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BTU (energy) meter, clamp-on ultrasonic · BACnet points list
ONICON System-40 BTU Measurement System BACnet points list
Updated 4 November 2026
The System-40 measures flow with clamp-on ultrasonic transducers and pairs it with supply and return temperature sensors to calculate thermal energy. Over BACnet MS/TP it exposes energy and flow rates, temperatures, ultrasonic signal diagnostics, energy and volume totals, auxiliary pulse totals and a meter status code. Mode 1 and mode 2 totals are kept separately when the meter runs in dual mode.
This page lists 46 BACnet objects for the ONICON System-40 BTU Measurement System — 7 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from ONICON’s own free documentation, linked below.
- Manufacturer
- ONICON
- Model
- System-40 BTU Measurement System
- Equipment
- BTU (energy) meter, clamp-on ultrasonic
- Equipment type
- Thermostats, sensors & meters
- BACnet objects
- 46 (7 writable)
- Transport
- BACnet MS/TP
- Firmware
- Not stated
- Default device instance
- 57017
- Also known as
- System-40, System 40, System-40-BAC, ONICON System-40
Reference only, provided as-is: verify against ONICON’s current documentation and the live device before use. Not official ONICON information. Terms of use.
BMS integration notes: ONICON System-40 BTU Measurement System
Read the energy rate, flow and both temperatures for live data and the energy and volume totals for billing or trending. Map the signal quality AI and MV 1 Meter Status to catch transducer or sensor problems. Only the total resets are written from the BMS.
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 |
|---|---|---|---|
| AI 1 | Energy rate | Energy rate, kBtu/h by default | Read |
| AI 2 | Volume rate | Flow rate, gpm by default | Read |
| AI 3 | Supply temperature | Supply water temperature | Read |
| AI 4 | Return temperature | Return water temperature | Read |
| AV 1 | Mode 1 energy total | Energy total (mode 1 total in dual mode) | Read |
| AV 9 | Mode 1 volume total | Volume total (mode 1 total in dual mode) | Read |
| AI 7 | Signal quality | Ultrasonic signal quality, 3 = best | Read |
| MV 1 | Meter Status | Meter status; 1 = Normal, 11 = System Fault | Read |
Network setup
- BACnet MS/TP on terminal block TB4, 2-wire half duplex, 1/4 unit load.
- MAC address 1-127, default 17. Device instance 0-4,194,302, default 57017.
- Baud 9600, 19200, 38400 or 76800; default 38400. 120 ohm termination selectable, default off; no biasing.
Watch out for
- In dual mode read both the mode 1 and mode 2 totals (for example AV 1 and AV 2).
- The trend log multiple holds 120 records and rolls over; interval 30 s to 1 h, default 15 min.
- Meter Status 8 (Low Signal Quality) means a weak transducer signal; the manual says to check for air trapped in the piping.
ONICON System-40 BTU Measurement System 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.
| Description | States | |||||
|---|---|---|---|---|---|---|
| AImin | 1 | Energy rate | kBtu/h | Read | ||
| AImin | 2 | Volume rate | gpm | Read | ||
| AImin | 3 | Supply temperature | °F | Read | ||
| AImin | 4 | Return temperature | °F | Read | ||
| AI | 5 | Delta temperature | °F | Read | ||
| AI | 6 | Signal strength | Ultrasonic signal strength, 0-100 counts | Read | ||
| AImin | 7 | Signal quality | 3-31 counts, 3 = best | Read | ||
| AI | 8 | Speed of sound | Measured speed of sound in the fluid | ft/s | Read | |
| AI | 9 | Peak energy rate | Interval set by the trend log object | kBtu/h | Read | |
| AI | 10 | Average delta temp | Interval set by the trend log object | °F | Read | |
| AVmin | 1 | Mode 1 energy total | Single mode: Energy total | kBtu | Read | |
| AV | 2 | Mode 2 energy total | Single mode: Energy total | kBtu | Read | |
| AV | 3 | Y-T-D mode 1 energy total | Single mode: Y-T-D energy total | kBtu | Read | |
| AV | 4 | Y-T-D mode 2 energy total | Single mode: Y-T-D energy total | kBtu | Read | |
| AV | 5 | Previous Year mode 1 energy total | Single mode: Previous year energy total | kBtu | Read | |
| AV | 6 | Previous Year mode 2 energy total | Single mode: Previous year energy total | kBtu | Read | |
| AV | 7 | User mode 1 energy total | Single mode: User defined energy total | kBtu | Read | |
