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BTU (energy) meter · BACnet points list
ONICON System-20 BTU Meter BACnet points list
Updated 4 November 2026
The System-20 calculates thermal energy from a flow meter and a matched pair of supply and return temperature sensors. Over BACnet MS/TP it reports energy and flow rates, both temperatures, energy and volume totals, auxiliary pulse totals and a meter status code. In dual mode it keeps separate totals for two modes (for example heating and cooling), so the totals come in single mode, mode 1 and mode 2 sets.
This page lists 55 BACnet objects for the ONICON System-20 BTU Meter — 9 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-20 BTU Meter
- Equipment
- BTU (energy) meter
- Equipment type
- Thermostats, sensors & meters
- BACnet objects
- 55 (9 writable)
- Transport
- BACnet MS/TP
- Firmware
- Software version 0.1.15 and higher
- Default device instance
- 57017
- Also known as
- System-20, System 20, ONICON System-20, S-20 BTU meter
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-20 BTU Meter
Read the energy rate, flow rate and the two temperatures for live trending, plus the energy and volume totals for the mode the meter runs in. Watch MV 1 Meter Status for sensor and supply faults. Nothing needs to be written except the optional total resets.
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 | Single mode energy total | Energy total when run in single mode | Read |
| AV 16 | Single mode volume total | Volume total when run in single mode | Read |
| MV 1 | Meter Status | Meter status; 1 = Normal, 11 = System Fault | Read |
Network setup
- BACnet MS/TP on terminal block TB1, 2-wire half duplex, 1/4 unit load.
- MAC address 1-255 per the specification (the display menu shows 0-127), default 17. Device instance default 57017, writable.
- Baud 9600, 19200, 38400 or 76800; default 38400. 120 ohm termination selectable, default off; no biasing.
- Protocol (BACnet or Modbus), address, instance and baud are set from the meter display menu.
Watch out for
- Pick the totals that match the operating mode: the single mode objects cover single mode, the mode 1 and mode 2 objects cover dual mode.
- Reset the user-defined and aux totals only through the reset BVs (write 1).
- The trend log multiple holds 120 records and rolls over; the interval can be set from 30 s to 1 h, default 15 min.
ONICON System-20 BTU Meter 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 | Peak energy rate | Interval set by the trend log object | kBtu/h | Read | |
| AI | 7 | Average delta temp | Interval set by the trend log object | °F | Read | |
| AVmin | 1 | Single mode energy total | kBtu | Read | ||
| AV | 2 | Mode 1 energy total | kBtu | Read | ||
| AV | 3 | Mode 2 energy total | kBtu | Read | ||
| AV | 4 | Single mode Y-T-D energy total | kBtu | Read | ||
| AV | 5 | Mode 1 Y-T-D energy total | kBtu | Read | ||
| AV | 6 | Mode 2 Y-T-D energy total | kBtu | Read | ||
| AV | 7 | Single mode previous year energy total | kBtu | Read | ||
| AV | 8 | Mode 1 previous year energy total | kBtu | Read | ||
| AV | 9 | Mode 2 previous year energy total | kBtu | Read | ||
| AV | 10 | Single mode user defined energy total | kBtu | Read | ||
| AV | 11 | Mode 1 user defined energy total | kBtu | Read | ||
| AV | 12 | Mode 2 user defined energy total | kBtu | Read | ||
| AV | 13 | Single mode incremental energy total | Incremental total, logged by the trend log | kBtu | Read | |
| AV | 14 | Mode 1 incremental energy total | Incremental total, logged by the trend log | kBtu | Read | |
| AV | 15 | Mode 2 incremental energy total | Incremental total, logged by the trend log | kBtu | Read | |
| AVmin | 16 | Single mode volume total | gal | Read | ||
| AV | 17 | Mode 1 volume total | gal | Read | ||
| AV | 18 | Mode 2 volume total | gal | Read | ||
| AV | 19 | Single mode Y-T-D volume total | Marked * (trend log interval) in the manual | gal | Read | |
| AV | 20 | Mode 1 Y-T-D volume total | Marked * (trend log interval) in the manual | gal | Read | |
| AV | 21 | Mode 2 Y-T-D volume total | Marked * (trend log interval) in the manual | gal | Read | |
| AV | 22 | Single mode previous year volume total | Marked * (trend log interval) in the manual | gal | Read | |
| AV | 23 | Mode 1 previous year volume total | gal | Read | ||
| AV | 24 | Mode 2 previous year volume total | gal | Read | ||
| AV | 25 | Single mode user defined volume total | gal | Read | ||
| AV | 26 | Mode 1 user defined volume total | gal | Read | ||
| AV | 27 | Mode 2 user defined volume total | gal | Read | ||
| AV | 28 | Single mode incremental volume total | Incremental total, logged by the trend log | gal | Read | |
| AV | 29 | Mode 1 incremental volume total | Incremental total, logged by the trend log | gal | Read | |
| AV | 30 | Mode 2 incremental volume total | Incremental total, logged by the trend log | gal | Read | |
| AV | 31 | Aux pulse input 1 total | Pulse count | Read | ||
| AV | 32 | Aux pulse input 2 total | Pulse count | Read | ||
| AV | 33 | Aux pulse input 3 total | Pulse count | Read | ||
| AV | 34 | Run hours | h | Read | ||
| BV | 1 | Mode indication | Active mode | Read | 0=Mode 1, 1=Mode 2 | |
| BV | 2 | Location | Flow meter location | Read | 0=Supply, 1=Return | |
