ESP32 Device Modbus Monitoring and Control

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FastBee IoT Terminal

Core Specifications

Parameter	Description
Chip	ESP32-WROOM-32U
CPU	Dual-core Xtensa LX6 @ 240 MHz
Flash	4 MB SPI Flash
SRAM	520 KB
Wireless	WiFi 802.11 b/g/n + Bluetooth 4.2 + BLE
Supply Voltage	DC 9-36V
Features	External antenna, USB flash port, configuration button

Terminal Block Description

Terminal	Function	Pin
A/L	RS485-A (TX)	GPIO17
B/H	RS485-B (RX)	GPIO16
VCC	Power positive	DC 9-36V
GND	Power negative	—
DGND	Digital ground (isolated GND)	—
EGND	Protective ground (connects to device enclosure)	—
IO/L	Isolated digital I/O low-side	GPIO21
IO/H	Isolated digital I/O high-side	GPIO22

LEDs and Buttons

Name	Type	Description
POWER	LED	Power indicator, steady on means power is normal
STATE	LED (GPIO5)	Status indicator, lights up on low level
DATA	LED	Communication indicator, blinks during data TX/RX
BOOT	Button (GPIO0)	Long press to enter configuration mode

Recommended PlatformIO Environment

Select the environment matching the board's chip, Flash and PSRAM. MQTT, Modbus RTU and GPIO isolated I/O also require their runtime features and valid wiring.

After flashing, you can confirm the terminal online status, IP, WiFi, memory usage and uptime via the Web console.

powershell -ExecutionPolicy Bypass -File scripts\deploy.ps1 -Env esp32 -Port COM6

Typical Application Scenarios

• Industrial Acquisition Gateway: Connect Modbus RTU slave devices via RS485, acquire temperature/humidity, meter data and report to the platform
• Remote Control Terminal: Isolated IO terminals control relays, solenoid valves and other actuators
• Field Monitoring Node: Wide voltage supply (9-36V) suitable for outdoor or industrial site deployment

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More Hardware

Welcome to submit your hardware adaptation cases. When submitting a PR, please include:

1. Hardware photos
2. Core specification table
3. Pin mapping description
4. Recommended PlatformIO environment and configuration