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Pump (vertical in-line with integrated VFD) · Modbus register map
Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2) Modbus register map
Updated 16 October 2026
Armstrong's Design Envelope in-line pumps carry an integrated drive and pump controller that speaks Modbus RTU on RS-485 or Modbus TCP over Ethernet. The register map gives speed, voltage, run status and I/O, the engineering units in use, control mode, hand/off/auto, speed limits, a BMS speed command and start/stop. Power, flow, head, current, counters and alarm words are 32-bit in the manual and are left out here because their word order is not documented.
This page lists 28 Modbus registers for the Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2) — 7 writable — with the table, 0-based wire address, data type, word order, scale, units and access of each, re-typed from Armstrong Fluid Technology’s own free documentation (linked below) and checked against it.
- Manufacturer
- Armstrong Fluid Technology
- Model
- Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2)
- Equipment type
- Pump (vertical in-line with integrated VFD)
- Registers
- 28 (7 writable)
- Transport
- Modbus RTU, Modbus TCP
- Default unit ID
- Not stated
- Documented addressing
- 1-based (subtract 1 for the wire address)
- Firmware
- Controller firmware v1.17 and newer
- Also known as
- Design Envelope 4300, Design Envelope 4380, DEPM IVS, DE IVS, Design Envelope pump controller, DEPC
Integration notes: Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2)
Select Modbus RTU or TCP/IP on the controller (touchscreen or web server) and set address, baud and parity/stop bits. Control is through HOA State (start address 301), BMS Set Speed (306) and Start/Stop (308); read actual speed (100/101), status (122) and control mode (300). Make sure the controller is set to BMS map version 2.
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 308 | Start/Stop | UINT16 | Start/stop | Read/write |
| HR 306 | BMS Set Speed | UINT16 | BMS speed command | Read/write |
| HR 301 | HOA State | UINT16 | Hand/Off/Auto | Read/write |
| HR 100 | Actual Speed (rpm) | UINT16 | Actual speed (rpm) | Read |
| HR 122 | Status | BITMAP16 | Run status | Read |
| HR 300 | Control Mode | UINT16 | Control mode | Read |
Enable Modbus control & writes
From the touchscreen or the web server (firmware v1.36), choose Modbus RTU or Modbus TCP/IP and enter the Modbus address, baud rate and parity/stop bits. In the web server's Remote mode setting, pick BMS map version 2 to match this register list.
Byte order & addressing
- The manual lists a 0-based start address next to a 1-based register number; use the start address on the wire.
- Many values are in the units chosen on the Pump Control Module; read the unit registers (start 250-254) before interpreting them.
- 32-bit values are not in this map because their word order is undocumented.
Network setup
- RS-485: connect the BMS cable to the controller board RS-485 port (A = +, B = -, G = ground); set the terminating-resistor switch to Enabled only on the first and last device of the daisy chain.
- Ethernet: connect the RJ-45 cable to the controller board.
- Select the protocol and enter address, baud and parity/stop bits on the touchscreen or web server.
Watch out for
- Check controller firmware first: the register map changed at v1.17.
- Control Mode (300) is read-only over Modbus in map version 2.
- The web server can switch the BMS register map between version 1 and version 2; the addresses here are version 2 only.
Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2) 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 | 100doc 101 | Actual Speed (rpm) | Current VFD speed. | UINT16 | rpm | Read | |||
| HR | 101doc 102 | Actual Speed (%) | Current speed as % of nominal motor speed. | UINT16 | × 0.1 | % | Read | ||
| HR | 104doc 105 | Motor Input Voltage | Voltage the drive delivers to the motor. | UINT16 | × 0.1 | V | Read | ||
| HR | 115doc 116 | Number of Running Pumps | Parallel sensorless mode. | UINT16 | Read | ||||
| HR | 122doc 123 | Status | Pump run status. | BITMAP16 | Read | bit 0 = Pump rotating | |||
| HR | 200doc 201 | Digital In | Digital input states. | BITMAP16 | Read | bit 0 = Digital input 1; bit 1 = Digital input 2 | |||
| HR | 205doc 206 | Analog Out 1 | UINT16 | × 0.01 | mA | Read | |||
| HR | 206doc 207 | Digital Out | Digital output states. | BITMAP16 | Read | bit 0 = Digital output 1; bit 1 = Digital output 2 | |||
| HR | 207doc 208 | Relays | Relay states. | BITMAP16 | Read | bit 0 = Relay 1; bit 1 = Relay 2 | |||
| HR | 250doc 251 | Flow Units | Unit used by flow values. | UINT16 | Read | 1 = l/s; 2 = m³/h; 3 = g/m | |||
| HR | 251doc 252 | Pressure Units | Unit used by head/pressure values. | UINT16 | Read | 1 = bar; 2 = kPa; 3 = psi; 4 = ft; 5 = m | |||
| HR | 252doc 253 | Power Units | Unit used by power values. | UINT16 | Read | 1 = kW; 2 = hp | |||
| HR | 253doc 254 | Speed Units | Unit used by hand-mode and BMS speed. | UINT16 | Read | 1 = rpm; 2 = % | |||
