and heating status, damper position, lockouts, terminal inputs and alarms.
This page lists 46 BACnet objects for the Engineered Air C-TRAC3 Controller — 9 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from Engineered Air’s own free documentation, linked below.
- Manufacturer
- Engineered Air
- Model
- C-TRAC3 Controller
- Equipment
- Air handling / make-up air unit controller (heating, cooling, ventilation)
- Equipment type
- Rooftop units, AHUs & DOAS
- BACnet objects
- 46 (9 writable)
- Transport
- BACnet MS/TP, BACnet IP
- Firmware
- Not stated
- Default device instance
- 77077
- Also known as
- C-TRAC3, CTRAC3, C-TRAC 3, EngA C-TRAC3
- Source document
- C-TRAC3 Communication Manual for BACnet · rev. May 23 R2
Reference only, provided as-is: verify against Engineered Air’s current documentation and the live device before use. Not official Engineered Air information. Terms of use.
BMS integration notes: Engineered Air C-TRAC3 Controller
Set the BACnet MS/TP or IP parameters on the PGD1 display (Networking > BMS Configurations) and cycle power. Command the unit with BV 42, write the discharge setpoint to AV 25 and the minimum damper position to AV 66, and read back AV 26 and the actual setpoint AV 14. Monitor blower status, discharge temperature, heating and cooling status and the alarm BVs.
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.
| Object | Name | Why | Access |
|---|---|---|---|
| BV 42 | EMS Unit Command On/Off | Unit on/off command (1 = on) | Write |
| AV 25 | EMS Discharge Air Setpoint | Discharge air setpoint (write-only), 0-255 °F | Write |
| AV 66 | EMS Damper Minimum Position Setpoint | Minimum OA damper position, 0-100 % | Write |
| AV 1044 | Unit On/Off Status | Unit on/off status | Read |
| BV 10 | Blower Status | Blower running | Read |
| AV 12 | Discharge Air Temperature | Discharge air temperature | Read |
| AV 14 | Discharge Air Temperature Setpoint | Active discharge setpoint | Read |
| BV 36 | Air Flow Problem | Airflow alarm | Read |
| BV 35 | Sensor Failure Alarm | Any temperature sensor failed | Read |
| BV 41 | Heat Fail Lockout | Heating failure lockout | Read |
Enable & remote start
BV 42 EMS Unit Command On/Off switches the unit (0 = off, 1 = on). With EMS control enabled the discharge setpoint equals the EMS setpoint. For night heat or morning warm-up the manual has the head end disable the economizer, set minimum position 0 %, set the discharge setpoint and enable the unit.
Network setup
- Defaults: device instance 77077; MS/TP baud 38400, address 77, Max Master 127, Max Info Frames 20.
- BACnet IP defaults: IP 172.16.0.1, UDP port 47808 (fixed).
- Settings are on the PGD1 display under Networking > BMS Configurations (password); change No to Yes to update, then cycle power.
- Connect the network before powering the controller so the network card comes up.
Watch out for
- Writes are held in RAM and lost on power loss unless saved with BV 49 Write to Flash; flash has limited write cycles, so don't save cyclically.
- Economizer, cooling and heating enables are inverted: Off = enabled.
- Read the setpoint back on AV 26, not AV 25.
Engineered Air C-TRAC3 Controller 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.
