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Make-up air heater / tempered air unit DDC controller · BACnet points list
CaptiveAire Direct Digital Controls (DDC) Heater Controller BACnet points list
Updated 6 November 2026
CaptiveAire's DDC controller runs a heater or tempered make-up air unit and talks BACnet MS/TP, Metasys N2, Modbus or LonWorks, chosen by DIP switches. The BMS picks the occupancy source, enables the unit through BV 1 when AV 1 = 2, writes heating and cooling setpoints, can call cooling stages directly and send VFD speed and damper signals. It reports intake, discharge and room temperatures, fan, damper, heat and cooling commands and status, and a set of alarm BVs (airflow, filter, freeze, heat failure, high/low supply air, smoke).
This page lists 59 BACnet objects for the CaptiveAire Direct Digital Controls (DDC) Heater Controller — 22 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from CaptiveAire’s own free documentation, linked below.
- Manufacturer
- CaptiveAire
- Model
- Direct Digital Controls (DDC) Heater Controller
- Equipment
- Make-up air heater / tempered air unit DDC controller
- Equipment type
- Rooftop units, AHUs & DOAS
- BACnet objects
- 59 (22 writable)
- Transport
- BACnet MS/TP
- Firmware
- Not stated
- Also known as
- A0020659, CaptiveAire DDC, DDC controller, ctrl_source
Reference only, provided as-is: verify against CaptiveAire’s current documentation and the live device before use. Not official CaptiveAire information. Terms of use.
BMS integration notes: CaptiveAire Direct Digital Controls (DDC) Heater Controller
Set the address on the two rotary switches (default 03) and check the protocol DIP switches are on BACnet MS/TP (factory baud 9600). Write AV 1 ctrl_source = 2 so BV 1 enable_bas runs the unit, then write the heating supply air setpoint AV 3. Monitor occupancy status, supply fan status, discharge temperature, heat command 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 1 | enable_bas | Unoccupied/occupied (run) command from the BAS | Write |
| AV 1 | ctrl_source | Must be 2 for BV 1 BAS control | Write |
| AV 3 | hsat_stpt | Heating supply air setpoint, 40-140 °F | Write |
| AV 6 | cl_iat_stpt | Intake air temperature to start cooling | Write |
| BV 2 | occ_status | Occupancy status | Read |
| BV 4 | sf_status | Supply fan status (airflow proven) | Read |
| AV 9 | edat | Discharge air temperature | Read |
| BV 12 | ht_on_cmd | Call for heat relay on | Read |
| BV 31 | af_fail | Airflow failure alarm | Read |
| BV 37 | ht_fail | Heating failure alarm | Read |
Enable & remote start
AV 1 ctrl_source picks the occupancy method: 0 digital input, 1 keypad, 2 BAS using BV 1, 3 BACnet schedule, 4 override on. With AV 1 = 2, BV 1 enable_bas switches the unit between unoccupied and occupied. BV 15 emerg_alm_in = On shuts the unit down.
Sensors & values from the BMS
AV 13 vfd_spd_in and AV 15 mod_dmp_in take a network voltage for the VFD speed and modulating damper; BV 8 and BV 10 let the network call cooling stages directly, subject to the unit's safeties.
Network setup
- Protocol (BACnet MS/TP, N2, Modbus or LonWorks) is set at the factory on DIP switches 3-4; switches 1-2 set the baud (factory 9600).
- Address is set on two rotary switches (tens and ones), factory default 03; power cycle after changing it.
- BACnet MS/TP connects to the RS-485 port at the upper left of the controller.
Watch out for
- BV 15 is a network emergency stop: On shuts the unit down.
- Cooling stage requests (BV 8, BV 10) still need fan status, heating off and the intake lockouts satisfied.
- BV 38 alarms if a keypad override is left locked on.
