medium KNX Basic exam questions

Medium level questions

1. Q01

   Within a KNX area, the maximum number of Line Couplers is 15, one per subsidiary line.

   TrueFalse

   2. TP Topology· Bereichsbegrenzungen· Medium

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   Correct answer

   True

   Learning tip

   True. A KNX area is built around one main line that connects up to 15 subsidiary lines, each attached to the main line through its own Line Coupler. The limit of 15 follows directly from the topology addressing scheme, which reserves 4 bits for the line identifier within an area. Each subsidiary line itself can then host up to 64 devices (or 256 with additional line segments and segment repeaters).

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2. Q02

   The 'Reset Device' command in ETS performs a software restart of a KNX device without erasing its individual address or its application configuration.

   TrueFalse

   7. ETS Programming· Geräte-Reset· Medium

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   Correct answer

   True

   Learning tip

   Reset Device = warm restart: the device loses its runtime state (RAM), reinitialises its timers, Cyclic Send and counters, but preserves its individual address, application program, ETS parameters, and Group Address to Group Object bindings. It is useful to force the re-emission of initial values (cyclic send after a crash), to test a specific power-up behaviour, or to unstick a device frozen in an inconsistent state without having to reload the configuration. Not to be confused with Unload All (full decommissioning) or with simply switching off mains power.

   Source: ETS6 User Manual — Device commands

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3. Q03

   A single Group Object can be associated simultaneously with several Group Addresses in ETS, which is typically used so that an actuator reacts to several commands (e.g. individual command + zone command + scene).

   TrueFalse

   7. ETS Programming· Multi-Binding· Medium

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   Correct answer

   True

   Learning tip

   Multi-binding is a fundamental KNX pattern. Concrete examples: a lighting circuit that reacts to its local switch, to an 'all off' corridor command and to a 'leave for work' scene; a roller shutter that reacts to its local button, to a zone master and to a safety scenario (automatic close on storm warning). The actuator has a single Switch Control Group Object bound to 3-4 different Group Addresses (Lighting_Local_LivingRoom, Lighting_All_Off, Scene_Departure). All these addresses can write into the Group Object; only one (the sending address) is used when emitting status.

   Source: Porto KNX — KNX Basic Course, Multi-binding

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4. Q04

   A standard KNX device that is fully programmed contains an Individual Address, an application, parameters and the Group Addresses.

   TrueFalse

   1. System Overview· Offizielle Musterprüfung 3· Medium

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   Correct answer

   True

   Learning tip

   True. After a successful complete download from ETS, a standard KNX device stores four things: its Individual Address (unique identifier on the topology), its application program (the firmware-level logic for its function), its parameter values (the configuration choices made in ETS), and the list of Group Addresses linked to its Group Objects (the communication side). Only with all four does the device participate correctly in the installation.

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5. Q05

   The programming button on a KNX product or the BCU has to be pressed to allocate the Group Addresses during the commissioning stage.

   TrueFalse

   7. ETS Programming· Offizielle Musterprüfung 4· Medium

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   Correct answer

   False

   Learning tip

   False. The programming button puts the device into 'programming mode' so that ETS can write its Individual Address (Physical Address), not its Group Addresses. Once the Individual Address has been downloaded, the application program and the Group Address links are downloaded over the bus using that Individual Address as the destination, with no further button press required. Confusing the two downloads is one of the most common Basic-exam pitfalls.

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6. Q06

   The correct operation of a sensor in a KNX installation can be verified by comparing the filter tables.

   TrueFalse

   6. ETS Project Design· Offizielle Musterprüfung 4· Medium

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   Correct answer

   False

   Learning tip

   False. Filter tables live in line and area couplers and describe which Group Addresses are allowed to cross the coupler; they say nothing about whether a given sensor actually sends a telegram when stimulated. To verify that a sensor works, the correct tools are the ETS Group Monitor or Bus Monitor, which show in real time the telegrams generated by the sensor and the values carried. Filter-table comparison is a topology/routing check, not a functional sensor check.

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