homemaster-dev

🚧 Project Status: Under Active Development & Testing

Important Notice: This documentation, hardware designs, and firmware are for the pre-release version of the HomeMaster system. All information is preliminary and may contain errors or be subject to change.

Please use this information for evaluation and development purposes only.

Firmware Version: 2025-10 snapshot

Firmware Version Modbus License

DIO-430-R1 — Module for Smart I/O Control

HOMEMASTER – Modular control. Custom logic.

MODULE photo

1. Introduction

The DIO-430-R1 is a configurable smart digital I/O module designed for digital input monitoring and relay-based output control in building automation, lighting, HVAC, alarms, and general control systems.
It offers 4 opto-isolated digital inputs, 3 high-current SPDT relays, 3 user buttons, and 3 configurable user LEDs. All I/O channels are individually configurable, allowing flexible logic such as toggle, pulse, manual override, and alarm indication.

It connects via RS-485 (Modbus RTU) to a MicroPLC, MiniPLC, or any compatible controller, and can also integrate with Home Assistant (ESPHome) or SCADA/PLC systems.
Configuration and diagnostics are performed through a driverless Web Serial interface via USB-C, using the browser-based WebConfig Tool. The module supports both master-controlled and standalone local logic modes.

Subsystem Qty Description
Digital Inputs 4 Opto-isolated, dry contact compatible, noise-protected
Relays 3 SPDT (NO/NC), 16 A rated, dry contacts
LEDs 3 Configurable: Steady or Blink modes, linked to relays
Buttons 3 User-configurable for override or reset
Modbus RTU Yes RS-485 interface (Configurable: Addr 1–255, 9600–115200 baud)
USB-C Yes WebConfig tool access via Web Serial (Chrome/Edge)
Power 24 V DC Fused input, reverse-polarity and surge protected
MCU RP2350 Dual-core, with QSPI flash, USB, UART, LittleFS
Protection TVS, PTC ESD, surge, and short-circuit protection on I/O and power

System Role & Communication

The module communicates over the RS-485 Modbus RTU bus, using A/B differential lines and a shared COM/GND reference. It supports poll-based communication, where a master device reads input states and writes relay commands.
All configuration — including input-to-relay mapping, LED modes, and button logic — is stored persistently in internal flash via LittleFS and can be changed live through USB-C + WebConfig.

Factory default communication settings:

The module’s logic (input→relay mapping, LED modes, button behavior) is stored persistently in internal flash via LittleFS, and settings can be changed live using USB-C + WebConfig.

2. DIO-430-R1 — Technical Specification

2.1 Diagrams & Pinouts

System overview, board callouts, and pin mapping:

2.2 I/O and Electrical Summary

Interface Qty Description
Digital Inputs 4 Galvanically isolated (ISO1212 class). Supports dry contacts or 24 V signals. PTC + TVS per channel.
Relay Outputs 3 SPDT (NO/NC/COM), 16 A dry contacts. Use RC/MOV snubbers or interposing contactors for inductive/mains loads.
User LEDs 3 Configurable (Steady/Blink). Follow relay or logic status.
Buttons 3 Momentary. Configurable for relay override/toggle.
RS-485 (Modbus RTU) 1 A/B/COM terminals. Daisy-chain topology. 120 Ω termination at both ends.
USB-C 1 Web Serial setup, diagnostics, and firmware flashing (ESD-protected).
Power Input 1 24 V DC SELV. Reverse-polarity + surge protected.

Electrical Ratings

Parameter Min Typ Max Unit Notes
Supply Voltage 22 24 28 V DC SELV/PELV input
Logic Consumption – 1.5 3.0 W Excludes relay loads
Digital Input Range 0 24 30 V DC Isolated, noise-protected
Relay Contact Current – – 16 A SPDT dry contacts
Relay Contact Voltage – – 250 V AC or 30 V DC max
RS-485 Data Rate – 19.2 115.2 kbps Default 19200 8N1
USB-C Voltage 4.75 5.0 5.25 V DC Service only
Operating Temp. 0 – 40 °C ≤ 95 % RH, non-condensing

Power budgeting: logic + LEDs + up to 3 relay coils + sensor loads → add ≥ 30 % PSU headroom.