CaptiveAire Direct Digital Controls (DDC) Heater 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 | |||||
|---|---|---|---|---|---|---|
| AVmin | 1 | ctrl_source | Software control source (occupancy method) | Write | 0=Digital input, 1=Keypad, 2=BAS via BV 1, 3=BACnet schedule, 4=Override on | |
| AV | 2 | iat_sensor_visible | Incoming Air Temperature Sensor; range -25.0 to 225.0 | °F | Read | |
| AVmin | 3 | hsat_stpt | Heating Supply Air Setpoint; range 40.0 to 140.0; default 55.0 | °F | Write | |
| AV | 4 | eht_stpt | Effective Heating Setpoint | °F | Read | |
| AV | 5 | ht_iat_stpt | Heating Intake Air Activation Setpoint; range 40.0 to 90.0; default 45.0 | °F | Write | |
| AVmin | 6 | cl_iat_stpt | Cooling Intake Air Setpoint; range 60.0 to 120.0; default 85.0 | °F | Write | |
| AV | 7 | ecl_stpt | Effective Cooling Setpoint | °F | Read | |
| AV | 8 | cl_s2_ofst | Cooling Stage 2 Offset; range 1.0 to 30.0 | °F | Write | |
| AVmin | 9 | edat | Effective Discharge Air Temperature; range -25.0 to 225.0 | °F | Read | |
| AV | 10 | s1_cl_dly | Cooling Stage 1 Off Delay; range 1 to 30; default 5 | min | Write | |
| AV | 11 | s2_cl_dly | Cooling Stage 2 On Delay; range 1 to 30; default 5 | min | Write | |
| AV | 12 | htg_vlv_out | Heating valve output (0 % low fire, 100 % high fire) | % | Read | |
| AV | 13 | vfd_spd_in | VFD Speed Input; range 0.0 to 10.0 | V | Write | |
| AV | 14 | vfd_spd_out | VFD Speed Output; range 0.0 to 10.0 | V | Read | |
| AV | 15 | mod_dmp_in | Modulating Damper Input; range 0.0 to 10.0 | V | Write | |
| AV | 16 | mod_dmp_out | Modulating Damper Output; range 0.0 to 10.0 | V | Read | |
| AV | 17 | rodt_heat_stpt | Heating Room Override Supply Air Setpoint; range 80.0 to 140.0; default 120.0 | °F | Write | |
| AV | 18 | cool_intake_lockout | Cooling Intake Air Low Temp Lockout; range 60.0 to 130.0; default 65.0 | °F | Write | |
| AV | 19 | heat_intake_lockout | Heating Intake Air High Temp Lockout; range 35.0 to 130.0; default 65.0 | °F | Write | |
| AV | 20 | rat_sensor_visible | Space (Room) Air Temperature Sensor; range -25.0 to 225.0 | °F | Read | |
| AV | 21 | rt_heat_stpt | Heating Room Temperature Setpoint; range 50.0 to 90.0; default 70.0 | °F | Write | |
| AV | 22 | rt_heat_stpt_diff | Heating Room Temperature Setpoint Differential; range 1.0 to 10.0; default 2.0 | °F | Write | |
| BV | 0 | hdwr_strt_toggle | Hardware Start Toggle | Write | ||
| BVmin | 1 | enable_bas | BV Unit Enable (BAS) | Write | ||
| BVmin | 2 | occ_status | Occupancy Status | Read | ||
| BV | 3 | sf_cmd | Supply Fan Command | Read | ||
| BVmin | 4 | sf_status | Supply Fan Status | Read | ||
| BV | 5 | af_sts | Airflow Proving Status | Read | ||
| BV | 6 | oad_cmd | Outside Air Damper Command | Read | ||
| BV | 7 | oad_sts | Outside Air Damper Status | Read | ||
| BV | 8 | s1_clg_on | 1st Stage Cooling On | Write | ||
| BV | 9 | s1_clg_cmd | 1st Stage Cooling Command | Read | ||
| BV | 10 | s2_clg_on | 2nd Stage Cooling On | Write | ||
| BV | 11 | s2_clg_cmd | 2nd Stage Cooling Command | Read | ||
| BVmin | 12 | ht_on_cmd | Heat On Command | Read | ||
| BV | 13 | fltr_sts | Clogged Filter Status | Read | On=Normal, Off=Clogged filter | |
| BV | 14 | smk_sts | Smoke Detector Status | Read | On=Smoke alarm | |
| BV | 15 | emerg_alm_in | Emergency Alarm | Write | ||
| BV | 16 | room_override | Room Override Status | Read | ||
| BV | 17 | heat_control | Heating Temperature Control | Write | Off=Discharge control, On=Space control | |
| BV | 18 | fst_toggle | Clogged Filter Toggle | Write | ||
| BV | 19 | smk_toggle | Smoke Detector Toggle | Write | ||
| BVmin | 31 | af_fail | AF_FAIL: Airflow Failure | Read | ||
| BV | 32 | clg_fltr | CLG_FLTR: Filter Change Required | Read | ||
| BV | 33 | clg_rntm | CLG_RNTM: Cooling Runtime Expired | Read | ||
| BV | 34 | csat_hi | CSAT_HI: High Cooling Supply Air Temperature | Read | ||
| BV | 35 | freeze | FREEZE: Freezestat | Read | ||
| BV | 36 | hsat_lo | HSAT_LO: Low Heating Supply Air Temperature | Read | ||
| BVmin | 37 | ht_fail | HT_FAIL: Heating Failure | Read | ||
| BV | 38 | key_out_lck | KEY_OUT_LCK: Keypad Output Locked | Read | ||
| BV | 39 | oad_fail | OAD_FAIL: Outside Air Damper Failure | Read | ||
| BV | 40 | oad_hand | OAD_HAND: Outside Air Damper In Hand | Read | ||
| BV | 41 | oad_rntm | OAD_RNTM: Outside Air Damper Runtime Expired | Read | ||
| BV | 42 | sat_hi | SAT_HI: High Supply Air Temperature | Read | ||
| BV | 43 | sat_lo | SAT_LO: Low Supply Air Temperature | Read | ||
| BV | 44 | sf_fail | SF_FAIL: Supply Fan Failure | Read | ||
| BV | 45 | sf_hand | SF_HAND: Supply Fan In Hand | Read | ||
| BV | 46 | sf_rntm | SF_RNTM: Supply Fan Runtime Expired | Read | ||
| BV | 47 | smoke | SMOKE: Smoke Detector Alarm | Read |
No points match these filters.
