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KNX Basic
Sourced bankKNX Association
KNX Basic
Sourced bankKNX Association
By topic
System Overview
4- 01The KNX standard is internationally standardised under the reference ISO/IEC 14543-3.EasyV/F→
- 02The four communication media supported by KNX are TP, IP, RF and PL.EasyV/F→
- 03The Individual Address of a KNX device is used to switch electrical loads on and off.MediumV/F→
- 04A standard KNX device that is fully programmed contains an Individual Address, an application, parameters and the Group Addresses.MediumV/F→
Exam Meta
3- 01The KNX Basic theoretical exam is open-book: candidates may consult their PDF or paper course documentation during the test.EasyV/F→
- 02The asymmetric scoring of the KNX Basic exam (+1 for a correct answer, -0.5 for a wrong one, 0 for an abstention) makes it sensible to abstain on questions whose answer is completely unknown rather than to guess at random.MediumV/F→
- 03During the ETS practical exam, the candidate may be asked to diagnose a pre-configured installation set up by the trainer (fault finding), not only to program a new installation from scratch.HardV/F→
TP Topology
9- 01What is the maximum number of lines that a KNX TP area may contain?MediumQCM→
- 02A KNX TP line can accommodate up to 256 devices when line repeaters are used.MediumV/F→
- 03On how many bits is the Group Address encoded inside a KNX TP1 telegram?HardQCM→
- 04A KNX TP installation can accommodate at most 14 400 devices without using repeaters.HardV/F→
- 05The Group Address space in KNX TP1 allows up to 65 536 different Group Addresses (2^16).HardV/F→
- 06A KNX TP1 line may be divided into a maximum of 4 physical segments, each of 64 devices, giving 256 devices per logical line.HardV/F→
- 07Within a KNX area, the maximum number of Line Couplers is 15, one per subsidiary line.MediumV/F→
- 08The Individual Address is structured in the following way: Backbone coupler. Line coupler. Bus coupling unit.MediumV/F→
- 09In an installation predating 2018, a maximum of 64 sensors, actuators, line couplers and backbone couplers can be connected to a TP main line.HardV/F→
Bus Devices
5- 01Among the following Group Object flags, which one must be enabled so that the device transmits a telegram whenever the object's value changes?MediumQCM→
- 02DPT 1.001 (Switch) and DPT 1.008 (UpDown) have the same bit length and the same binary structure; only their semantic meaning differs.MediumV/F→
- 03On a KNX device, the configuration parametrised by ETS is stored in non-volatile memory (EEPROM or Flash), whereas the runtime states (current values of the Group Objects) live in volatile RAM.MediumV/F→
- 04You always need two Group Addresses in order to link a sensor with an actuator.MediumV/F→
- 05The destination address in a telegram can be either a Group Address or an Individual Address.MediumV/F→
KNX RF
3- 01What is the main carrier frequency used by KNX RF in Europe?EasyQCM→
- 02KNX RF Multi is newer than KNX RF Ready and uses several frequency channels to improve the robustness of the communication.MediumV/F→
- 03An RF Coupler (Media Coupler) acts as a gateway between a KNX RF segment and a KNX TP segment, allowing RF devices to take part in the same logical installation as TP devices.MediumV/F→
TP Installation
3- 01What is the electrical classification of the KNX TP bus power supply?EasyQCM→
- 02A bus termination (end-of-line resistor) must be installed at each end of a KNX TP segment, in the same way as for an RS-485 bus.MediumV/F→
- 03The permitted length of the bus cable within a line segment is between 1 000 m and 2 000 m, depending on the data-transmission rate.MediumV/F→
ETS Project Design
3- 01Which notation is used in ETS for a Group Address in the 3-level structure?EasyQCM→
- 02ETS Lite is limited to 20 devices per project, whereas ETS Professional has no such limit.MediumV/F→
- 03The correct operation of a sensor in a KNX installation can be verified by comparing the filter tables.MediumV/F→
ETS Programming
5- 01The physical programming button on a device must be pressed before every parameter download.MediumV/F→
- 02After a minor parameter change in ETS, which type of download is typically used to minimise the time spent on the bus?MediumQCM→
- 03The 'Reset Device' command in ETS performs a software restart of a KNX device without erasing its individual address or its application configuration.MediumV/F→
