PROFINET over WLAN (IEEE 802.11) is feasible for mobile applications (AGVs - Automated Guided Vehicles, mobile robots, overhead cranes) but is limited to RT (not IRT) because of the inherent jitter of Wi-Fi.
True
PROFINET on WLAN relies on industrial Wi-Fi products such as Siemens SCALANCE W, Phoenix Contact FL WLAN or Hirschmann access points, with optimised roaming (under 50 ms handover between APs, compared with 200+ ms on consumer Wi-Fi). Typical Update Times sit in the 32-128 ms range (versus under 8 ms on wired Ethernet), and IRT is impossible because Wi-Fi jitter exceeds 100 us. Encryption requires at least WPA2/3 Enterprise. Typical use cases are automated shuttles, mobile robotics and temporary maintenance access, but the technology is critically unsuitable for safety functions or motion control.
Treat WLAN as a 'soft real-time' link only: any control loop whose failure has a safety consequence must run on a wired ring or PROFIsafe, never on a roaming Wi-Fi connection.
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