2.3 Connectors & Terminal Map

Block Pins Function Notes
POWER 0V, V+ 24 V DC input Reverse/surge protected
RELAY 1-3 NO, C, NC SPDT contacts Add RC/MOV for inductive loads
DI 1-4 INx, GNDx Isolated digital inputs 24 V field or dry contact
RS-485 B, A, COM Modbus RTU bus Terminate 120 Ω at ends
USB-C D+, D−, VBUS, GND Setup / Service port Not for field powering

2.4 Reliability & Protection

2.5 Functional Overview

2.6 Mechanical & Environmental

Property Specification
Mounting DIN-rail EN 50022 (35 mm)
Enclosure PC/ABS V-0, panel mount
Dimensions 70 × 90.6 × 67.3 mm (W × H × D)
Terminals Pluggable 5.08 mm, 26–12 AWG (≤ 2.5 mm²), 0.5–0.6 Nm
Ingress Protection IP20 (panel interior)
Operating Temp 0–40 °C, ≤ 95 % RH (non-condensing)

DIO-430-R1 Dimensions

2.7 Standards & Compliance

Standard / Directive Description
Ingress Rating IP20 (panel-mount only)
Altitude ≤ 2000 m
Environmental RoHS / REACH compliant components

3. Use Cases

The DIO‑430‑R1 supports both lighting and motor/pump control — making it ideal for mixed automation tasks in smart homes, greenhouses, HVAC, and industrial setups.
Below are 3 versatile examples combining both types of loads.

3.1 Staircase Light with Motion Sensor + Circulation Pump

Automatically turns ON a staircase light and a circulation pump when motion is detected.

Setup Instructions:

3.2 Manual Light + Fan Override (Wall Panel)

Wall-mounted buttons allow users to toggle lights and exhaust fans independently.

Setup Instructions:

3.3 Greenhouse Light + Irrigation Pump Automation

Lights and irrigation are controlled via digital inputs or remotely from a PLC.

Setup Instructions:

4. Safety Information

These guidelines apply to the DIO-430-R1 I/O module. Ignoring them may result in equipment damage, system failure, or personal injury.

⚠️ SELV/PELV Domains Only

4.1 General Requirements

Requirement Detail
Qualified Personnel Installation and servicing must be done by qualified personnel familiar with 24 V control systems and RS-485.
Power Isolation Disconnect the 24 V DC input before wiring. Lockout/tagout where applicable.
Environmental Limits Mount in a clean, sealed enclosure; avoid condensation, conductive dust, or vibration.
Grounding Bond the panel to PE. Keep RS-485 COM/GND shared with the controller side.
Voltage Compliance SELV only on all terminals. Follow relay contact ratings on the product label/datasheet. Use upstream fusing and surge protection.

4.2 Installation Practices

Task Guidance
ESD Protection Handle by the enclosure/edge only. Use an antistatic wrist strap when the board is exposed.
DIN Rail Mounting Mount securely on 35 mm DIN rail inside an IP-rated cabinet. Leave cable slack for strain relief.
Wiring Use correct wire gauge and torque terminal screws. Separate power, DI, relay, and RS-485 harnesses.
Isolation Domains Respect isolation: do not bridge logic GND to isolated field grounds (e.g., GND_ISO/FGND). Keep analog/sensor returns on the isolated side.
Commissioning Before power-up, verify polarity, relay NO/NC routing, RS-485 A/B orientation and termination.

4.3 I/O & Interface Warnings

🔌 Power

Area Warning
24 V DC Input Use a clean, fused SELV supply. Reverse-polarity protection exists but may disable the module when triggered.
Sensor Rail Power sensors from a SELV rail. Observe polarity. Fuse external branches as required.
Surge/Noise In noisy panels, add upstream surge/EMI suppression and keep high-current wiring away from control wiring.

⏽ Inputs (Digital)

Area Warning
Type Dry contact / 24 V signaling only, per your standard. Do not inject mains or undefined levels.
Isolation Inputs are isolated from logic. Keep sensor returns on the field/isolated domain; do not bond to logic GND.
Debounce Firmware provides debounce, but route away from contactors/VFDs and use shielded/twisted pairs for long runs.
Polarity Configure invert/action in WebConfig; verify state transitions after wiring.

