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Actuator / valve (pressure-independent control valve with energy metering) · Modbus register map
Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP Modbus register map
Updated 28 October 2026
Belimo's Energy Valve combines a pressure-independent control valve, a flow sensor and two temperature sensors, so it reports flow, delta T, heating/cooling power and energy totals. Version 4 offers Modbus RTU on RS-485 and Modbus TCP on its Ethernet port. Most values are given three times - in SI, imperial and a user-selected unit - and large values use two registers, low word first.
This page lists 80 Modbus registers for the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP — 30 writable — with the table, 0-based wire address, data type, word order, scale, units and access of each, re-typed from Belimo’s own free documentation (linked below) and checked against it.
- Manufacturer
- Belimo
- Model
- Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP
- Registers
- 80 (30 writable)
- Transport
- Modbus RTU, Modbus TCP
- Default unit ID
- 1
- Default serial
- 38400 baud, 8N2
- TCP port
- 502
- Documented addressing
- 1-based (subtract 1 for the wire address)
- 32-bit word order
- CDAB low word first (word-swapped)
- Firmware
- Version 4 devices (firmware example in the document: 400 = 4.00)
- Also known as
- EV..R2+BAC, EV..R2+KBAC, EV..R2+MID, EV..R3+BAC, Energy Valve 4
Integration notes: Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP
Pick RTU (RS-485, 38400 8N2, address 1) or TCP (port 502), keep Setpoint source = Bus, choose Control mode (No. 117), then write the setpoint to No. 1 (address 0) and poll flow, temperatures, power and energy. Read each 32-bit value as a two-register pair, low word first.
Minimum registers to map
Addresses are 0-based wire addresses. Enough to monitor and run the unit; map more as the job needs.
| Register | Name | Type | Why | Access |
|---|---|---|---|---|
| HR 0 | Setpoint | UINT16 | Setpoint, 0.01 % | Read/write |
| HR 116 | Control mode | UINT16 | Control mode: position / flow / power | Read/write |
| HR 7 | Absolute volumetric flow (l/s) | UINT16 | Flow l/s | Read |
| HR 19 | Temperature 1 external (°C) | INT16 | Temperature 1 (external) °C | Read |
| HR 21 | Temperature 2 integrated (°C) | INT16 | Temperature 2 (integrated) °C | Read |
| HR 27 | Cooling power (kW) | UINT32 CDAB | Cooling power kW | Read |
| HR 33 | Heating power (kW) | UINT32 CDAB | Heating power kW | Read |
| HR 65 | Cooling energy (kWh) | UINT32 CDAB | Cooling energy kWh | Read |
| HR 71 | Heating energy (kWh) | UINT32 CDAB | Heating energy kWh | Read |
| HR 104 | Malfunction and service information | BITMAP16 | Fault flags | Read |
Enable Modbus control & writes
Modbus RTU and TCP are configured with the Belimo Assistant app or the valve's built-in web server (address, baud, frame, IP). Setpoint source (No. 119) defaults to Bus.
Communication loss & watchdog
Bus fail setpoint is No. 109 and the timeout No. 110 (0-3600 s, 0 = off, default 120 s once a fail setpoint is set): if neither No. 1 nor No. 2 is renewed in time the valve goes to the fail setpoint. Belimo marks No. 110 as not functional in this edition, so test it before relying on it.
Byte order & addressing
- Register No. is 1-based; subtract 1 for the wire address.
- 32-bit pairs are low word first (CDAB) and must be written with a single FC 16 to just those two registers.
- Each quantity appears in SI, imperial and 'selected unit' registers; the selected-unit registers follow No. 148-151.
Network setup
- RTU default frame 1-8-N-2 at 38400 baud, address 1; 9600-115200 baud supported.
- TCP default port 502 over the Ethernet socket.
- Max. 32 RTU nodes per segment without a repeater; terminate with 120 ohm.
Watch out for
- Unsupported values read 65535 - treat it as 'not available', not as a real reading.
- Temperatures are signed; read them as INT16.
Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP Modbus registers
Address = 0-based wire address (the documented number is shown under it when it differs) · Order: ABCD = high word first, CDAB = low word first · Scale: engineering value = raw × scale.
| Table | Address | Name | Description | Type | Order | Scale | Units | Access | Values / bits |
|---|---|---|---|---|---|---|---|---|---|
| HR | 0doc 1 | Setpoint | Relative setpoint 0-100 %. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 1doc 2 | Override control | Forces a fixed valve state instead of the setpoint. | UINT16 | Read/write | 0 = None; 1 = Open valve; 2 = Close valve; 3 = Minimum flow; 5 = Maximum flow; 6 = Nominal flow; 10 = Motor stop | |||
| HR | 2doc 3 | Command | Service command (Sync). | UINT16 | Read/write | 0 = None; 2 = Sync | |||
| HR | 3doc 4 | Actuator type | UINT16 | Read | 0 = Device not connected; 1 = Air/water; 2 = VAV / EPIV; 3 = Fire; 4 = Energy Valve / flow meter; 5 = 6-way EPIV | ||||
| HR | 4doc 5 | Relative position | UINT16 | × 0.01 | % | Read | |||
| HR | 5doc 6 | Absolute position | UINT16 | × 0.01 | ° | Read | |||
| HR | 6doc 7 | Relative volumetric flow | Flow as a percentage of Vnom. | UINT16 | × 0.01 | % | Read | ||
| HR | 7doc 8 | Absolute volumetric flow (l/s) | UINT16 | × 0.01 | l/s | Read | |||
| HR | 8doc 9 | Absolute volumetric flow (gpm) | UINT16 | × 0.1 | gpm | Read | |||
| HR | 9doc 10 | Absolute volumetric flow (selected unit) | Unit set by No. 148. | UINT32 | CDAB | × 0.001 | see No. 148 | Read | |
| HR | 11doc 12 | Setpoint analog | Setpoint seen on the analog input when Setpoint source = Analog. | UINT16 | × 0.01 | % | Read | ||
| HR | 13doc 14 | Sensor 1 temperature (°C) | Sensor 1 input as temperature (passive sensor types). | INT16 | × 0.01 | °C | Read | ||
| HR | 14doc 15 | Sensor 1 temperature (°F) | INT16 | × 0.01 | °F | Read | |||
| HR | 15doc 16 | Flow setpoint (l/s) | Active absolute flow setpoint. | UINT16 | × 0.01 | l/s | Read | ||
| HR | 16doc 17 | Flow setpoint (gpm) | UINT16 | × 0.1 | gpm | Read | |||
| HR | 17doc 18 | Flow setpoint (selected unit) | Unit set by No. 148. | UINT32 | CDAB | × 0.001 | see No. 148 | Read | |
| HR | 19doc 20 | Temperature 1 external (°C) | Remote (external) temperature sensor. | INT16 | × 0.01 | °C | Read | ||
| HR | 20doc 21 | Temperature 1 external (°F) | INT16 | × 0.01 | °F | Read | |||
| HR | 21doc 22 | Temperature 2 integrated (°C) | Integrated temperature sensor. | INT16 | × 0.01 | °C | Read | ||
| HR | 22doc 23 | Temperature 2 integrated (°F) | INT16 | × 0.01 | °F | Read | |||
| HR | 23doc 24 | Delta T (K) | Temperature difference between the two sensors. | UINT16 | × 0.01 | K | Read | ||
| HR | 24doc 25 | Delta T (°F) | UINT16 | × 0.01 | °F | Read | |||
| HR | 25doc 26 | Glycol concentration | UINT16 | × 0.01 | % | Read | |||
| HR | 26doc 27 | Relative power | UINT16 | × 0.01 | % | Read | |||
| HR | 27doc 28 | Cooling power (kW) | UINT32 | CDAB | × 0.001 | kW | Read | ||
| HR | 29doc 30 | Cooling power (kBTU/h) | UINT32 | CDAB | × 0.001 | kBTU/h | Read | ||
| HR | 31doc 32 | Cooling power (selected unit) | Unit set by No. 149. | UINT32 | CDAB | × 0.1 | see No. 149 | Read | |
| HR | 33doc 34 | Heating power (kW) | UINT32 | CDAB | × 0.001 | kW | Read | ||
| HR | 35doc 36 | Heating power (kBTU/h) | UINT32 | CDAB | × 0.001 | kBTU/h | Read | ||
| HR | 37doc 38 | Heating power (selected unit) | Unit set by No. 149. | UINT32 | CDAB | × 0.1 | see No. 149 | Read | |
| HR | 39doc 40 | Delta T setpoint (K) | Delta T setpoint, 1.00-55.00 K. | UINT16 | × 0.01 | K | Read/write | ||
| HR | 40doc 41 | Delta T setpoint (°F) | Same setpoint in °F, 1.80-99.00. | UINT16 | × 0.01 | °F | Read/write | ||
| HR | 41doc 42 | Flow limit for Delta T (l/s) | Absolute flow setpoint used by the Delta T function. | UINT32 | CDAB | × 0.001 | l/s | Read/write | |
