medium PROFINET exam questions
Certified PROFINET Engineer mock exam questions selected at medium level. Ideal for consolidating what you've learned and gauging your real level.
Medium level questions
Q01
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.TrueFalse1. Architecture· GSDML· MediumCorrect answerTrueLearning tipGSDML is the PROFINET equivalent of the ".knxprod" file in KNX. It is a standardised XML format that describes the supported modules, submodules, parameters and diagnostic information of the device. It is imported once into a project or into the local library of the engineering station, and the rule of thumb is to always use the most recent GSDML version that is compatible with the device firmware.
Q02
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.TrueFalse2. Real-time classes· Update Time· MediumCorrect answerTrueLearning tipThe Update Time is the refresh period for cyclic IO data exchanged between the Controller and a Device. The shorter the Update Time, the higher the network load: a slow sensor (e.g. temperature) is fine with 128 ms, a proximity sensor or actuator typically runs at 4-8 ms, and a motion drive is usually configured at 1 ms or below in IRT. Good practice is to size each device's Update Time to actual need in order to avoid network saturation and preserve overall determinism.
Q03
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.TrueFalse4. Diagnostics· LLDP· MediumCorrect answerTrueLearning tipLLDP 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 documentationQ04
PROFINET distinguishes several alarm types: "Process Alarms" (application events raised by the device), "Diagnostic Alarms" (detected hardware anomalies) and "Maintenance Alarms" (preventive maintenance needs).TrueFalse4. Diagnostics· Prozessalarme· MediumCorrect answerTrueLearning tipThe 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.
Q05
In TIA Portal, the expected topology can be downloaded into the PROFINET PLC; at start-up the PLC compares the actual topology (discovered via LLDP) against the expected one and raises an alarm if they differ, which makes cabling errors automatically detectable.TrueFalse16. Configuration· Topologie-Download· MediumCorrect answerTrueLearning tipTopology Download acts as a re-cabling safety net: the Configured Topology captures what the integrator drew (port X of device A connects to port Y of device B), the Actual Topology is what LLDP discovers at runtime, and any mismatch raises a PLC alarm. This avoids the classic failure mode where maintenance reconnects a cable to the wrong port, the plant keeps running, and the error is only discovered weeks later when the next device replacement silently fails. It is now standard practice in modern industrial and tertiary deployments.