| AV | 8 | User mode 2 energy total | Single mode: User defined energy total | kBtu | Read | |
| AVmin | 9 | Mode 1 volume total | Single mode: Volume total | gal | Read | |
| AV | 10 | Mode 2 volume total | Single mode: Volume total | gal | Read | |
| AV | 11 | Y-T-D mode 1 volume total | Single mode: Y-T-D volume total | gal | Read | |
| AV | 12 | Y-T-D mode 2 volume total | Single mode: Y-T-D volume total | gal | Read | |
| AV | 13 | User mode 1 volume total | Single mode: User defined volume total | gal | Read | |
| AV | 14 | User mode 2 volume total | Single mode: User defined volume total | gal | Read | |
| AV | 15 | Aux pulse input 1 total | Single mode: Aux pulse input 1 total | Read | ||
| AV | 16 | Aux pulse input 2 total | Single mode: Aux pulse input 2 total | Read | ||
| AV | 17 | Aux pulse input 3 total | Single mode: Aux pulse input 3 total | Read | ||
| AV | 18 | Run hours | Single mode: Run hours | h | Read | |
| AV | 19 | Incremental energy total mode 1 | Single mode: Incremental energy total | kBtu | Read | |
| AV | 20 | Incremental energy total mode 2 | Single mode: Incremental energy total | kBtu | Read | |
| AV | 21 | Incremental volume total mode 1 | Single mode: Incremental volume total | gal | Read | |
| AV | 22 | Incremental volume total mode 2 | Single mode: Incremental volume total | gal | Read | |
| AV | 23 | Previous Year mode 1 volume total | Single mode: Previous year volume total | gal | Read | |
| AV | 24 | Previous Year mode 2 volume total | Single mode: Previous year volume total | gal | Read | |
| BV | 1 | Mode indication | Active mode | Read | 0=Mode 1, 1=Mode 2 | |
| BV | 2 | Location | Flow sensor location | Read | 0=Supply, 1=Return | |
| BV | 3 | User defined energy total reset, Mode 1 | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 4 | User defined energy total reset, Mode 2 | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 5 | User defined volume total reset, Mode 1 | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 6 | User defined volume total reset, Mode 2 | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 7 | Aux input 1 total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 8 | Aux input 2 total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 9 | Aux input 3 total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 10 | Flow direction | Reverse flow flag | Read | 1=Reverse flow | |
| MVmin | 1 | Meter Status | Operating status of the meter | Read | 1=Normal, 2=Low Supply Temperature, 3=High Supply Temperature, 4=Low Return Temperature, 5=High Return Temperature, 6=Delta T < Minimum, 7=High Energy Rate, 8=Low Signal Quality, 9=Comm error, 10=Low Supply Voltage, 11=System Fault | |
| TL | 1 | Log Data | Trend log multiple, 120 records | Read |
No points match these filters.
Object ID lookup: ONICON System-40 BTU Measurement System point IDs by name
AI1Energy rateAI2Volume rateAI3Supply temperatureAI4Return temperatureAI5Delta temperatureAI6Signal strengthAI7Signal qualityAI8Speed of soundAI9Peak energy rateAI10Average delta tempAV1Mode 1 energy totalAV2Mode 2 energy totalAV3Y-T-D mode 1 energy totalAV4Y-T-D mode 2 energy totalAV5Previous Year mode 1 energy totalAV6Previous Year mode 2 energy totalAV7User mode 1 energy totalAV8User mode 2 energy totalAV9Mode 1 volume totalAV10Mode 2 volume totalAV11Y-T-D mode 1 volume totalAV12Y-T-D mode 2 volume totalAV13User mode 1 volume totalAV14User mode 2 volume totalAV15Aux pulse input 1 totalAV16Aux pulse input 2 totalAV17Aux pulse input 3 totalAV18Run hoursAV19Incremental energy total mode 1AV20Incremental energy total mode 2AV21Incremental volume total mode 1AV22Incremental volume total mode 2AV23Previous Year mode 1 volume totalAV24Previous Year mode 2 volume totalBV1Mode indicationBV2LocationBV3User defined energy total reset, Mode 1BV4User defined energy total reset, Mode 2BV5User defined volume total reset, Mode 1BV6User defined volume total reset, Mode 2BV7Aux input 1 total resetBV8Aux input 2 total resetBV9Aux input 3 total resetBV10Flow directionMV1Meter StatusTL1Log Data
Integration notes
- The manual gives each object by identifier and function; Object_Name is shown only as "Various" (except MV 1 and TL 1). Names here are the dual mode function text; the description gives the single mode meaning.