⚙️ Relays (Outputs)

Area Warning
Contact Type SPDT (NO/NC/COM) dry contacts. Follow the contact rating on the device label/datasheet.
Inductive Loads For motors/solenoids/contactors, add an RC snubber or MOV at the load. Consider interposing relays/ contactors for higher power.
Separation Keep relay load wiring physically separate from signal wiring. De-energize before servicing.
Verification After wiring, verify NO/NC behavior and load polarity before enabling automation.

🖧 RS-485 (Modbus RTU)

Area Warning
Topology Use twisted pair; daisy-chain (no stubs). Terminate with 120 Ω at both physical ends.
Polarity Maintain A/B polarity consistently. Share COM/GND reference between nodes (same SELV domain).
EMC Route away from VFDs, contactors, and mains bundles. Use shielded cable in high-EMI environments.
Protection Port includes protection, but good wiring practice is still required to avoid transients.

🔌 USB-C (Front / Setup)

Area Warning
Purpose Setup & maintenance only (WebConfig / firmware). Not intended for powering field devices.
ESD/EMI Avoid hot-plugging in high-EMI areas. Use a grounded service laptop. Disconnect after commissioning.

🔆 Front Panel (Buttons & LEDs)

Area Warning
Buttons & LEDs Buttons can override relays; document operating procedures. Lock out overrides for safety-critical installs.

🛡️ Shielding & EMC

Area Recommendation
Cable Shields Terminate shields at one end (typically the PLC/controller). Keep runs short and away from high-voltage/EMI sources.

✅ Pre-Power Checklist

5. Installation & Quick Start

The DIO-430-R1 joins your system over RS-485 (Modbus RTU). Setup has two parts:
1) Physical wiring, 2) Digital configuration (WebConfig → optional PLC/ESPHome).

5.1 What You Need

Category Item / Notes
Hardware DIO-430-R1 — DIN-rail module with 4× DI, 3× SPDT relays, 3× buttons, 3× LEDs, USB-C, RS-485.
Controller (master) HomeMaster MiniPLC/MicroPLC or any Modbus RTU master.
24 VDC PSU (SELV) Regulated 24 VDC; size for logic + relay coils + sensors; inline panel fuse/breaker. Power input stage includes fuse/TVS/reverse-polarity protection.
RS-485 cable Twisted pair for A/B + COM/GND reference, 120 Ω termination at both ends of the trunk.
USB-C cable For WebConfig via a Chromium browser (service/commissioning).
Software Chromium-based browser with Web Serial (Chrome/Edge). Web page exposes Address/Baud + I/O mapping.
Field I/O Dry contacts to DI1…DI4 (isolated front-end per channel). Relays (NO/NC/COM) drive LV loads or interposing contactors; add RC/MOV snubbers for inductive loads.

Quick path: mount → wire 24 VDC + RS-485 A/B/COM → connect USB-C → WebConfig: set Address/Baud + map inputs → relays/LEDs → disconnect USB → hand over to controller.

5.2 Power

The module uses 24 VDC primary. Onboard regulation provides 5 V → 3.3 V for logic; DI front-end is isolated.

5.2.1 Supply Types

5.2.2 Sizing (rule of thumb)

Account for:

Size PSU for worst-case relays + sensors, then add ≥30 % headroom.

5.2.3 Power Safety

5.3 Networking & Communication

Runtime control is via RS-485 (Modbus RTU). USB-C is for local setup/diagnostics (Web Serial).

5.3.1 RS-485 (Modbus RTU)

Physical

Protocol

Checklist

5.3.2 USB-C (WebConfig)

Purpose: Chromium (Chrome/Edge) Web Serial setup/diagnostics page.

Steps

  1. Connect USB-C to the module.
  2. Open the DIO-430-R1 WebConfig page and click Connect.
  3. Set Modbus Address & Baud (header shows Active Modbus Configuration).
  4. Configure Inputs / Relays / LEDs / Buttons; changes apply live and are saved to flash.
  5. Use Reset Device from the page if needed (dialog confirms).

If Connect is disabled: ensure Chromium + serial permission; close other apps that might hold the port.

5.4 Installation & Wiring

This section shows typical wiring for power, inputs, relays, RS-485, and the USB-C service port.

⚠️ Work on de-energized equipment only. Use SELV/PELV supplies for logic and field inputs. Mains on relay contacts must be wired by qualified personnel.

A) Power — 24 VDC (SELV)

Wire the regulated 24 VDC supply to the top POWER terminals: V+ and 0V.