Object ID lookup: CaptiveAire Direct Digital Controls Heater Controller point IDs by name
AV1ctrl_sourceAV2iat_sensor_visibleAV3hsat_stptAV4eht_stptAV5ht_iat_stptAV6cl_iat_stptAV7ecl_stptAV8cl_s2_ofstAV9edatAV10s1_cl_dlyAV11s2_cl_dlyAV12htg_vlv_outAV13vfd_spd_inAV14vfd_spd_outAV15mod_dmp_inAV16mod_dmp_outAV17rodt_heat_stptAV18cool_intake_lockoutAV19heat_intake_lockoutAV20rat_sensor_visibleAV21rt_heat_stptAV22rt_heat_stpt_diffBV0hdwr_strt_toggleBV1enable_basBV2occ_statusBV3sf_cmdBV4sf_statusBV5af_stsBV6oad_cmdBV7oad_stsBV8s1_clg_onBV9s1_clg_cmdBV10s2_clg_onBV11s2_clg_cmdBV12ht_on_cmdBV13fltr_stsBV14smk_stsBV15emerg_alm_inBV16room_overrideBV17heat_controlBV18fst_toggleBV19smk_toggleBV31af_failBV32clg_fltrBV33clg_rntmBV34csat_hiBV35freezeBV36hsat_loBV37ht_failBV38key_out_lckBV39oad_failBV40oad_handBV41oad_rntmBV42sat_hiBV43sat_loBV44sf_failBV45sf_handBV46sf_rntmBV47smoke
Integration notes
- Names are the 'BACnet Reference' (or 'Network Reference') printed for each variable.
- Access follows the manual's 'Editable'/'On/Off Switch' versus 'Fixed readout' wording; the alarm BVs 31-47 are read-only.
- Temperatures are in °F by default and can be changed to °C in software.
- Several settings depend on others: BV 1 needs AV 1 = 2; BV 0 needs BV 19 = 0; BV 17 needs BV 18 = 0 (and BV 18 needs BV 17 = 0, as printed).
- AV 12 is printed with two different ranges (0-100 % and 1.0-10.0, default 2.0); only the percent range is used here.
- Source: List of Analog Variables, List of Binary Variables and Network Alarm Variables, manual pages 6-18 (59 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 Direct Digital Controls (DDC) Heater 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 CaptiveAire Direct Digital Controls (DDC) Heater Controller
How many BACnet points does the CaptiveAire Direct Digital Controls (DDC) Heater Controller have?
This list has 59 BACnet objects: 22 analog values, 37 binary values. The exact set on a given unit depends on its firmware, installed options and configuration.
Which CaptiveAire Direct Digital Controls (DDC) Heater Controller BACnet points are writable?
22 of the 59 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 CaptiveAire Direct Digital Controls (DDC) Heater Controller BACnet documentation?
The source is Direct Digital Controls (DDC) Installation, Operation, and Maintenance Manual (A0020659), revision February 2025 Rev. 7, published free by CaptiveAire at https://www.captiveaire.com/manuals/electrical/ddc-oim.pdf.
What are the minimum BACnet points to integrate the CaptiveAire Direct Digital Controls (DDC) Heater Controller?
Start with BV 1 enable_bas (Unoccupied/occupied (run) command from the BAS); AV 1 ctrl_source (Must be 2 for BV 1 BAS control); AV 3 hsat_stpt (Heating supply air setpoint, 40-140 °F); AV 6 cl_iat_stpt (Intake air temperature to start cooling); BV 2 occ_status (Occupancy status); BV 4 sf_status (Supply fan status (airflow proven)); AV 9 edat (Discharge air temperature); BV 12 ht_on_cmd (Call for heat relay on); BV 31 af_fail (Airflow failure alarm); BV 37 ht_fail (Heating failure alarm).
