LoRa-Enabled Smart RS485 Data Logger and MQTT Gateway for Industrial IoT Applications Using ESP32

Industry 4.0 has driven the need for efficient data gathering and analysis to enhance business performance. However, collecting data from assets in challenging environments with uncertain network conditions remains a major obstacle. In this paper, we propose the Smart Data Logger, a gateway designed to reliably collect data from various sensors and devices and transmit it to the cloud or a server. We address the challenge of converting data from different devices and protocols to enable Industrial Internet of Things (IIoT) readiness. Our gateway utilizes an ESP32 microcontroller with a Wi-Fi board and an RS485 to TTL add-on module for communication. It supports bidirectional communication between field devices and cloud applications and provides a Modbus RTU interface on RS485 for onsite device connectivity. The gateway incorporates a GSM A7670 4G LTE module for internet connectivity and includes a built-in SD card for data storage during connectivity loss. Furthermore, an onboard LoRa E32 868MHz module allows multiple nodes to connect and send data to the centralized gateway. The data logger gateway features a two-column data storage pattern with timestamps and data packets, ensuring accurate data recording. A realtime clock (RTC) DS3231 with SPI communication is used for timestamping. Data stored on the SD card is transmitted to the cloud via MQTT when connectivity is restored. Our gateway architecture includes a smart agent for data conversion and supports configuration through embedded web pages. It provides an easy and secure solution for IIoT applications, allowing integration with existing operational technology. Overall, our Smart Data Logger gateway enables robust data collection and analysis in challenging industrial environments.