ESP32-S3 8-Channel Industrial Relay Module with RS485 and Ethernet

The ESP32-S3-ETH-8DI-8RO is an industrial-grade relay module based on the ESP32-S3 microcontroller with Xtensa 32-bit LX7 dual-core processor and up to 240 MHz clock frequency. The wireless section supports 2.4 GHz WiFi (802.11 b/g/n) as well as Bluetooth 5 LE, allowing wireless control via local networks or mobile devices. The module features eight high-quality relays with a contact rating of up to 10 A at 250 V AC or 30 V DC in 1NO/1NC configuration. Additionally, there are eight digital inputs with 5 to 36 V input voltage available, which can accept both passive (dry contacts) and active signals (NPN or PNP) via bidirectional optocoupler isolation. For wired networking, a 10/100 Mbps Ethernet interface with W5500 chip is available, complemented by a galvanically isolated RS485 interface for Modbus communication. An additional 120 ohm termination resistor can be activated via jumper. The power supply can be provided via USB Type-C (5 V) or the terminal block with a wide input voltage range of 7 to 36 V DC. Onboard, there is also an RTC with PCF85063ATL and battery holder (1220) for scheduled tasks, a TF card slot for external storage, a buzzer, an addressable WS2812 RGB LED on GPIO38, as well as status LEDs for power supply and RS485 TX/RX. Multiple isolation levels (optocouplers, digital isolation, power supply isolation) and TVS components protect the controller from interference and voltage surges from the connected peripherals. The module is delivered in a robust ABS DIN rail housing (35 mm) and can thus be easily mounted in industrial control cabinets. The antenna is connected via an external SMA connector and is included as a 4 dB rod antenna. Programming is done directly via USB Type-C in the Arduino IDE, MicroPython, or ESP-IDF.

Recommended Accessories:

DIN rail power supply 24 V DC for safe and stable supply in the control cabinet
USB-C cable for initial setup and firmware updates
Modbus RTU sensors (temperature, humidity, current) for expansion via the RS485 interface
CR1220 coin cell battery to buffer the real-time clock during power failure
Industrial Cat6 patch cables for reliable LAN connection

Features:

ESP32-S3 microcontroller with Xtensa 32-bit LX7 dual-core processor, 240 MHz, 16 MB flash, and 8 MB PSRAM
Eight relay outputs with contact rating up to 10 A 250 V AC or 10 A 30 V DC in 1NO/1NC configuration
Eight digital inputs with 5 to 36 V voltage range, passive or active (NPN/PNP) with bidirectional optocoupler isolation
Interfaces include WiFi 2.4 GHz, Bluetooth 5 LE, isolated RS485 interface, 10/100 Mbps Ethernet via W5500 and USB Type-C
Industrial power supply via terminal block with 7 to 36 V DC wide range input or alternatively 5 V via USB Type-C
DIN rail mounting in ABS housing with integrated RTC, TF card slot, buzzer, and WS2812 RGB LED

Application Examples:

Control of machines and 230 V consumers in building automation and home automation
Connection of Modbus sensors and PLC extensions via RS485 in industrial plants
Building an IoT gateway with MQTT connection to cloud services or Home Assistant
Control center for lighting, ventilation, and heating in smart home installations on DIN rail
Recording digital status signals from limit switches and buttons with simultaneous actuator control

Documentation:

Technical Specifications:

Manufacturer: Waveshare
Manufacturer SKU: ESP32-S3-ETH-8DI-8RO
Microcontroller: ESP32-S3-WROOM-1U-N16R8, Xtensa 32-bit LX7 dual-core, 240 MHz, 16 MB flash, 8 MB PSRAM
Wireless communication: 2.4 GHz WiFi (802.11 b/g/n), Bluetooth 5 LE
Ethernet controller: W5500, 10/100 Mbps
Relay outputs: 8 channels, ≤10 A 250 V AC or ≤10 A 30 V DC, 1NO 1NC
Digital inputs: 8 channels, 5 to 36 V, passive or active (NPN/PNP), bidirectional optocoupler isolation
RS485 interface: isolated, with switchable 120 ohm termination resistor, TVS protection
Other ICs: TCA9554PWR (IO expander), PCF85063ATL (RTC), MP1605GTF-Z (DC-DC)
RGB LED: WS2812, controllable via GPIO38
Status LEDs: PWR (red), RS485 TX (green), RS485 RX (blue)
Buzzer: integrated, controlled via GPIO46
Storage: TF card slot for external storage expansion
RTC battery: holder for 1220 coin cell (3 V to 3.3 V, rechargeable only)
Antenna connector: SMA female, external antenna included
USB connection: USB Type-C for power supply, firmware upload, and debug
Power supply: 7 to 36 V DC via terminal block or 5 V/1 A via USB Type-C
Housing: ABS DIN rail housing for 35 mm DIN rail
Development environment: Arduino IDE, MicroPython, ESP-IDF
Product dimensions: 175 × 90 × 40 mm
Package dimensions: 187 × 130 × 46 mm
Gross weight: 390 g