ENM-223-R1 Energy Metering

Overview

The ENM-223-R1 is a configurable smart I/O module designed for 3-phase power quality and energy metering. It includes 3 voltage inputs, 3 current channels (CTs), 2 SPDT relays, 4 buttons, and 4 LEDs, with configuration via USB-C WebConfig and communication via RS-485 (Modbus RTU). It connects to a MicroPLC/MiniPLC for use in energy monitoring, automation, and smart building applications.

Getting Started

Quick Setup Process

1. Mount & Wire – Install on 35mm DIN rail, connect 24V DC power, sensors, and relay loads.

2. Configure – Plug in USB-C, open the WebConfig tool in Chrome/Edge, set Modbus address and I/O mapping.

3. Integrate – Connect to your controller via RS-485 and start automation.

What You Need

• ENM-223-R1 module

• 24V DC SELV power supply

• RS-485 cable (twisted pair)

• USB-C cable for configuration

• Chromium browser (Chrome/Edge)

Web Configuration Steps

1. Connect USB-C to module and PC

2. Open https://www.home-master.eu/configtool-enm-223-r1

3. Click "Connect" and select serial port

4. Set Modbus address (default: 3) and baud rate (default: 19200 8N1)

5. Configure input actions, mapping, LED modes, and button functions

6. Settings save automatically to flash

Tech Specs

Documentation

The ENM-223-R1 is open-source hardware! You can build your own board using the following files:

Hardware Design Files

• Field Board Schematic: ENM-223-R1-FieldBoard.pdf

• MCU Board Schematic: ENM-223-R1-MCUBoard.pdf

• System Block Diagram: ENM_SystemBlockDiagram.png

• Field Board Diagram: FieldBoard_Diagram.png

• MCU Board Diagram: MCUBoard_Diagram.png

Firmware & Software

• Firmware Source Code: ENM-223-R1/Firmware/

• WebConfig Tool: ConfigToolPage.html

• ESPHome Integration Package: default_enm_223_r1_plc.yaml

Mechanical Files:

• Dimensional Drawing: ENMDimensions.png

All design files and documentation are available in the HomeMaster GitHub repository.

Input and Output

Voltage & Current Inputs:

• 3 voltage channels (L1/L2/L3–N)

• 3 CT inputs (external split-core CTs)

• Isolated measurement via ATM90E32AS metering IC

• Configurable gains/offsets via WebConfig

Relay Outputs (2 channels):

• SPDT contacts (NO/NC/COM)

• 5A @ 250V AC rating

• Controlled via Modbus coils or alarm logic

• RC/TVS snubbers recommended for inductive loads

User Interface:

• 4 Buttons: Configurable for relay override, toggle, alarm acknowledgment

• 4 LEDs: Configurable steady or blink modes, linked to alarms/overrides

• Status LEDs: PWR (power), TX/RX (Modbus activity)

Communication Interfaces

• Protocol: Modbus RTU

• Role: Slave device

• Default Settings: Address 3, 19200 baud, 8 data bits, No parity, 1 stop bit

• Supported Functions: Read Coils (0x01), Read Discrete Inputs (0x02), Read Holding Registers (0x03), Read Input Registers (0x04), Write Single Coil (0x05), Write Single Register (0x06)

Modbus Address Map

Coils (Read/Write) – Function Codes 0x01, 0x05

Discrete Inputs (Read Only) – Function Code 0x02

Holding Registers (Read/Write) – Function Codes 0x03, 0x06, 0x10

Input Registers (Read Only) – Function Code 0x04

Home Assistant & ESPHome Integration Guide

Overview

The ENM-223-R1 integrates seamlessly with Home Assistant via ESPHome using the Modbus RTU protocol. This guide covers both quick integration using our pre-built package and manual configuration for advanced users.

Prerequisites

Before starting, ensure you have:

1. ESPHome device (HomeMaster MiniPLC/MicroPLC or any ESP32/ESP8266 with RS-485)

2. RS-485 connection between ESP device and ENM-223-R1

3. 24V power to ENM-223-R1 module

4. Home Assistant with ESPHome add-on installed

RS‑485 Configuration

uart:
  id: uart_modbus
  tx_pin: GPIO17
  rx_pin: GPIO16
  baud_rate: 19200
  parity: NONE
  stop_bits: 1

modbus:
  id: modbus_bus
  uart_id: uart_modbus

Import ENM-223-R1 Package:

packages:
  enm_223_r1:
    url: https://github.com/isystemsautomation/HOMEMASTER
    ref: main
    files:
      - path: ENM-223-R1/Firmware/default_enm_223_r1_plc.yaml
    vars:
      enm_prefix: "Main Panel"  # Custom name for your entities
      enm_id: main_module       # Unique internal ID
      enm_address: 3            # Must match WebConfig Modbus address
      refresh: 1d

Customize Variables:

• enm_prefix: Appears in entity names (e.g., "Main Panel Voltage L1")

• enm_id: Internal identifier for the module

• enm_address: Modbus address (must match WebConfig setting)

Example with Multiple ENMs:

packages:
  enm_main:
    url: https://github.com/isystemsautomation/HOMEMASTER
    ref: main
    files:
      - path: ENM-223-R1/Firmware/default_enm_223_r1_plc.yaml
    vars:
      enm_prefix: "Main Panel"
      enm_id: main_module
      enm_address: 3
      refresh: 1d

  enm_solar:
    url: https://github.com/isystemsautomation/HOMEMASTER
    ref: main
    files:
      - path: ENM-223-R1/Firmware/default_enm_223_r1_plc.yaml
    vars:
      enm_prefix: "Solar"
      enm_id: solar_module
      enm_address: 4
      refresh: 1d

Programming

Supported Development Environments

• Arduino IDE with RP2350 support

• PlatformIO with RP2350 toolchain

• MicroPython (community builds available)

Firmware Flashing

1. Connect USB-C to PC

2. Hold Buttons 3 + 4 to enter BOOT mode

3. Hold Buttons 1 + 2 to RESET the module

4. Upload via:

   • UF2 drag-and-drop to mounted drive, OR

   • PlatformIO/Arduino IDE upload

Pin Mapping (Default Firmware)