| HR | 43doc 44 | Flow limit for Delta T (gpm) | UINT32 | CDAB | × 0.01 | gpm | Read/write | ||
| HR | 45doc 46 | Flow limit for Delta T (selected unit) | Unit set by No. 148. | UINT32 | CDAB | × 0.001 | see No. 148 | Read/write | |
| HR | 59doc 60 | Total volume (m3) | UINT32 | CDAB | × 0.01 | m3 | Read | ||
| HR | 61doc 62 | Total volume (gal) | UINT32 | CDAB | gal | Read | |||
| HR | 63doc 64 | Total volume (selected unit) | Unit set by No. 150. | UINT32 | CDAB | see No. 150 | Read | ||
| HR | 65doc 66 | Cooling energy (kWh) | UINT32 | CDAB | kWh | Read | |||
| HR | 67doc 68 | Cooling energy (kBTU) | UINT32 | CDAB | kBTU | Read | |||
| HR | 69doc 70 | Cooling energy (selected unit) | Unit set by No. 151. | UINT32 | CDAB | see No. 151 | Read | ||
| HR | 71doc 72 | Heating energy (kWh) | UINT32 | CDAB | kWh | Read | |||
| HR | 73doc 74 | Heating energy (kBTU) | UINT32 | CDAB | kBTU | Read | |||
| HR | 75doc 76 | Heating energy (selected unit) | Unit set by No. 151. | UINT32 | CDAB | see No. 151 | Read | ||
| HR | 99doc 100 | Bus termination | Shows whether the 120 ohm terminator is enabled (set with the tools). | UINT16 | Read | 0 = Disabled; 1 = Enabled | |||
| HR | 100doc 101 | Series number 1st part | First block of the serial number on the housing label. | UINT16 | Read | ||||
| HR | 101doc 102 | Series number 2nd part | Second block of the serial number. | UINT16 | Read | ||||
| HR | 102doc 103 | Series number 4th part | Fourth block of the serial number (the third is not exposed). | UINT16 | Read | ||||
| HR | 103doc 104 | Firmware version | Communication module firmware; 400 means version 4.00. | UINT16 | Read | ||||
| HR | 104doc 105 | Malfunction and service information | Bit-coded fault flags; several can be set at once. | BITMAP16 | Read | bit 0 = No communication to actuator; bit 1 = Gear disengaged; bit 2 = Actuator cannot move; bit 3 = Reverse flow; bit 4 = Flow setpoint not reached (15 min); bit 5 = Flow with closed valve; bit 6 = Actual flow exceeds nominal flow; bit 7 = Flow measurement error (air in system); bit 8 = External temperature sensor error; bit 9 = Integrated temperature sensor error; bit 10 = Communication to flow sensor interrupted; bit 11 = Freeze warning; bit 12 = Glycol detected; bit 13 = Power setpoint not reached (15 min) | |||
| HR | 105doc 106 | Vmin | Minimum flow limit in %, 0 up to Vmax; default 0. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 106doc 107 | Vmax | Maximum flow limit, 25-100 %; cannot go below Vmin. Default 100 %. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 108doc 109 | Bus fail setpoint | Setpoint used when the bus watchdog expires. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 109doc 110 | Communication watchdog | Bus timeout; Belimo marks it not functional / reserved in this edition. | UINT16 | s | Read/write | |||
| HR | 110doc 111 | Nominal volumetric flow (l/s) | Vnom of the valve. | UINT16 | × 0.01 | l/s | Read | ||
| HR | 111doc 112 | Nominal volumetric flow (gpm) | UINT16 | × 0.1 | gpm | Read | |||
| HR | 112doc 113 | Nominal volumetric flow (selected unit) | Unit set by No. 148. | UINT32 | CDAB | × 0.001 | see No. 148 | Read | |
| HR | 116doc 117 | Control mode | How the setpoint is interpreted. Default flow control. | UINT16 | Read/write | 0 = Position control; 1 = Flow control; 2 = Power control | |||
| HR | 118doc 119 | Setpoint source | Bus = No. 1; Analog = 0.5-10 V on wire 3. Default Bus. | UINT16 | Read/write | 0 = Analog; 1 = Bus | |||
| HR | 120doc 121 | Sensor 1 type | Extra sensor input; selectable only when Setpoint source = Bus. | UINT16 | Read/write | 0 = None; 1 = Active; 3 = Passive; 4 = Switch | |||
| HR | 121doc 122 | Sensor 1 passive sensor type | UINT16 | Read/write | 0 = Resistance measurement; 1 = PT1000; 2 = Ni1000; 7 = NTC10k2; 8 = NTC10k3 | ||||
