Building an Industrial HMI and Edge Controller on STM32 with FreeRTOS and Modbus TCP
Industrial control demos are often judged by the screen. The more useful question is whether the firmware, HMI and simulated process all explain the same state transition.
SLX FlowControl is a demonstrator built on an STM32H750B-DK. It combines a FreeRTOS control task, an LVGL touch HMI, a Modbus TCP/IP server and a Factory I/O Fill Tank digital twin. The goal is to make behaviour testable before a physical machine is connected.
The problem behind the demo
A buffer tank must accept incoming fluid, supply downstream demand and retain an operating reserve around a target level. That sounds simple until commands overlap, sensors are missing at startup, data stops arriving or an operator needs to understand why the process will not restart.
