Why STM32 for Industrial Control?
STM32 has become the dominant microcontroller platform for industrial board design. The combination of ARM Cortex-M architecture, extensive peripheral integration, long product lifecycle (10+ years), and competitive pricing makes it the go-to choice for PLC replacement applications. ST Microelectronics' broad portfolio allows engineers to scale from simple sensor gateways to complex multi-axis motion controllers within the same development ecosystem.
Series Comparison: F103 vs F407 vs F429 vs H743
| Specification | STM32F103ZE | STM32F407 | STM32F429 | STM32H743 |
|---|---|---|---|---|
| Core | Cortex-M3 | Cortex-M4F | Cortex-M4F | Cortex-M7 |
| Clock Speed | 72 MHz | 168 MHz | 180 MHz | 480 MHz |
| Flash / RAM | 512KB / 64KB | 1MB / 192KB | 2MB / 256KB | 2MB / 1MB |
| FPU | No | Yes (single) | Yes (single) | Yes (double) |
| CAN | 1× CAN 2.0B | 2× CAN 2.0B | 2× CAN 2.0B | 2× FDCAN |
| Ethernet | No | Yes (10/100) | Yes (10/100) | Yes (10/100) |
| ADC Resolution | 12-bit (2×) | 12-bit (3×) | 12-bit (3×) | 16-bit (3×) |
| Price Tier | $ (Lowest) | $$ (Mid) | $$$ (Mid-High) | $$$$ (High) |
| Best For | Gateway, HMI, basic I/O | General PLC replacement | EtherCAT, display | Vision, DSP, precision |
STM32F103ZE — The Entry-Level Workhorse
The F103 series is the most cost-effective option for applications that don't require floating-point computation or Ethernet connectivity. It's ideal for:
- HMI interfaces: Touch screen controllers with UART/RS485 communication
- Sensor gateways: Data collection from analog sensors, conversion and forwarding via Modbus RTU
- Simple I/O control: Relay control, valve switching, basic sequencing
- DTU (Data Transfer Unit): Protocol conversion between CAN, RS485, and Ethernet
STM32F407 — The PLC Replacement Sweet Spot
The F407 offers the best balance of performance and cost for mainstream PLC replacement. Its Cortex-M4 with FPU enables real-time control algorithms (PID, feedforward, filtering) that were previously only practical on expensive PLC CPUs.
- Machine controllers: Packaging, labeling, cutting, and assembly machines
- Multi-protocol gateways: Dual CAN + Ethernet + RS485 protocol bridging
- Motor control: FOC (Field-Oriented Control) for BLDC and PMSM drives
- Data acquisition: High-speed ADC sampling with DMA and real-time processing
STM32F429 — EtherCAT and Display Applications
The F429 extends the F4 family with an LCD controller (LTDC) and more RAM, making it the ideal platform for EtherCAT slave implementations with integrated HMI. At IdeatorTech, our EtherCAT board pairs the F429 with a dedicated EtherCAT slave controller for deterministic real-time communication.
- EtherCAT slave nodes: Distributed I/O, servo drives, sensor modules
- Embedded HMI: Controllers with built-in display for operator interaction
- Multi-axis coordination: Synchronized motion control via EtherCAT distributed clocks
STM32H743 — Maximum Performance
The H7 series delivers desktop-class computing power (480 MHz, double-precision FPU, hardware JPEG decoder) in an industrial MCU package. Choose H7 when your application demands:
- Machine vision: Real-time image processing, defect detection, barcode/QR reading
- Precision measurement: 16-bit ADC with oversampling for high-accuracy sensor applications
- Complex DSP: Advanced signal processing, vibration analysis, predictive maintenance
- Edge computing: On-board AI inference for anomaly detection and process optimization
Decision Framework
Use this quick decision tree to select the right platform:
- Budget is the primary concern and application is basic I/O → STM32F103ZE
- General machine control with CAN/RS485/Ethernet → STM32F407
- EtherCAT real-time networking or need integrated display → STM32F429
- High-performance computing (vision, DSP, AI inference) → STM32H743
For a cost comparison across all platforms, see our PLC Replacement Cost Estimation Calculator.