How do I enable BMS control of the CaptiveAire Direct Digital Controls (DDC) Heater Controller?
AV 1 ctrl_source picks the occupancy method: 0 digital input, 1 keypad, 2 BAS using BV 1, 3 BACnet schedule, 4 override on. With AV 1 = 2, BV 1 enable_bas switches the unit between unoccupied and occupied. BV 15 emerg_alm_in = On shuts the unit down.
Can the BMS supply sensor values to the CaptiveAire Direct Digital Controls (DDC) Heater Controller?
AV 13 vfd_spd_in and AV 15 mod_dmp_in take a network voltage for the VFD speed and modulating damper; BV 8 and BV 10 let the network call cooling stages directly, subject to the unit's safeties.
How do I check these points on the real Direct Digital Controls (DDC) Heater 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 CaptiveAire BACnet points lists
- Kitchen hood demand control ventilation (DCV) controller (exhaust and make-up air fans)
CaptiveAire DCV Package DDC (Protocessor BACnet)
CaptiveAire demand control ventilation packages that run kitchen hood exhaust and supply (make-up air) fans, with the factory BACnet option.
Also known as: CaptiveAire DCV, Demand Control Ventilation, DCV Packages Network, Kitchen hood DCV, CASlink, Protocessor, CN0861 - DOAS rooftop unit
CaptiveAire DOAS RTU Series packaged rooftop unit, legacy IBT controls (Protocessor BACnet)
CaptiveAire DOAS RTU Series packaged rooftop units built with the older IBT-based unit controls (listed as 'Paragon - IBT Controls (Legacy)').
Also known as: A0026936, CaptiveAire DOAS RTU, Paragon IBT controls (legacy), DOAS RTU Series, CaptiveAire DOAS, Protocessor - Kitchen hood exhaust / make-up air fan controller (demand control)
CaptiveAire EMSplus Kitchen Hood Exhaust Controls (BACnet IP)
CaptiveAire EMSplus kitchen ventilation control panels ordered with the BACnet IP communication option.
Also known as: EMSplus, EMS Plus, EMS+, A0017802, CaptiveAire EMSplus - HVLS / ventilation fan control panel (up to 10 fans)
CaptiveAire HVLS and General Ventilation Fan Control (ECPM03, Protocessor BACnet)
CaptiveAire HVLS and general ventilation fan control packages with the ECPM03 board and the factory Protocessor BACnet gateway.
Also known as: A0025729, CaptiveAire HVLS, HVLS fan control, High Volume Low Speed fan, ECPM03, CASlink HVLS, Protocessor - Lighting control panel (8 zones)
CaptiveAire Lighting Control System (ECPM03, Protocessor BACnet)
CaptiveAire Lighting Control System panels with the ECPM03 board and the factory Protocessor BACnet gateway.
Also known as: A0027767, Lighting Control System, ECPM03, CASlink lighting, CaptiveAire lighting control panel, Protocessor - Make-up air unit (indirect gas-fired heater)
CaptiveAire Modular Indirect Fired Heater (IBT controls, Protocessor BACnet)
CaptiveAire modular indirect-fired make-up air heaters, modules and furnace inserts run by the IBT controller with the optional Protocessor BACnet gateway.
Also known as: A0016988, IBT heater, IBT board, Indirect Fired Bent Tube, Modular Indirect Fired Heater, Indirect Fired Module, Indirect Fired Furnace, Protocessor - Make-up air unit controller
CaptiveAire MUA Heater DDC (Protocessor BACnet)
CaptiveAire make-up air heater units (including direct-fired) with the factory DDC/BMS package.
Also known as: CaptiveAire make-up air, Direct fired MUA, Tempered make-up air, DDC Application Guide MUA - Rooftop unit / DOAS controller
CaptiveAire Paragon RTU / DOAS DDC (Protocessor BACnet)
CaptiveAire Paragon HVAC series packaged rooftop units and dedicated outdoor air systems with the factory DDC package.
Also known as: Paragon, CaptiveAire DOAS, CaptiveAire RTU, Protocessor, CN0861, RTU DDC Points - Kitchen hood self-cleaning wash system control panel
CaptiveAire Self Cleaning System (SCS) Control Panel
CaptiveAire Self Cleaning System panels that hot-water wash or cold-water mist kitchen exhaust hoods and plenums, and can also run the hood's fan and light zones.
Also known as: CaptiveAire SCS, Self Cleaning System, Hood wash panel, Hot Water Wash, Cold Water Mist, ECPM03, Protocessor
Source: Direct Digital Controls (DDC) Installation, Operation, and Maintenance Manual · A0020659 · rev. February 2025 Rev. 7. Object names, instances and units are reproduced as published; descriptions are our own.