What an edge gateway does
- A gateway translates and secures. It speaks Modbus, CAN, BLE or LoRa on the field side and MQTT or HTTPS to the cloud, so legacy machines can be connected without replacing them.
- Local buffering is essential. Factory and rural links drop; a gateway that stores data and forwards it later prevents gaps.
- Off-the-shelf gateways suit pilots; custom designs suit volume, special I/O, tight cost or particular certifications.
- Security is a design requirement: unique credentials, TLS, signed updates and no open management ports.
Typical gateway architecture
| Layer | Examples |
|---|---|
| Field interfaces | RS-485 Modbus RTU, Modbus TCP, CAN, 4-20 mA, digital I/O, BLE, LoRa concentrator |
| Processing | Cortex-M for simple bridging; Cortex-A with Linux for edge logic and containers |
| Backhaul | Ethernet, Wi-Fi, LTE with failover |
| Cloud protocols | MQTT over TLS, HTTPS, OPC UA |
| Management | Remote configuration, logging, signed OTA updates |
Build or buy
Buy when a catalogue gateway covers your interfaces, certifications and volume. Build when you need a specific mix of I/O, a lower unit cost at volume, a particular form factor or DIN-rail enclosure, or ownership of the software roadmap. We help make that decision honestly, and can start on a commercial gateway and design a custom one only if the pilot justifies it.
Reliability features we include
- Store-and-forward queue on non-volatile storage with a defined retention policy.
- Hardware watchdog and a supervised application process.
- Wide-range power input with surge and reverse-polarity protection for factory use.
- Network failover between Ethernet and cellular.
- Time synchronisation so data from different sites can be compared.
Industrial context
Gateways are the core of retrofit projects: reading Modbus registers from drives and meters, adding vibration or temperature sensors, and publishing to an MQTT broker. Our write-up on IoT in Indian manufacturing shows the architecture, and the industrial IoT page describes the engagement.
Sources and further reading
- Modbus Organization — Modbus protocol specifications.
- OPC Foundation — OPC UA specifications for industrial interoperability.
- ISA/IEC 62443 series — Industrial automation and control systems security standards.
Last reviewed: October 2026. Regulations and product availability change; confirm current rules with the issuing authority before you commit to a design.