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Actuator / valve (6-way pressure-independent change-over valve) · Modbus register map
Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC) Modbus register map
Updated 28 October 2026
Belimo's 6-way EPIV serves two circuits (sequence 1 and sequence 2) through one valve and controls the flow in each with its own flow sensor. Over Modbus RTU one setpoint register covers both sequences (0-33 % and 67-100 %, with a closed dead band in between); the map also gives position, flow in three units, the active sequence, Vmax per sequence and fault flags.
This page lists 25 Modbus registers for the Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC) — 7 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
- 6-way EPIV Modbus RTU (EP..R-R6+BAC)
- Registers
- 25 (7 writable)
- Transport
- Modbus RTU
- Default unit ID
- 10
- Default serial
- 38400 baud, 8N2
- Documented addressing
- 1-based (subtract 1 for the wire address)
- 32-bit word order
- CDAB low word first (word-swapped)
- Also known as
- EP..R-R6+BAC, 6-way pressure-independent valve
Integration notes: Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC)
Set the address (factory 10) and frame with the Belimo Assistant app, write Setpoint source No. 119 = 1 (Bus), then write No. 1: 0-33 % runs sequence 1, 67-100 % sequence 2, 34-66 % closes. Poll No. 17 (active sequence), No. 7/10 (flow) and No. 105 (faults).
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 118 | Setpoint source | UINT16 | Setpoint source = Bus (default Analog) | Read/write |
| HR 0 | Setpoint | UINT16 | Setpoint across both sequences | Read/write |
| HR 16 | Active sequence | UINT16 | Active sequence | Read |
| HR 9 | Absolute volumetric flow (l/h) | UINT32 CDAB | Flow l/h | Read |
| HR 4 | Relative position | UINT16 | Relative position | Read |
| HR 104 | Malfunction and service information | BITMAP16 | Fault flags | Read |
Enable Modbus control & writes
Configure address and frame with the Belimo Assistant app, then write No. 119 = 1 so the valve follows the bus setpoint (factory setting is Analog).
Byte order & addressing
- Register No. is 1-based; subtract 1 for the wire address.
- Factory slave address is 10.
- One setpoint drives both sequences; 33 % and 67 % are both zero flow.
Network setup
- Default frame 1-8-N-2 at 38400 baud.
- No built-in terminator: fit an external 120 ohm resistor at the bus ends.
Watch out for
- While air bubbles are detected the valve stays in position control whatever Control mode says (bit 5 of No. 105).
Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC) 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 | Flow control: 0-33 % runs sequence 1, 67-100 % sequence 2. Position control: plain 0-100 %. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 1doc 2 | Override control | Forces a fixed position or flow. | UINT16 | Read/write | 0 = None; 1 = Open sequence 1 (0 %); 2 = Open sequence 2 (100 %); 3 = Close (50 %); 4 = Vmax sequence 1; 5 = Vmax sequence 2 | |||
| HR | 3doc 4 | Actuator type | UINT16 | Read | 0 = Actuator not connected; 1 = Air / water; 2 = VAV / EPIV; 3 = Fire; 4 = Energy Valve; 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 % of the active Vmax (Vmax1 or Vmax2). | UINT16 | × 0.01 | % | Read | ||
| HR | 7doc 8 | Absolute volumetric flow (selected unit) | Unit set by No. 118. | UINT32 | CDAB | × 0.001 | see No. 118 | Read | |
| HR | 9doc 10 | Absolute volumetric flow (l/h) | UINT32 | CDAB | × 0.001 | l/h | Read | ||
| HR | 11doc 12 | Absolute volumetric flow (gpm) | UINT32 | CDAB | × 0.001 | gpm | Read | ||
| HR | 13doc 14 | Flow setpoint (selected unit) | Active absolute flow setpoint; unit set by No. 118. | UINT32 | CDAB | × 0.001 | see No. 118 | Read | |
| HR | 15doc 16 | Setpoint analog | Analog control voltage when Setpoint source = Analog. | UINT16 | × 0.01 | V | Read | ||
| HR | 16doc 17 | Active sequence | UINT16 | Read | 0 = Sequence 1 (0-33 %); 1 = Sequence 2 (67-100 %); 2 = Dead band (34-66 %) | ||||
