{
 "manufacturer": "Belimo",
 "manufacturer_slug": "belimo",
 "model": "6-way EPIV Modbus RTU (EP..R-R6+BAC)",
 "model_slug": "epiv-6-way",
 "short_model": "Belimo 6-way EPIV",
 "aliases": [
  "EP..R-R6+BAC",
  "6-way pressure-independent valve"
 ],
 "equipment_type": "Actuator / valve (6-way pressure-independent change-over valve)",
 "applies_to": "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).",
 "summary": "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.",
 "transport": [
  "RTU"
 ],
 "defaults": {
  "unit_id": 10,
  "baud": 38400,
  "parity": "None",
  "data_bits": 8,
  "stop_bits": 2,
  "tcp_port": null
 },
 "addressing": {
  "convention": "1-based",
  "note": "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."
 },
 "default_word_order": "CDAB",
 "firmware": null,
 "source": {
  "title": "Modbus Register - 6-way EPIV",
  "doc_number": "6-way EPIV Modbus Register en-gb 2024-01",
  "revision_date": "2024-01",
  "url": "https://www.belimo.com/mam/general-documents/system_integration/Modbus/belimo_Modbus-Register_6way-EPIV_en-gb.pdf",
  "pages": "General notes p. 2; register overview p. 3; register description pp. 4-6"
 },
 "notes": [
  "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."
 ],
 "registers": [
  {
   "table": "holding_register",
   "address": 0,
   "documented": "1",
   "name": "Setpoint",
   "description": "Flow control: 0-33 % runs sequence 1, 67-100 % sequence 2. Position control: plain 0-100 %.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 0.01,
   "units": "%",
   "access": "RW",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 1,
   "documented": "2",
   "name": "Override control",
   "description": "Forces a fixed position or flow.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "RW",
   "values": {
    "0": "None",
    "1": "Open sequence 1 (0 %)",
    "2": "Open sequence 2 (100 %)",
    "3": "Close (50 %)",
    "4": "Vmax sequence 1",
    "5": "Vmax sequence 2"
   },
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 3,
   "documented": "4",
   "name": "Actuator type",
   "description": "",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "R",
   "values": {
    "0": "Actuator not connected",
    "1": "Air / water",
    "2": "VAV / EPIV",
    "3": "Fire",
    "4": "Energy Valve",
    "5": "6-way EPIV"
   },
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 4,
   "documented": "5",
   "name": "Relative position",
   "description": "",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 0.01,
   "units": "%",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 5,
   "documented": "6",
   "name": "Absolute position",
   "description": "",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 0.01,
   "units": "°",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 6,
   "documented": "7",
   "name": "Relative volumetric flow",
   "description": "Flow as % of the active Vmax (Vmax1 or Vmax2).",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 0.01,
   "units": "%",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 7,
   "documented": "8",
   "name": "Absolute volumetric flow (selected unit)",
   "description": "Unit set by No. 118.",
   "data_type": "UINT32",
   "length": 2,
   "word_order": "CDAB",
   "scale": 0.001,
   "units": "see No. 118",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 9,
   "documented": "10",
   "name": "Absolute volumetric flow (l/h)",
   "description": "",
   "data_type": "UINT32",
   "length": 2,
   "word_order": "CDAB",
   "scale": 0.001,
   "units": "l/h",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 11,
   "documented": "12",
   "name": "Absolute volumetric flow (gpm)",
   "description": "",
   "data_type": "UINT32",
   "length": 2,
   "word_order": "CDAB",
   "scale": 0.001,
   "units": "gpm",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 13,
   "documented": "14",
   "name": "Flow setpoint (selected unit)",
   "description": "Active absolute flow setpoint; unit set by No. 118.",
   "data_type": "UINT32",
   "length": 2,
   "word_order": "CDAB",
   "scale": 0.001,
   "units": "see No. 118",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 15,
   "documented": "16",
   "name": "Setpoint analog",
   "description": "Analog control voltage when Setpoint source = Analog.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 0.01,
   "units": "V",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 16,
   "documented": "17",
   "name": "Active sequence",
   "description": "",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "R",
   "values": {
    "0": "Sequence 1 (0-33 %)",
    "1": "Sequence 2 (67-100 %)",
    "2": "Dead band (34-66 %)"
   },
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 100,
   "documented": "101",
   "name": "Series number 1st part",
   "description": "First block of the serial number on the housing label.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 101,
   "documented": "102",