24Vdc wiring

Notes

B) Digital Inputs (DI1…DI4)

Each input is isolated. Land the contact/sensor on INx with the paired GNDx return.

Digital inputs

Tips

C) Relay Outputs (R1…R3)

Relays provide dry SPDT contacts (NO/NC/COM) for switching low-voltage loads or driving an interposing contactor for mains/inductive loads.

Relay wiring example

Best practices

D) Sensor Rails (12 V / 5 V)

This module does not export auxiliary 12 V/5 V rails for field devices.

E) RS-485 (Modbus RTU)

The lower left terminals expose B, A, and COM (GND). Use shielded twisted pair and daisy-chain topology.

RS-485 connection

Checklist

F) USB-C (Service / WebConfig)

5.5 Software & UI Configuration

Use the WebConfig page (USB-C + Chrome/Edge) to set Modbus comms and map I/O. Changes apply immediately and are saved to flash.

Screens shown below are from the DIO-430-R1 WebConfig.

WebConfig — Header & Modbus

A) WebConfig setup (Address & Baud)

  1. Connect the module via USB-C → open the WebConfig page → click Connect.
  2. In Modbus Address, choose 1–255 (factory default 3).
  3. In Baud Rate, select 9600–115200 (factory default 19200 8N1).
  4. Confirm the Active Modbus Configuration banner updates (Address/Baud).

Default values (Addr 3, 19200 8N1) are also noted in the module docs.

WebConfig — Digital Inputs

B) Inputs — enable / invert / group (control target)

Each IN1…IN4 card provides:

This matches the firmware’s input options and allows direct mapping from inputs to one or more relays without a PLC.

Tips

WebConfig — Relays, Buttons, LEDs

C) Relays — logic mode (group/manual)

For Relay 1–3:

Logic modes in practice

D) LED and Button mapping

Buttons (3)

User LEDs (3)

5.6 Getting Started (3 Phases)

Phase 1 — Wire

Phase 2 — Configure (WebConfig)

Phase 3 — Integrate (Controller)

✅ Verify

| Area | What to Check | |—|—| | LEDs | PWR = ON; TX/RX blink during RS-485 traffic | | Inputs | Toggling a wall switch/sensor changes INx state in WebConfig/Modbus | | Relays | Coil writes toggle R1–R3; loads switch correctly; snubber installed for inductive loads | | Address/Baud | Controller reads module at the configured address/baud without errors | | Isolation | No unintended bond between logic GND and DI field GNDx |

6. Modbus RTU Communication

Role: RTU slave (controller is master)
Defaults: Address 3, 19200 8N1 (change in WebConfig → Modbus)

Addressing shown below uses zero-based offsets (e.g., Holding Reg 40000 = offset 0).
If your master uses 1-based display (e.g., 40001), add +1 to the register number.

6.1 Address Range & Map (Overview)

Type Range (offsets) Purpose
Coils (0x) 00000…00031 Relay commands, device control
Discrete Inputs (1x) 10000…10031 DI states, relay echo states
Input Registers (3x) 30000…30031 Read-only status (masks, counters)
Holding Registers (4x) 40000…40063 Config & runtime parameters (DI actions/targets, relay/LED/button settings, comms)

6.2 Coils (0x) — Commands

Coil Name Description
00000 R1_CMD Relay 1 ON/OFF (write 1/0)
00001 R2_CMD Relay 2 ON/OFF
00002 R3_CMD Relay 3 ON/OFF
00010 SAVE_CFG Persist current settings to flash (write 1)
00011 RESET Soft reset device (write 1)

Coils drive relays regardless of input mappings (local buttons still work as overrides).

6.3 Discrete Inputs (1x) — States

DI Name Description
10000 DI1_STATE Digital Input 1 (after invert option)
10001 DI2_STATE Digital Input 2
10002 DI3_STATE Digital Input 3
10003 DI4_STATE Digital Input 4
10010 R1_STATE Relay 1 actual state (echo)
10011 R2_STATE Relay 2 actual state
10012 R3_STATE Relay 3 actual state

6.4 Holding Registers (4x) — Configuration & Runtime

6.4.1 Identity / Comms

Reg Name R/W Encoding Notes
40000 MODEL_ID R u16 e.g., 0x0430 (DIO-430)
40001 FW_BUILD R YYYYMM Snapshot / build tag
40002 MB_ADDR R/W u16 1…255
40003 MB_BAUD R/W enum 0=9600,1=19200,2=38400,3=57600,4=115200
40004 MB_PARITY R/W enum 0=None,1=Even,2=Odd (default 0)