| 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 | Bus module firmware; 302 means version 3.02. | UINT16 | Read | ||||
| HR | 104doc 105 | Malfunction and service information | Bit-coded fault flags; several can be set at once. | BITMAP16 | Read | bit 2 = Error flow sensor; bit 3 = Actuator cannot move; bit 4 = Flow with closed valve; bit 5 = Air bubbles (runs in position control until cleared); bit 6 = Flow not reached within 3 min; bit 9 = Gear disengaged | |||
| HR | 105doc 106 | Vmax sequence 1 | Max flow for sequence 1, 5-100 %; default 100 %. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 106doc 107 | Vmax sequence 2 | Max flow for sequence 2, 5-100 %; default 100 %. | UINT16 | × 0.01 | % | Read/write | ||
| HR | 110doc 111 | Nominal volumetric flow (selected unit) | Vnom; unit set by No. 118. | UINT32 | CDAB | × 0.001 | see No. 118 | Read | |
| HR | 112doc 113 | Nominal volumetric flow (l/h) | UINT32 | CDAB | × 0.001 | l/h | Read | ||
| HR | 114doc 115 | Nominal volumetric flow (gpm) | UINT32 | CDAB | × 0.001 | gpm | Read | ||
| HR | 116doc 117 | Control mode | Default flow control. | UINT16 | Read/write | 0 = Position control; 1 = Flow control | |||
| HR | 117doc 118 | 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 | 118doc 119 | Setpoint source | Analog = 0-10 V on wire 3; Bus = No. 1. Default Analog. | UINT16 | Read/write | 0 = Analog; 1 = Bus |
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.
- Belimo states all values are unsigned 16-bit integers; unsupported registers read 65535. Writable registers from No. 101 up are persistent.
- The factory Modbus address of this valve is 10, not 1.
- The flow-setpoint pair (No. 14/15) is read-only in the description table even though the overview's access column is hard to read; it is listed as read-only.
- This edition has no bus watchdog or bus-fail registers, and the bus terminator must be fitted externally (120 ohm).
- Registers 3, 108-110 are unused and not listed.
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 6-way EPIV Modbus RTU (EP..R-R6+BAC)
What Modbus registers does the Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC) have?
This map lists 25 registers: 25 holding registers. 7 of them can be written. Registers vary with firmware, options and configuration, so confirm against the device.
Are the Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC) 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 6-way EPIV Modbus RTU (EP..R-R6+BAC) 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 6-way EPIV Modbus RTU (EP..R-R6+BAC)?
Start with HR 118 Setpoint source (Setpoint source = Bus (default Analog)); HR 0 Setpoint (Setpoint across both sequences); HR 16 Active sequence (Active sequence); HR 9 Absolute volumetric flow (l/h) (Flow l/h); HR 4 Relative position (Relative position); HR 104 Malfunction and service information (Fault flags).
How do I enable Modbus control of the Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC)?
Configure address and frame with the Belimo Assistant app, then write No. 119 = 1 so the valve follows the bus setpoint (factory setting is Analog).
Where is the official Belimo 6-way EPIV Modbus RTU (EP..R-R6+BAC) Modbus documentation?
The source is Modbus Register - 6-way EPIV (6-way EPIV Modbus Register en-gb 2024-01), revision 2024-01, published free by Belimo at https://www.belimo.com/mam/general-documents/system_integration/Modbus/belimo_Modbus-Register_6way-EPIV_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 (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 - Actuator / valve (pressure-independent control valve with energy metering)
Belimo Energy Valve DN 15-50 (Version 4) Modbus RTU / TCP
Belimo Energy Valve Version 4, DN 15-50 (EV..R2+(K)BAC, EV..R2+MID, EV..R3+BAC), per Energy Valve Modbus interface description en-gb 2023-08.
Also known as: EV..R2+BAC, EV..R2+KBAC, EV..R2+MID, EV..R3+BAC, Energy Valve 4
Source: Modbus Register - 6-way EPIV · 6-way EPIV Modbus Register en-gb 2024-01 · rev. 2024-01. Register numbers, types, scaling and units are reproduced as published; descriptions are our own.