| HR | 129doc 130 | Vmin (l/s) | UINT16 | × 0.01 | l/s | Read/write | |||
| HR | 130doc 131 | Vmin (gpm) | UINT16 | × 0.1 | gpm | Read/write | |||
| HR | 131doc 132 | Vmin (selected unit) | Unit set by No. 148. | UINT32 | CDAB | × 0.001 | see No. 148 | Read/write | |
| HR | 133doc 134 | Vmax (l/s) | UINT16 | × 0.01 | l/s | Read/write | |||
| HR | 134doc 135 | Vmax (gpm) | UINT16 | × 0.1 | gpm | Read/write | |||
| HR | 147doc 148 | Unit selection flow | Default l/h. | UINT16 | Read/write | 0 = m3/s; 1 = m3/h; 2 = l/s; 3 = l/min; 4 = l/h; 5 = gpm; 6 = cfm | |||
| HR | 148doc 149 | Unit selection power | Default kW. | UINT16 | Read/write | 0 = W; 1 = kW; 2 = MW; 3 = BTU/h; 4 = kBTU/h; 5 = ton | |||
| HR | 149doc 150 | Unit selection volume | Default m3. | UINT16 | Read/write | 0 = m3; 1 = Litre; 2 = Gallon; 3 = cf | |||
| HR | 150doc 151 | Unit selection energy | Default kWh. | UINT16 | Read | 0 = J; 1 = kJ; 2 = MJ; 3 = GJ; 4 = Wh; 5 = kWh; 6 = MWh; 7 = BTU; 8 = kBTU; 9 = ton | |||
| HR | 159doc 160 | Nominal power (kW) | UINT32 | CDAB | × 0.001 | kW | Read | ||
| HR | 161doc 162 | Nominal power (kBTU/h) | UINT32 | CDAB | × 0.001 | kBTU/h | Read | ||
| HR | 163doc 164 | Nominal power (selected unit) | Unit set by No. 149. | UINT32 | CDAB | × 0.1 | see No. 149 | Read | |
| HR | 165doc 166 | Max power | Power limit as % of nominal power, 0.5-100 %. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 166doc 167 | Absolute Pmax (kW) | Power limit, 0.5 % of Pnom up to Pnom. | UINT32 | CDAB | × 0.001 | kW | Read/write | |
| HR | 168doc 169 | Absolute Pmax (kBTU/h) | UINT32 | CDAB | × 0.001 | kBTU/h | Read/write | ||
| HR | 170doc 171 | Absolute Pmax (selected unit) | Unit set by No. 149. | UINT32 | CDAB | × 0.1 | see No. 149 | Read/write | |
| HR | 179doc 180 | Delta T limitation | Turns the Delta T Manager on. Default disabled. | UINT16 | Read/write | 0 = Disabled; 1 = dT-Manager; 2 = dT-Manager scaling | |||
| HR | 180doc 181 | Delta T Manager status | UINT16 | Read | 0 = Not selected; 1 = Standby; 2 = Active; 3 = Scaling standby; 4 = Scaling active | ||||
| HR | 204doc 205 | Select meter register | Certified (MID models only) or lifetime totals for No. 60-77; avoid toggling. | UINT16 | Read/write | 0 = Certified meter register; 1 = Lifetime meter register |
Notes on this map
- 32-bit values occupy two registers with the low word first (Belimo's worked example: No. 10 = 14551, No. 11 = 19 gives 19 x 65536 + 14551 = 1,259,735), so they are UINT32 with CDAB word order. Write a 32-bit pair with one FC 16 request covering only those two registers.
- Values are unsigned unless Belimo marks them signed (**): the sensor-1 and Temperature 1/2 registers (No. 14, 15, 20-23) are signed two's complement and typed INT16 here.
- Unsupported registers read 65535. Writable registers from No. 101 up are persistent; don't write them cyclically.
- The description table prints Sensor 1 °C/°F (No. 123/124) with addresses 124/125, which does not match the No.-minus-1 rule used everywhere else, so those two are left out. No. 13 (raw sensor value, scale depends on sensor type) is also left out.
- No. 136/137 (Vmax in selected unit) is left out: its scaling is printed as '0.001-' and is unclear. No. 201-204 (sensor serial number / production order and sequence numbers) are left out because the document does not say whether each pair is one 32-bit value.
- No. 9 (flow gpm) has no access letter in the description table; it is read-only like its neighbours. No. 151 has no access letter either and is listed as read-only to be safe, although the other unit selections are R/W.
- Belimo lists Communication watchdog (No. 110) as 'not functional, reserved for future' in this edition, so don't rely on it.