- In single mode both objects of each mode 1/mode 2 pair are listed with the same single mode function (for example AV 1 and AV 2 "Energy total").
- Units shown are factory defaults and can be changed: energy kBtu, MBtu, ton-hours, kJ, MJ, kWh or MWh; volume gallons, liters, ft3 or m3; temperature °F or °C; speed of sound ft/s or m/s.
- There is no per-object read/write column. The reset BVs are marked W because writing 1 resets the total; the rest are shown as read-only.
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 System-40 BTU Measurement System 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 ONICON System-40 BTU Measurement System
How many BACnet points does the ONICON System-40 BTU Measurement System have?
This list has 46 BACnet objects: 10 analog inputs, 24 analog values, 10 binary values, 1 multi-state value, 1 trend log. The exact set on a given unit depends on its firmware, installed options and configuration.
Which ONICON System-40 BTU Measurement System BACnet points are writable?
7 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. The source has no read/write column, so this is inferred from object type.
Where is the official ONICON System-40 BTU Measurement System BACnet documentation?
The source is System-40 BTU Measurement System Installation and Operation Guide (DOC-0002831), revision Rev.H, published free by ONICON at https://www.onicon.com/wp-content/uploads/system-40-btu-measurement-system-manual-doc-0002831.pdf.
What are the minimum BACnet points to integrate the ONICON System-40 BTU Measurement System?
Start with AI 1 Energy rate (Energy rate, kBtu/h by default); AI 2 Volume rate (Flow rate, gpm by default); AI 3 Supply temperature (Supply water temperature); AI 4 Return temperature (Return water temperature); AV 1 Mode 1 energy total (Energy total (mode 1 total in dual mode)); AV 9 Mode 1 volume total (Volume total (mode 1 total in dual mode)); AI 7 Signal quality (Ultrasonic signal quality, 3 = best); MV 1 Meter Status (Meter status; 1 = Normal, 11 = System Fault).
How do I check these points on the real System-40 BTU Measurement System?
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 ONICON BACnet points lists
- Turbine flow meter (insertion)
ONICON F-1500 insertion turbine flow meter (BACnet MS/TP)
ONICON F-1500 series insertion turbine flow meters with the communication type set to BACnet MS/TP.
Also known as: F-1500, F-1500 Series Turbine Meter, ONICON F-1500 BACnet - Ultrasonic flow meter
ONICON F-4600 Inline Ultrasonic Flow Meter (LCD)
ONICON F-4600 inline ultrasonic flow meters with LCD and the BACnet MS/TP output.
Also known as: F-4600, F-4600-BAC, F4600, ONICON F-4600 - Electromagnetic flow meter
ONICON FT-3000 series (FT-3200) inline electromagnetic flow meter, BACnet MS/TP
ONICON FT-3000 series inline electromagnetic flow meters with the BACnet MS/TP output (PICS model FT-32**-*****-21**).
Also known as: FT-3200, FT-3000, FT-32**-*****-21**, ONICON FT-3000 BACnet - BTU (energy) meter
ONICON System-10-BAC BTU Meter Network Interface
ONICON System-10 BTU meters fitted with the BACnet network interface (BACnet MS/TP or BACnet IP).
Also known as: System-10-BAC, System-10, System 10 BTU meter, ONICON System-10 - BTU (energy) meter, two-channel
ONICON System-1000 Flow and Energy Measurement System
ONICON System-1000 flow and energy (BTU) meters, single or two-channel, with the BACnet MS/TP or BACnet IP network option.
Also known as: System-1000, SYS-1000, SYS-1100-111, SYS-1100-121, SYS-1200-111, SYS-1200-121, ONICON System 1000 BTU meter - BTU (energy) meter
ONICON System-20 BTU Meter
ONICON System-20 BTU meters with the RS485 BACnet MS/TP interface, used on chilled and hot water loops.
Also known as: System-20, System 20, ONICON System-20, S-20 BTU meter
Source: System-40 BTU Measurement System Installation and Operation Guide · DOC-0002831 · rev. Rev.H. Object names, instances and units are reproduced as published; descriptions are our own.