01 | Read an Industrial Sensor with ESP32: Modbus RTU from Wiring to Data

Practical Industrial Automation with ESP32 — Lecture 01 Connect an ESP32-S3 to an industrial temperature and humidity sensor, then follow a Modbus RTU reading from the wiring to meaningful engineering units. This opening lecture establishes the sensor, electrical interface, communication settings, request frame, and validation steps used throughout Practical Industrial Automation with ESP32. The reference setup combines an Espressif development board, an isolated Waveshare TTL-to-RS485 converter, and the DFRobot SEN0438 sensor. You will see how the logic and sensor power domains remain separate, why the converter's direction-control method matters, and how the serial profile must match the device. Learn to request two holding registers with function code 03, check the response structure and CRC, and convert the manufacturer's documented example into 47.1% relative humidity and 21.4 °C. The example values are a test vector, not newly measured room conditions. The lesson also introduces the ESP-IDF project, bounded polling, explicit invalid-sample status, an offline frame checker, and a first-power-up procedure. Start with a working USB development environment and review the wiring before applying power. Host checks exercise the example parser; the target build and physical commissioning remain steps to perform on your own hardware. CHAPTERS 00:00 An industrial reading, decoded 00:26 A repeatable bench setup 00:56 ESP32 and converter connections 01:27 The isolated sensor circuit 01:57 The communication profile 02:34 The two-register request 03:07 The reply earns our trust 03:37 From registers to engineering units 04:12 A small, reproducible project 04:44 Poll without inventing data 05:17 A real software check 05:52 Failures stay visible 06:24 First power-up on your bench 06:59 A useful fault-finding order 07:31 Your next reading Presenter: Dr. Redmond R. Shamshiri · University of Southern Denmark Email: ramsha@mmmi.sdu.dk For more information and enquiries, contact Maryam Behjati: maryam@adaptiveagrotech.com #ESP32 #ModbusRTU #IndustrialAutomation