Diagnostics PROFINET: exam questions with worked answers

Questions for the "Diagnostics" topic

1. Q01

   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.

   TrueFalse

   4. Diagnostics· LLDP· Medium

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   Correct answer

   True

   Learning tip

   LLDP is a standard Ethernet protocol natively embedded in PROFINET: each device periodically emits (typically every 5 s) an LLDP frame containing its identity, ports and role; neighbours receive and store this information in the LLDP-MIB; tools such as PRONETA or TIA Portal then query the MIBs and rebuild a visual topology. LLDP also enables the automatic detection of cabling anomalies, for instance a device patched into the wrong port.

   Source: Siemens PRONETA documentation

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2. Q02

   PROFINET distinguishes several alarm types: "Process Alarms" (application events raised by the device), "Diagnostic Alarms" (detected hardware anomalies) and "Maintenance Alarms" (preventive maintenance needs).

   TrueFalse

   4. Diagnostics· Prozessalarme· Medium

   ▸

   Correct answer

   True

   Learning tip

   The PROFINET alarm catalogue is: Process Alarm for application-level events (setpoint exceeded, process cycle complete, application-level safety trigger); Diagnostic Alarm for hardware faults (sensor break, short-circuit, overheating); Maintenance Required / Maintenance Demanded as proactive indicators (operating hours, cycles reached); and Plug / Pull alarms for hot insertion or removal of modules. All of these reach the PLC via the AlarmCR and can trigger dedicated handling routines.

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