Rice Machine PLC Controller — Industrial Automation System

The Rice Machine PLC Controller is a bespoke industrial automation system built for a rice processing facility. The system replaces a traditional hardware PLC with a software-defined Python controller — significantly reducing hardware costs while adding real-time monitoring, data logging, and a modern web-based HMI.

The core PLC logic is implemented as a Python state machine using the loguru logger and a modular controller architecture. It supports two operating modes: Simulation Mode (for testing and commissioning without physical hardware) and Hardware Mode (connecting to real GPIO/serial drivers for production deployment). The machine state module defines all operating states: Idle, Starting, Running, Stopping, Faulted, and Emergency Stop — with full transition validation and fault handling.

The Human Machine Interface (HMI) is built with Streamlit and runs as a separate browser-based dashboard. Operators get a real-time view of: machine status indicators, conveyor belt speeds, temperature sensors, throughput counters, active faults, and shift production summaries. The HMI communicates with the PLC controller over a local socket connection, ensuring the HMI can crash or restart without affecting the controller.

Logging is handled by loguru with structured log files, automatic rotation, and configurable retention. The test suite covers all state transitions, fault injection scenarios, and simulation-mode outputs. Deployed on a Raspberry Pi 5 at the client site.