ESC3B04 DIN rail-compatible industrial relay board features 4 outputs, 4 analog/digital inputs, RS-485 interface
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The ESC3B04 is a compact DIN rail-compatible relay board built around the ESP32-C3 Super Mini module for building Wi-Fi remote switches, voltage monitoring systems, motor control, timed automation, and RS-485-based setups.
The board features four 10A relay outputs, four 0–5V/10V analog voltage inputs (also configurable as 12–24V PNP digital inputs), an RS-485 interface, and a push-button input. It operates on a 7–25V DC supply and supports direct installation in control panels or DIN-rail enclosures.
ESC3B04 relay board specifications:
- Wireless module –16-pin ESP32-C3 Super Mini module
- SoC – Espressif Systems ESP32-C3FH4, single-core 32-bit RISC-V microcontroller @ up to 160 MHz; 400 KB SRAM; 4MB flash
- USB – 1x USB Type-C port for programming
- Ceramic antenna
- I/Os and expansion
- 4x relays (10A/240VAC)
- 4x 0-5V/0-10V analog voltage inputs (can be used as 12-24V digital inputs)
- Serial – RS-485 interface for Modbus or custom protocol communication
- Misc
- User button
- Power LED
- Power Supply
- 7-25V DC wide range supply voltage via terminal block
- Current consumption
- Standby – 15mA
- 1 relay ON – 74mA
- 2 relays ON – 106mA
- 3 relays ON – 131mA
- 4 relays ON – 164mA
- Dimensions – 77 x 72 x 19 mm (board only)
- Weight – 80 grams (board only), 144 grams with DIN enclosure


The company mentions that the ESP32-C3 board can be programmed with the Arduino IDE, ESP-IDF framework, or PlatformIO. No code is provided, so the users have to program RS-485, Wi-Fi control, and automation logic by themselves.
Previously, we have written about other Espressif-based relay boards like the XIAO 6-Channel Wi-Fi 5V DC Relay Board, the ESP32 IoT Relay Board” credit card-sized quad relay board compatible with Tasmota, and the Olimex ESP32-C6-EVB, out of which the Olimex board is most feature-rich and integrates Wi-Fi 6, BLE 5.0, and Zigbee/Thread via the ESP32-C6, and includes 4 opto-isolated digital inputs, 4 relays, USB-C for programming, and more.
The ESC3B04 industrial relay board is available with the ESP32-C3 Super Mini module on AliExpress for $12.27 or $12.84 with the DIN rail mount. More information about the product can be found on Eletechsup’s product page.