6.4.2 Digital Inputs (per-channel)

Action codes: 0=None, 1=Toggle (latched), 2=Pulse (momentary)
Target codes: 4=None, 0=Control all, 1=R1, 2=R2, 3=R3

Reg Name R/W Encoding Notes
40010 DI_EN_MASK R/W bitmask bit0..3 → IN1..IN4 enable
40011 DI_INV_MASK R/W bitmask bit0..3 → IN1..IN4 invert
40012 DI1_ACTION R/W u16 enum 0/1/2
40013 DI2_ACTION R/W u16 enum 0/1/2
40014 DI3_ACTION R/W u16 enum 0/1/2
40015 DI4_ACTION R/W u16 enum 0/1/2
40016 DI1_TARGET R/W u16 enum 4/0/1/2/3
40017 DI2_TARGET R/W u16 enum 4/0/1/2/3
40018 DI3_TARGET R/W u16 enum 4/0/1/2/3
40019 DI4_TARGET R/W u16 enum 4/0/1/2/3

6.4.3 Relays / Buttons / LEDs

Reg Name R/W Encoding Notes
40020 RLY_EN_MASK R/W bitmask bit0..2 → R1..R3 enable
40021 RLY_INV_MASK R/W bitmask invert coil logic (rarely used)
40022 BTN1_ACTION R/W u16 enum 0=None, 5=R1 toggle, 6=R2 toggle, 7=R3 toggle
40023 BTN2_ACTION R/W u16 enum as above
40024 BTN3_ACTION R/W u16 enum as above
40025 LED_MODE R/W bit-packed bits0..1 = LED1 (0=Steady,1=Blink), bits2..3 = LED2, bits4..5 = LED3

6.4.4 Status / Diagnostics

Reg Name R/W Encoding Notes
40030 UPTIME_S_LO R u16 lower 16 bits
40031 UPTIME_S_HI R u16 upper 16 bits (32-bit seconds)
40032 ERR_CODE R u16 0=OK; non-zero = last error
40033 FLAGS R bitmask e.g., cfg-dirty, wd-reset (implementation-specific)

Note: All configuration is usually done via WebConfig. The registers above are provided to enable controller-side provisioning and telemetry when needed.

6.5 Input Registers (3x) — Convenience (Read-only)

Reg Name Encoding Description
30000 DI_STATE_MASK bitmask bit0..3 → IN1..IN4 (post-invert)
30001 RLY_STATE_MASK bitmask bit0..2 → R1..R3
30002 BTN_STATE_MASK bitmask bit0..2 → B1..B3 (momentary)
30003 LED_STATE_MASK bitmask bit0..2 → LED1..LED3 active

6.6 Register Use Examples

A) Toggle a relay from a PLC

  1. Write 1 to Coil 00001 (R2_CMD) → Relay 2 ON
  2. Write 0 to the same coil → Relay 2 OFF

B) Map IN3 to drive Relay 1 as a latched toggle

  1. 40010 (DI_EN_MASK) → set bit2 = 1 (enable IN3)
  2. 40011 (DI_INV_MASK) → set bit2 = 0 (no invert)
  3. 40014 (DI3_ACTION) → write 1 (Toggle)
  4. 40018 (DI3_TARGET) → write 1 (R1)

C) Set Button 2 to local override of Relay 2

E) Change Modbus address & baud from the master

6.7 Polling Recommendations

7. ESPHome Integration Guide (MiniPLC/MicroPLC + DIO-430-R1)

Support status: ✔️ Supported via ESPHome uart + modbus + modbus_controller and a reusable package.
Module role: Modbus RTU slave on RS-485.
Defaults: Address 3, 19200 8N1 (change in WebConfig).

