· Eduardo Vieira · Industrial Automation · 2 min read
Designing Embedded Systems for Industrial Applications
Guidelines I follow when engineering embedded solutions that must survive on factory floors and integrate with OT systems.
Designing Embedded Systems for Industrial Applications
Factory environments punish electronics. Temperature swings, electrical noise, and the demand for 24/7 uptime make industrial embedded design a discipline of its own. Here’s how I approach building embedded devices that thrive on the plant floor.
1. Begin with the Operational Context
- Lifecycle expectations: Many machines run for 15+ years. Document how firmware updates and spare parts will be managed.
- Compliance: Determine which standards apply (UL 508A, IEC 61010, CE, FCC).
- Integration: Identify which PLCs, HMIs, and SCADA systems the device must communicate with.
2. Hardware Design Principles
- Select industrial temperature range components (–40 °C to 85 °C) and derate voltages by at least 20%.
- Provide galvanic isolation on IO facing high-voltage equipment.
- Include transient protection (TVS diodes) and proper grounding to survive noise.
- Plan for field-replaceable modules (e.g., communication daughter cards) to accommodate future protocols.
3. Firmware Architecture
- Use RTOSes like Zephyr or FreeRTOS to separate deterministic control tasks from non-critical services.
- Implement watchdogs, brownout detection, and safe-state routines that operators can trust.
- Provide structured telemetry (MQTT, OPC UA) for monitoring health and performance.
4. Communication Stack
A modern embedded product should speak both OT and IT languages:
| Layer | Protocols |
|---|---|
| Fieldbus | Modbus RTU/TCP, CANopen, EtherCAT |
| Messaging | MQTT (Sparkplug B), AMQP |
| Configuration | REST/GraphQL APIs with role-based access |
5. Security by Design
- Secure boot with signed firmware images.
- Unique credentials per device, preferably managed by a hardware security module.
- Encrypted storage for secrets and certificates.
- Remote attestation to prove device integrity before granting network access.
6. Testing and Validation
- Environmental: Thermal cycling, vibration tests, and ingress protection verification.
- EMC: Conducted and radiated emissions/ immunity testing per IEC 61000.
- Functional: Hardware-in-the-loop simulations using PLC test benches to validate deterministic behavior.
- Field Trials: Deploy pilot units with diagnostic logging enabled to capture real-world edge cases.
7. Maintainability and Support
- Document schematics, BOM, and firmware workflows in a repository accessible to maintenance engineers.
- Provide remote logging and over-the-air update mechanisms that respect change control processes.
- Offer clear troubleshooting guides with LED status indicators and diagnostic ports.
8. Lessons Learned
Projects succeed when controls, IT, and maintenance collaborate from day one. Treat embedded devices as long-term assets that require lifecycle planning. By pairing rugged hardware with secure, well-architected firmware, you can deliver embedded solutions that elevate industrial operations for years to come.