Check it against the live device. A register map tells you what the controller can expose; the unit in front of you may differ by firmware or options. Read a few registers and compare them with the unit’s own display; for a 32-bit value the float and byte-order decoder shows all four word orders at once, so a wrong word order or scale is obvious. New to this? Read what a register map is and why addresses are off by one.
Questions about the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP
What Modbus registers does the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP have?
This map lists 80 registers: 80 holding registers. 30 of them can be written. Registers vary with firmware, options and configuration, so confirm against the device.
Are the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP Modbus addresses 0-based or 1-based?
The manufacturer's document numbers registers 1-based (subtract 1 for the wire address). Every address on this page is the 0-based wire address you put in the request; the documented number is shown under it where it differs. Belimo prints each register twice: 'No.' counts from 1 and 'Address' from 0, and the documented value here is the No. column. Register No. 1 (setpoint) is wire address 0. Every value sits in one flat table, so holding-register reads (FC 3) and writes (FC 6/16) reach everything; FC 4 input-register reads of the same addresses also work.
What byte order does the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP use for 32-bit values?
Multi-register values in this map use CDAB (low word first (word-swapped)). Set your client to this order for every 32/64-bit value in the table.
What are the minimum Modbus registers to integrate the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP?
Start with HR 0 Setpoint (Setpoint, 0.01 %); HR 116 Control mode (Control mode: position / flow / power); HR 7 Absolute volumetric flow (l/s) (Flow l/s); HR 19 Temperature 1 external (°C) (Temperature 1 (external) °C); HR 21 Temperature 2 integrated (°C) (Temperature 2 (integrated) °C); HR 27 Cooling power (kW) (Cooling power kW); HR 33 Heating power (kW) (Heating power kW); HR 65 Cooling energy (kWh) (Cooling energy kWh); HR 71 Heating energy (kWh) (Heating energy kWh); HR 104 Malfunction and service information (Fault flags).
How do I enable Modbus control of the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP?
Modbus RTU and TCP are configured with the Belimo Assistant app or the valve's built-in web server (address, baud, frame, IP). Setpoint source (No. 119) defaults to Bus.
What happens when the Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP loses Modbus communication?
Bus fail setpoint is No. 109 and the timeout No. 110 (0-3600 s, 0 = off, default 120 s once a fail setpoint is set): if neither No. 1 nor No. 2 is renewed in time the valve goes to the fail setpoint. Belimo marks No. 110 as not functional in this edition, so test it before relying on it.
Where is the official Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP Modbus documentation?
The source is Energy Valve Modbus Interface Description - Energy Valve DN 15...50 (Version 4) (en-gb 2023-08 (general notes dated 15.01.2022)), revision 2023-08, published free by Belimo at https://www.belimo.com/mam/general-documents/system_integration/Modbus/belimo_Modbus-Register_Energy-Valve_V4_1_en-gb.pdf.
More Belimo Modbus register maps
- Actuator / valve (pressure-independent characterised control valve)
Belimo 2-way EPIV DN 15-50 (Version 4.2) Modbus RTU
Belimo 2-way EPIV DN 15-50 Version 4 (EP..R2+(K)BAC) on Modbus RTU, per interface description edition 2025-09 / V4.2.
Also known as: EP..R2+BAC, EP..R2+KBAC, Electronic pressure-independent valve - Actuator / valve (6-way pressure-independent change-over valve)
Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC)
Belimo 6-way EPIV EP..R-R6+BAC on Modbus RTU, per 6-way EPIV Modbus Register en-gb 2024-01 (general notes dated 16.12.2019).
Also known as: EP..R-R6+BAC, 6-way pressure-independent valve - Actuator / valve (damper and valve actuator)
Belimo Air/water actuators with Modbus RTU (..24A-MOD)
Belimo ..M(C)24A-MOD, ..R24A-MOD, ..V(K)24A-MOD, ..F24A-MOD, ..RF24A-MOD and ..H24A-MOD air/water actuators, per Modbus interface description edition 2026-05 / V3.08.
Also known as: LM24A-MOD, NM24A-MOD, SM24A-MOD, GM24A-MOD, LMC24A-MOD, NMC24A-MOD, NR24A-MOD, LR24A-MOD, NV24A-MOD, NVK24A-MOD, LF24A-MOD, NF24A-MOD, NRF24A-MOD, LRF24A-MOD, LH24A-MOD, SH24A-MOD
Source: Energy Valve Modbus Interface Description - Energy Valve DN 15...50 (Version 4) · en-gb 2023-08 (general notes dated 15.01.2022) · rev. 2023-08. Register numbers, types, scaling and units are reproduced as published; descriptions are our own.