| HR | 254doc 255 | Temperature Units | UINT16 | Read | 1 = Degrees Celsius; 2 = Degrees Fahrenheit | ||||
| HR | 300doc 301 | Control Mode | Active control mode (read only). | UINT16 | Read | 1 = Parallel; 2 = Inputs; 3 = Remote; 4 = Constant Flow; 5 = Constant Pressure; 6 = Linear Pressure; 7 = Quadratic Pressure; 8 = Quad Pressure Maximum; 9 = Quad Pressure Minimum; 10 = Quadratic Pressure Max/Min | |||
| HR | 301doc 302 | HOA State | Hand / off / auto selection. | UINT16 | Read/write | 0 = Off; 1 = Hand; 2 = Auto | |||
| HR | 302doc 303 | Active Parameters | Which parameter set is active. | UINT16 | Read/write | 1 = Standard; 2 = Mode 1 (heating); 3 = Mode 2 (cooling) | |||
| HR | 303doc 304 | Minimum Speed Limit | UINT16 | rpm | Read/write | ||||
| HR | 304doc 305 | Maximum Speed Limit | UINT16 | rpm | Read/write | ||||
| HR | 305doc 306 | Hand Mode Speed | Hand-mode speed, 0.1 resolution, in the controller's configured speed unit (see register 254). | UINT16 | × 0.1 | Read/write | |||
| HR | 306doc 307 | BMS Set Speed | Speed command from the BMS, 0.1 resolution, in the configured speed unit (see register 254). | UINT16 | × 0.1 | Read/write | |||
| HR | 308doc 309 | Start/Stop | Start or stop the pump. | UINT16 | Read/write | 0 = Stop; 1 = Start | |||
| HR | 900doc 901 | Pump Name / Tag name | Pump tag as ASCII text. | STRING[16] | Read | ||||
| HR | 908doc 909 | Serial Number | Pump serial number as ASCII text. | STRING[14] | Read | ||||
| HR | 915doc 916 | Firmware Version | Controller firmware major.minor (divide by 100). | UINT16 | × 0.01 | Read | |||
| HR | 916doc 917 | Hardware Version | Pump Control Module hardware version. | UINT16 | Read | ||||
| HR | 917doc 918 | BMS Modbus Version | Version of the Armstrong Modbus register map. | UINT16 | Read | ||||
| HR | 918doc 919 | Firmware Patch Version | Firmware patch number, appended to the firmware version. | UINT16 | Read |
Notes on this map
- Only function codes 03 (read) and 06 (write single) are listed in the map.
- Left out because the manual does not state the 32-bit word order: Motor Power, Motor Input Current, Sensorless Head/Flow, Total Flow/Power, Max Sensorless Flow/Head, Analog In 1/2, the running-hour and kWh counters, the Alarms/Warnings/Acknowledge Warnings bit fields, the mode parameter sets (500-523) and Control Setpoint (539). All are 2-register UINT32 values in the manual; add them only once the word order is confirmed.
- Firmware v1.16 and older use a different register map (version 1, manual p. 24-25); it is not covered here.
- Hand Mode Speed and BMS Set Speed have 0.1 resolution in the unit configured on the controller; the Speed Units register (254) reports whether that is rpm or %. Minimum/Maximum Speed Limit are plain rpm.
- Strings: Pump Name occupies 8 registers and Serial Number 7 registers of ASCII; byte order within each register is not stated.
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 Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2)
What Modbus registers does the Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2) have?
This map lists 28 registers: 28 holding registers. 7 of them can be written. Registers vary with firmware, options and configuration, so confirm against the device.
Are the Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2) 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. The manual prints both a 0-based 'start address' and a 1-based 'Modbus register' for every entry (e.g. Actual Speed start address 100, Modbus register 101). The register number is kept as 'documented'; the start address is the wire address.
What are the minimum Modbus registers to integrate the Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2)?
Start with HR 308 Start/Stop (Start/stop); HR 306 BMS Set Speed (BMS speed command); HR 301 HOA State (Hand/Off/Auto); HR 100 Actual Speed (rpm) (Actual speed (rpm)); HR 122 Status (Run status); HR 300 Control Mode (Control mode).
How do I enable Modbus control of the Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2)?
From the touchscreen or the web server (firmware v1.36), choose Modbus RTU or Modbus TCP/IP and enter the Modbus address, baud rate and parity/stop bits. In the web server's Remote mode setting, pick BMS map version 2 to match this register list.
Where is the official Armstrong Fluid Technology Design Envelope 4300 / 4380 with DEPM IVS / DE IVS drive (map v2) Modbus documentation?
The source is Design Envelope 4300 & 4380 Vertical In-line pumping unit with DEPM IVS and DE IVS drive - Installation and operating instructions (101.82iec), revision 2025-11-10, published free by Armstrong Fluid Technology at https://armstrongfluidtechnology.com/~/media/documents/installation_maintenance_parts/installation-and-operating-instructions/101-82_de_4300-4380_vil_withivsdrive_io.pdf?la=en-gb.
Source: Design Envelope 4300 & 4380 Vertical In-line pumping unit with DEPM IVS and DE IVS drive - Installation and operating instructions · 101.82iec · rev. 2025-11-10. Register numbers, types, scaling and units are reproduced as published; descriptions are our own.