| Description | States | |||||
|---|---|---|---|---|---|---|
| AV | 7 | Damper Minimum Position | Required minimum damper position | % | Read | |
| AV | 10 | VFD Speed Feedback | % | Read | ||
| AV | 11 | Ambient Temperature | Read | |||
| AVmin | 12 | Discharge Air Temperature | Read | |||
| AV | 13 | Secondary Discharge Air Temperature | Multi-use sensor (secondary discharge, room, return...) | Read | ||
| AVmin | 14 | Discharge Air Temperature Setpoint | Active discharge setpoint after resets | Read | ||
| AV | 17 | Cooling Stages % On | % | Read | ||
| AV | 18 | Cooling Modulated Output | % | Read | ||
| AV | 19 | Damper % Open | Economizer output position (linearized) | % | Read | |
| AV | 20 | Heating Modulating % Output | % | Read | ||
| AVmin | 25 | EMS Discharge Air Setpoint | EMS discharge setpoint (write), 0-255 °F | Write | ||
| AV | 26 | EMS Discharge Air Setpoint | EMS discharge setpoint (read back) | Read | ||
| AV | 27 | EMS Secondary Discharge Air Setpoint | EMS secondary discharge setpoint (write) | Write | ||
| AV | 28 | EMS Secondary Discharge Air Setpoint | EMS secondary discharge setpoint (read back) | Read | ||
| AVmin | 66 | EMS Damper Minimum Position Setpoint | % | Write | ||
| AVmin | 1044 | Unit On/Off Status | Read | |||
| BV | 4 | Occupied Mode - FS | 24 Vac input FS, occupied | Read | On/Off | |
| BV | 5 | Cooling Mode – Terminal A | 24 Vac input A disabling cooling | Read | On/Off | |
| BV | 6 | Economizer Mode - E | 24 Vac input E disabling economizer | Read | On/Off | |
| BV | 7 | Heating Mode - HS | 24 Vac input HS disabling heating | Read | On/Off | |
| BV | 8 | Unoccupied Mode - K | 24 Vac input K, unoccupied / dehumidification call | Read | Enable/Disable | |
| BVmin | 10 | Blower Status | Read | On/Off | ||
| BV | 11 | Damper Override Low Discharge Temperature | Read | On/Off | ||
| BV | 13 | Cooling Lockout – Low Ambient Temperature | Read | On/Off | ||
| BV | 14 | External Cooling Lockout - A | Read | On/Off | ||
| BV | 15 | Economizer Mode | Read | On/Off | ||
| BV | 16 | Damper Contact DM closed | Read | On/Off | ||
| BV | 17 | Economizer At Minimum Due to High Ambient | Read | On/Off | ||
| BV | 18 | VFD Cooling Lockout – Limit Stages due to Low Air Volume | Read | On/Off | ||
| BV | 19 | Discharge Air Low Limit Lockout | Read | On/Off | ||
| BV | 23 | LMK or HE Failure Alarm | Loss of heat: LMK (electric) or HE (direct fired) safety | Read | On/Off | |
| BV | 24 | Discharge Air Sensor Alarm | Read | On/Off | ||
| BV | 25 | Secondary Discharge Air Sensor Alarm | Read | On/Off | ||
| BV | 26 | Ambient Sensor Alarm | Read | On/Off | ||
| BVmin | 35 | Sensor Failure Alarm | Read | On/Off | ||
| BVmin | 36 | Air Flow Problem | Airflow or VFD feedback seen before SA contact closed | Read | On/Off | |
| BV | 39 | Heating Status | Read | On/Off | ||
| BV | 40 | Heating Lockout High Ambient Temperature | Read | On/Off | ||
| BVmin | 41 | Heat Fail Lockout | Read | On/Off | ||
| BVmin | 42 | EMS Unit Command On/Off | Unit on/off command | Write | 0=Off, 1=On | |
| BV | 43 | EMS Dehumidification Enabled | Start dehumidification | Write | 0=No dehumidification, 1=Start dehumidification | |
| BV | 45 | EMS Economizer Enabled | Economizer enable (off = enabled) | Write | Off=Economizer enabled | |
| BV | 47 | EMS Cooling Enabled | Cooling enable (off = enabled) | Write | Off=Cooling enabled | |
| BV | 48 | EMS Heating Enabled | Heating enable (off = enabled) | Write | Off=Heating enabled | |
| BV | 49 | Write to Flash | Save RAM values to flash (limited write cycles) | Write | On/Off | |
| BV | 50 | Cooling Status – Mechanical Cooling On/Off | Read | On/Off |
No points match these filters.
Object ID lookup: Engineered Air C-TRAC3 Controller point IDs by name
AV7Damper Minimum PositionAV10VFD Speed FeedbackAV11Ambient TemperatureAV12Discharge Air TemperatureAV13Secondary Discharge Air TemperatureAV14Discharge Air Temperature SetpointAV17Cooling Stages % OnAV18Cooling Modulated OutputAV19Damper % OpenAV20Heating Modulating % OutputAV25EMS Discharge Air SetpointAV26EMS Discharge Air SetpointAV27EMS Secondary Discharge Air SetpointAV28EMS Secondary Discharge Air SetpointAV66EMS Damper Minimum Position SetpointAV1044Unit On/Off StatusBV4Occupied Mode - FSBV5Cooling Mode – Terminal ABV6Economizer Mode - EBV7Heating Mode - HSBV8Unoccupied Mode - KBV10Blower StatusBV11Damper Override Low Discharge TemperatureBV13Cooling Lockout – Low Ambient TemperatureBV14External Cooling Lockout - ABV15Economizer ModeBV16Damper Contact DM closedBV17Economizer At Minimum Due to High AmbientBV18VFD Cooling Lockout – Limit Stages due to Low Air VolumeBV19Discharge Air Low Limit LockoutBV23LMK or HE Failure AlarmBV24Discharge Air Sensor AlarmBV25Secondary Discharge Air Sensor AlarmBV26Ambient Sensor AlarmBV35Sensor Failure AlarmBV36Air Flow ProblemBV39Heating StatusBV40Heating Lockout High Ambient TemperatureBV41Heat Fail LockoutBV42EMS Unit Command On/OffBV43EMS Dehumidification EnabledBV45EMS Economizer EnabledBV47EMS Cooling EnabledBV48EMS Heating EnabledBV49Write to FlashBV50Cooling Status – Mechanical Cooling On/Off
Integration notes
- The manual gives a descriptive label for each object rather than an Object_Name string; the labels are used as names here.
