What is Wi-Fi?
Wi-Fi is a wireless communication technology based on the IEEE 802.11 standard. It enables devices to connect wirelessly to a network, usually via an Access Point (AP).
In industrial environments, Wi-Fi is used for mobile HMIs, wireless Sensors, maintenance access and temporary network use, but requires strict control because of susceptibility to interference and security risks.
🧠 How does Wi-Fi work?
- Devices (clients) connect to an Access Point (AP) via radio frequencies (2.4 GHz, 5 GHz or 6 GHz)
- The AP is connected to the wired network via a Switch or Router
- Communication takes place according to IEEE 802.11 variants, such as:
- 802.11n/ac/ax (Wi-Fi 4/5/6)
- Wi-Fi supports WPA2/WPA3 security, 802.1X authentication and RADIUS integration
- For industrial reliability, industrial Wi-Fi APs are used with features such as roaming and redundancy
Wi-Fi is suitable for non-mission-critical applications within OT environments.
🏭 Application of Wi-Fi in industrial networks
- Wireless HMI or tablet for operators on the shop floor
- Wireless configuration or monitoring of PLCs and Drives
- Temporary connection during maintenance or calibration
- Integration of mobile barcode/RFID scanners in logistics or production
- Sensor communication in hard-to-reach zones or mobile systems (e.g. AGVs)
Wi-Fi must be segmented and isolated from core OT networks for stability and security.
🔍 Benefits and limitations of Wi-Fi in OT
| Aspect | Benefit | Limitation |
|---|---|---|
| Flexibility | No cabling required | Susceptible to interference from metal, vibration or RF noise |
| Mobility | Free movement of operators or devices | Limited roaming and latency issues |
| Cost | Cheaper than wiring temporary installations | Management overhead with many clients |
| Security | Supports modern standards | Vulnerable when poorly configured or with open networks |
🔐 Security aspects
- Use WPA3-Enterprise with 802.1X and RADIUS authentication
- Segment Wi-Fi via VLAN and Firewall
- Restrict access with MAC address filtering or Port Security on uplinks
- Log all wireless access via SIEM and monitor with network monitoring
- Do not use default SSIDs or passwords – set unique credentials
In OT environments, Wi-Fi is only suitable for controlled, isolated applications.
📌 In summary
Wi-Fi is a convenient wireless technology for mobility and maintenance access, but in industrial networks it must be carefully designed, segmented and secured. Only suitable for applications that do not require continuous real-time availability.