A PROFINET IO Device can spontaneously raise a "Diagnostic Alarm" to its Controller in the event of an anomaly (sensor cable break, overheating, short-circuit), without waiting for a read request.
True
A Diagnostic Alarm is an asynchronous telegram emitted by the Device towards the Controller, with no polling required. It is encoded according to the ChannelErrorType (line break, short-circuit, incorrect configuration, etc.), and the Controller (visible to the programmer in TIA Portal) receives the alarm in its diagnostic buffer and can trigger a handling routine. This event-driven mechanism is one of the major advantages compared with polling-based Modbus.
Always programme an OB diagnostic interrupt to react to Diagnostic Alarms; relying purely on cyclic IO values means you will only notice a broken sensor when the process drifts, not the moment it fails.
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
- Which PROFINET real-time class delivers the strictest determinism (cycle <= 31.25 us with jitter <= 1 us), making it suitable for motion-control applications?2. Real-time classes · RT vs. IRT vs. NRT
- A PROFINET network running in IRT mode requires industrial Ethernet switches that are specifically IRT-certified and implement precise time-based scheduling (typically prioritised cut-through forwarding).2. Real-time classes · IRT-Switches
- The MRP (Media Redundancy Protocol) handles redundancy on a PROFINET ring using one "MRP Manager" node and several "MRP Clients", guaranteeing a failover time below 200 ms in the event of a cable break.3. Topology & cabling · MRP (Media Redundancy)
- PROFINET "S2 redundancy" denotes an architecture in which two IO Controllers (one primary, one standby) are connected to the same IO Device, with automatic failover in case of primary failure and without loss of communication.3. Redundancy · S2-Redundanz
- Which PROFINET Conformance Class includes support for IRT (Isochronous Real-Time)?5. Conformance Classes · CC-A / CC-B / CC-C