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.
PROFINET bank in preparation
The full PROFINET bank isn't available yet. Drop your email to get notified at launch and grab an early-bird discount.
Join the waitlist →See the 9 other PROFINET practice questions
Related questions
- PROFINET defines three device roles: IO Controller (equivalent to the PLC master), IO Device (equivalent to a slave: sensor, actuator) and IO Supervisor (engineering PC used for diagnostics and configuration).1. Architecture · Device-Rollen-Modell
- A GSDML file (Generic Station Description Markup Language) is provided by the manufacturer of a PROFINET IO Device and is imported into the engineering tool (e.g. TIA Portal) to integrate the device into the project.1. Architecture · GSDML
- The PROFINET Update Time of an IO Device is configurable individually depending on the application: typical values range from 1 to 128 ms in RT, and down to 250 us in IRT.2. Real-time classes · Update Time
- PROFINET supports several physical topologies: star (via switches), line (daisy-chain through ports integrated in the devices) and ring (with MRP for redundancy), and they may be combined within the same network.3. Topology & cabling · Unterstützte Topologien
- LLDP (Link Layer Discovery Protocol, IEEE 802.1AB) lets PROFINET devices identify each other and automatically discover the network topology, which is exploited by diagnostic tools such as PRONETA or the TIA Portal Topology Editor.4. Diagnostics · LLDP