- The discharge setpoint is written to AV 25 (write-only) and read back on AV 26; the secondary setpoint likewise uses AV 27 / AV 28.
- Temperatures read in °F or °C, chosen in the SERVICE menu on the PGD1 display.
- For the economizer, cooling and heating enables, Off means the function is enabled.
- Extra CRD I/O (BI-1 to BI-8, ID-1 to ID-14, Y-1 to Y-4, C-1 to C-13) maps to further AV/BV objects listed by terminal only; their names are on the unit's electrical data sheet, so they are not listed here.
- Source: C-TRAC3 Variable Description Table, page 14 (46 objects).
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 C-TRAC3 Controller 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 Engineered Air C-TRAC3 Controller
How many BACnet points does the Engineered Air C-TRAC3 Controller have?
This list has 46 BACnet objects: 16 analog values, 30 binary values. The exact set on a given unit depends on its firmware, installed options and configuration.
Which Engineered Air C-TRAC3 Controller BACnet points are writable?
9 of the 46 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.
Where is the official Engineered Air C-TRAC3 Controller BACnet documentation?
The source is C-TRAC3 Communication Manual for BACnet, revision May 23 R2, published free by Engineered Air at https://www.engineeredair.com/wp-content/uploads/2024/11/enga_ctrac3_bacnet_manual_may_23_r2.pdf.
What are the minimum BACnet points to integrate the Engineered Air C-TRAC3 Controller?
Start with BV 42 EMS Unit Command On/Off (Unit on/off command (1 = on)); AV 25 EMS Discharge Air Setpoint (Discharge air setpoint (write-only), 0-255 °F); AV 66 EMS Damper Minimum Position Setpoint (Minimum OA damper position, 0-100 %); AV 1044 Unit On/Off Status (Unit on/off status); BV 10 Blower Status (Blower running); AV 12 Discharge Air Temperature (Discharge air temperature); AV 14 Discharge Air Temperature Setpoint (Active discharge setpoint); BV 36 Air Flow Problem (Airflow alarm); BV 35 Sensor Failure Alarm (Any temperature sensor failed); BV 41 Heat Fail Lockout (Heating failure lockout).
How do I enable BMS control of the Engineered Air C-TRAC3 Controller?
BV 42 EMS Unit Command On/Off switches the unit (0 = off, 1 = on). With EMS control enabled the discharge setpoint equals the EMS setpoint. For night heat or morning warm-up the manual has the head end disable the economizer, set minimum position 0 %, set the discharge setpoint and enable the unit.
How do I check these points on the real C-TRAC3 Controller?
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 Engineered Air BACnet points lists
- Air handling / make-up air unit controller (I/O and expansion modules)
Engineered Air CenCon Controller and Expansion Modules (I/O devices)
Engineered Air appliances (air handlers, make-up air, indirect and direct gas-fired heaters, DX and energy recovery units) built with the CenCon controller, version 3.0.0 or later.
Also known as: CenCon, IOM65, C_XM, J_XM, G_XM, M_XM, ER_XM, S_XM, XP_XM, H_XM, CD_XM, P_XM, EngA CenCon - Air handling / make-up air unit controller (BMS command points)
Engineered Air CenCon_SW EMS Command Device (CenCon controller)
Engineered Air appliances (air handlers, make-up air, indirect and direct gas-fired heaters, DX and energy recovery units) built with the CenCon controller, version 3.0.0 or later.
Also known as: CenCon, CenCon_SW, CenCon SW, IOM65, EngA CenCon
Source: C-TRAC3 Communication Manual for BACnet · rev. May 23 R2. Object names, instances and units are reproduced as published; descriptions are our own.