| BV | 3 | Single mode user energy total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 4 | Mode 1 user energy total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 5 | Mode 2 user energy total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 6 | Single mode user volume total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 7 | Mode 1 user volume total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 8 | Mode 2 user volume total reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 9 | Aux total 1 reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 10 | Aux total 2 reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 11 | Aux total 3 reset | Write 1 to reset this total | Write | 1 = reset total | |
| BV | 12 | 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, 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-20 BTU Meter point IDs by name
AI1Energy rateAI2Volume rateAI3Supply temperatureAI4Return temperatureAI5Delta temperatureAI6Peak energy rateAI7Average delta tempAV1Single mode energy totalAV2Mode 1 energy totalAV3Mode 2 energy totalAV4Single mode Y-T-D energy totalAV5Mode 1 Y-T-D energy totalAV6Mode 2 Y-T-D energy totalAV7Single mode previous year energy totalAV8Mode 1 previous year energy totalAV9Mode 2 previous year energy totalAV10Single mode user defined energy totalAV11Mode 1 user defined energy totalAV12Mode 2 user defined energy totalAV13Single mode incremental energy totalAV14Mode 1 incremental energy totalAV15Mode 2 incremental energy totalAV16Single mode volume totalAV17Mode 1 volume totalAV18Mode 2 volume totalAV19Single mode Y-T-D volume totalAV20Mode 1 Y-T-D volume totalAV21Mode 2 Y-T-D volume totalAV22Single mode previous year volume totalAV23Mode 1 previous year volume totalAV24Mode 2 previous year volume totalAV25Single mode user defined volume totalAV26Mode 1 user defined volume totalAV27Mode 2 user defined volume totalAV28Single mode incremental volume totalAV29Mode 1 incremental volume totalAV30Mode 2 incremental volume totalAV31Aux pulse input 1 totalAV32Aux pulse input 2 totalAV33Aux pulse input 3 totalAV34Run hoursBV1Mode indicationBV2LocationBV3Single mode user energy total resetBV4Mode 1 user energy total resetBV5Mode 2 user energy total resetBV6Single mode user volume total resetBV7Mode 1 user volume total resetBV8Mode 2 user volume total resetBV9Aux total 1 resetBV10Aux total 2 resetBV11Aux total 3 resetBV12Flow directionMV1Meter StatusTL1Log Data
Integration notes
- The manual lists each object by identifier and function; the Object_Name property is shown only as "Various". Names here are the printed function text.
- Single mode objects accumulate when the meter runs in single mode; Mode 1 and Mode 2 objects accumulate in dual mode. BV 1 shows the active mode.
- Units shown are the factory defaults. Energy can be kBtu, MBtu, ton-hours, kJ, MJ, kWh or MWh; volume gallons, liters, ft3 or m3; temperature °F or °C.
- The protocol statement counts 10 analog inputs, but only AI 1 to AI 7 are described in the object table.
- There is no read/write column per object. The reset BVs are marked W because writing 1 resets the total; the rest are shown as read-only.
- The numbered MV 1 states skip 8; the State_Text list in the same section has Low Signal Quality in that position.
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-20 BTU Meter 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-20 BTU Meter
How many BACnet points does the ONICON System-20 BTU Meter have?
This list has 55 BACnet objects: 7 analog inputs, 34 analog values, 12 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-20 BTU Meter BACnet points are writable?
9 of the 55 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-20 BTU Meter BACnet documentation?
The source is System-20 BTU Meter Installation and Operation Guide (DOC-0003557), revision Rev.F, published free by ONICON at https://www.onicon.com/wp-content/uploads/system-20-btu-meter-manual-doc-0003557.pdf.
What are the minimum BACnet points to integrate the ONICON System-20 BTU Meter?
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 Single mode energy total (Energy total when run in single mode); AV 16 Single mode volume total (Volume total when run in single mode); MV 1 Meter Status (Meter status; 1 = Normal, 11 = System Fault).
How do I check these points on the real System-20 BTU Meter?
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
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ONICON FT-3000 series inline electromagnetic flow meters with the BACnet MS/TP output (PICS model FT-32**-*****-21**).
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ONICON System-10-BAC BTU Meter Network Interface
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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.
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ONICON System-40 BTU Measurement System
ONICON System-40 BTU measurement systems (clamp-on ultrasonic flow plus supply/return temperature) with the BACnet MS/TP interface.
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Source: System-20 BTU Meter Installation and Operation Guide · DOC-0003557 · rev. Rev.F. Object names, instances and units are reproduced as published; descriptions are our own.