7.1 Minimal YAML (Controller side)

Use this on the MiniPLC/MicroPLC (ESPHome). It enables the RS-485 bus and imports a ready-made DIO package.

uart:
  id: uart_modbus
  tx_pin: 17
  rx_pin: 16
  baud_rate: 19200
  parity: NONE
  stop_bits: 1

modbus:
  id: modbus_bus
  uart_id: uart_modbus

packages:
  dio1:
    url: https://github.com/isystemsautomation/homemaster-dev
    ref: main
    files:
      - path: DIO-430-R1/Firmware/default_dio_430_r1_plc/default_dio_430_r1_plc.yaml
        vars:
          dio_prefix: "DIO#1"  # shown in Home Assistant entity names
          dio_id: dio_1        # internal unique id
          dio_address: 4       # Modbus address set in WebConfig for this DIO
    refresh: 1d

For multiple DIOs, duplicate the dio1: block (dio2:, dio3:…) with unique dio_id, dio_prefix, and dio_address.

7.2 Entities exposed (from the package)

The package sticks to the Modbus map defined in Section 6 (coils for relays, discrete inputs for DI states, holding/input registers for masks and configuration).

7.3 Optional: direct (manual) entity mapping

If you prefer not to use the package, you can expose the core points directly:

modbus_controller:
  - id: dio430_4
    address: 4
    modbus_id: modbus_bus
    update_interval: 200ms
    command_throttle: 100ms

binary_sensor:
  # DI1..DI4 as Discrete Inputs (1x offsets 0..3)
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 DI1"
    register_type: discrete_input
    address: 0
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 DI2"
    register_type: discrete_input
    address: 1
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 DI3"
    register_type: discrete_input
    address: 2
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 DI4"
    register_type: discrete_input
    address: 3

switch:
  # Relays as Coils (0x offsets 0..2)
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 Relay 1"
    register_type: coil
    address: 0
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 Relay 2"
    register_type: coil
    address: 1
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 Relay 3"
    register_type: coil
    address: 2

sensor:
  # (Optional) LED and Button masks from Input Registers 30003/30002
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 LED Mask"
    register_type: input
    address: 3
    value_type: U_WORD
    accuracy_decimals: 0
  - platform: modbus_controller
    modbus_controller_id: dio430_4
    name: "DIO#1 Button Mask"
    register_type: input
    address: 2
    value_type: U_WORD
    accuracy_decimals: 0

7.4 Home Assistant tips (dashboards & automations)

7.5 Troubleshooting

7.7 Notes & Versions

8. Programming & Customization (DIO-430-R1)

8.1 Supported Languages

8.2 Flashing (USB‑C, Hardware Buttons Only)

The module exposes a USB device for flashing. All reset/boot actions are done with the front buttons in hardware.

Button layout (front panel):

Button Layout 1‑2‑3

Combinations

Steps (UF2/IDE)

  1. Connect USB‑C to a PC (disconnect RS‑485 during flashing).
  2. Hold Buttons 2 + 3 to enter BOOT. The board appears as a USB drive (UF2) or a serial device for IDE upload.
  3. Flash:
    • UF2: drag‑and‑drop the new .uf2 file onto the mounted drive; the module restarts automatically.
    • PlatformIO / Arduino IDE: select the correct board/port and upload.
  4. If needed, press Buttons 1 + 3 for a hardware RESET.

No factory‑reset function is provided. Configuration remains intact across normal firmware updates.

8.3 Arduino / PlatformIO Notes

Board / Toolchain

Required Libraries (typical firmware)

Pin Mapping (DIO-430-R1 default firmware)

Build Tips

8.4 Firmware Updates

9. Maintenance & Troubleshooting

9.1 Status LEDs (typical)

9.2 Resets

9.3 Common Issues

Symptom Checks
No Modbus comms A/B polarity, COM/GND reference, 120 Ω termination, address/baud match, only two end terminators
Relays don’t actuate Relay Enabled in WebConfig, no active Override holding state, coil invert setting, Modbus coil writes acknowledged
DI not changing Wire to INx/GNDx (isolated field side), check Enable/Invert/Action/Target in WebConfig, debounce expectations
USB won’t connect Chrome/Edge with Web Serial, close other serial apps, check cable/port permissions
Config not saved Allow idle for auto‑save or use Save if available; verify LittleFS space

10. Open Source & Licensing

Licensing

This project uses a hybrid licensing model.

Hardware

Hardware designs (schematics, PCB layouts, BOMs) are licensed under: CERN-OHL-W v2

Firmware & ESPHome Integration

All firmware, ESPHome configurations, and software components are licensed under: MIT License

This ensures full compatibility with ESPHome and Home Assistant while protecting hardware designs.

See LICENSE files in each directory for full terms.

11. Downloads

12. Support