   "name": "Series number 2nd part",
   "description": "Second block of the serial number.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 102,
   "documented": "103",
   "name": "Series number 4th part",
   "description": "Fourth block of the serial number (the third is not exposed).",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 103,
   "documented": "104",
   "name": "Firmware version",
   "description": "Bus module firmware; 302 means version 3.02.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 104,
   "documented": "105",
   "name": "Malfunction and service information",
   "description": "Bit-coded fault flags; several can be set at once.",
   "data_type": "BITMAP16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "R",
   "values": null,
   "bits": {
    "2": "Error flow sensor",
    "3": "Actuator cannot move",
    "4": "Flow with closed valve",
    "5": "Air bubbles (runs in position control until cleared)",
    "6": "Flow not reached within 3 min",
    "9": "Gear disengaged"
   },
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 105,
   "documented": "106",
   "name": "Vmax sequence 1",
   "description": "Max flow for sequence 1, 5-100 %; default 100 %.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 0.01,
   "units": "%",
   "access": "RW",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 106,
   "documented": "107",
   "name": "Vmax sequence 2",
   "description": "Max flow for sequence 2, 5-100 %; default 100 %.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 0.01,
   "units": "%",
   "access": "RW",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 110,
   "documented": "111",
   "name": "Nominal volumetric flow (selected unit)",
   "description": "Vnom; unit set by No. 118.",
   "data_type": "UINT32",
   "length": 2,
   "word_order": "CDAB",
   "scale": 0.001,
   "units": "see No. 118",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 112,
   "documented": "113",
   "name": "Nominal volumetric flow (l/h)",
   "description": "",
   "data_type": "UINT32",
   "length": 2,
   "word_order": "CDAB",
   "scale": 0.001,
   "units": "l/h",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 114,
   "documented": "115",
   "name": "Nominal volumetric flow (gpm)",
   "description": "",
   "data_type": "UINT32",
   "length": 2,
   "word_order": "CDAB",
   "scale": 0.001,
   "units": "gpm",
   "access": "R",
   "values": null,
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 116,
   "documented": "117",
   "name": "Control mode",
   "description": "Default flow control.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "RW",
   "values": {
    "0": "Position control",
    "1": "Flow control"
   },
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 117,
   "documented": "118",
   "name": "Unit selection flow",
   "description": "Default l/h.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "RW",
   "values": {
    "0": "m3/s",
    "1": "m3/h",
    "2": "l/s",
    "3": "l/min",
    "4": "l/h",
    "5": "gpm",
    "6": "cfm"
   },
   "bits": null,
   "offset": 0
  },
  {
   "table": "holding_register",
   "address": 118,
   "documented": "119",
   "name": "Setpoint source",
   "description": "Analog = 0-10 V on wire 3; Bus = No. 1. Default Analog.",
   "data_type": "UINT16",
   "length": 1,
   "word_order": null,
   "scale": 1,
   "units": "",
   "access": "RW",
   "values": {
    "0": "Analog",
    "1": "Bus"
   },
   "bits": null,
   "offset": 0
  }
 ],
 "integration": {
  "summary": "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": [
   {
    "table": "holding_register",
    "address": 118,
    "why": "Setpoint source = Bus (default Analog)"
   },
   {
    "table": "holding_register",
    "address": 0,
    "why": "Setpoint across both sequences"
   },
   {
    "table": "holding_register",
    "address": 16,
    "why": "Active sequence"
   },
   {
    "table": "holding_register",
    "address": 9,
    "why": "Flow l/h"
   },
   {
    "table": "holding_register",
    "address": 4,
    "why": "Relative position"
   },
   {
    "table": "holding_register",
    "address": 104,
    "why": "Fault flags"
   }
  ],
  "enable": "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).",
  "watchdog": null,
  "quirks": [
   "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."
  ],
  "setup": [
   "Default frame 1-8-N-2 at 38400 baud.",
   "No built-in terminator: fit an external 120 ohm resistor at the bus ends."
  ],
  "gotchas": [
   "While air bubbles are detected the valve stays in position control whatever Control mode says (bit 5 of No. 105)."
  ]
 },
 "page": "https://easymodbus.com/modbus-register-maps/belimo/epiv-6-way",
 "address_note": "address = 0-based Modbus wire (PDU) address; documented = as printed in the source.",
 "note": "Re-typed from the manufacturer's public documentation (see source) and verified against it. Registers vary by firmware and options; verify against the live device before writing."
}