- 04A 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).MediumV/F→
- 05The programming button on a KNX product or the BCU has to be pressed to allocate the Group Addresses during the commissioning stage.MediumV/F→
Diagnostics
2KNX Secure
3- 01KNX Data Secure encrypts telegrams at the application layer (Group Object), whereas KNX IP Secure encrypts at the transport layer (between IP Routers).MediumV/F→
- 02The FDSK (Factory Default Setup Key) of a Secure device is a factory key, printed on the device as a QR code, that is used when the device is first integrated into ETS.HardV/F→
- 03Activating Data Secure on a Group Address adds a per-telegram overhead (authentication and encryption) that reduces the usable application payload.HardV/F→
KNX Advanced
Sourced bankKNX Association
KNX Advanced
Sourced bankKNX Association
By topic
Couplers
2- 01In KNXnet/IP Routing, several IP Routers on the same VLAN share traffic via multicast 224.0.23.12, forming an IP backbone with no master-slave hierarchy between the routers.HardV/F→
- 02Increasing the number of tunnelling connections on a KNX IP interface raises the count of additional individual addresses required.MediumV/F→
Smart Metering
5- 01To transmit cumulative active energy consumption in kWh from a KNX meter, DPT 13.013 (Active Energy in kWh, signed 32-bit) is more appropriate than DPT 14.056 (Power), which encodes an instantaneous power in W.MediumV/F→
- 02A battery energy storage system (BESS, e.g. Tesla Powerwall, Sonnen, BYD) integrated into KNX typically exposes its state of charge (SoC) through DPT 5.001 (0-100 %) and its instantaneous power (charge or discharge) through DPT 14.056 (signed W).HardV/F→
- 03KNX energy meters typically transmit cumulative energy in DPT 13.010 (4-byte signed counter, Wh).MediumV/F→
- 04KNX active power values are typically transmitted in watts using DPT 14.056.MediumV/F→
- 05Energy management in KNX can include load shedding in order to prevent grid overload during peak demand.MediumV/F→
Project best practices
2- 01A standard KNX end-of-works deliverable typically includes the .knxproj project file, printed documentation (topology, Group Address table, electrical schematics), functional-test reports, user training, and a separate .knxkeys keyring file when KNX Secure is used.MediumV/F→
- 02A typical 3-5 year KNX maintenance contract usually includes: an annual preventive visit (PSU check, bus load, vendor firmware updates), curative intervention within 4-24 h depending on SLA, an automatic monthly backup of the ETS project, and an annual parameter review with the client.MediumV/F→
Power supplies
1HVAC Control
3- 01DPT 20.102 (HVAC Mode) encodes the four standard modes - Comfort (1), Standby (2), Economy (3) and Building Protection (4) - and is applied as a cascade from the currently active mode.MediumV/F→
- 02To control a 4-pipe fan-coil unit over KNX, three Group Objects are typically used: a fan speed (DPT 5.010 or DPT 5.001), a cooling signal and a heating signal (both DPT 5.001 for the valves).HardV/F→
- 03Window contacts in a room can switch the HVAC system to frost protection mode through a KNX logic link.MediumV/F→
Lighting Control
10- 01A KNX/DALI gateway allows up to 64 DALI ballasts on a single DALI bus to be driven from KNX commands, with addressing either individual or by DALI group.MediumV/F→
- 02What is the principle of Constant Light Control regulation in KNX?HardQCM→
- 03Tunable White control (variable colour temperature, e.g. 2700 K warm to 6500 K cool) over KNX typically uses two distinct DPTs: one for the overall intensity (DPT 5.001, %) and one for the colour temperature (DPT 7.600, K).MediumV/F→
- 04A KNX presence detector configured with a 15-minute timeout keeps the lighting on for that duration after the last detection, then automatically switches it off.MediumV/F→
- 05The emergency lighting of a building CANNOT be driven by KNX alone: it must comply with dedicated standards (NF EN 1838, EN 50172) that require a self-contained system with a backup battery.HardV/F→
- 06Although emergency lighting must remain an autonomous system certified to EN 50172, KNX can be used to automate the monthly functional tests and the annual duration tests required by the standard, via a dedicated DALI-2 gateway to the emergency luminaires.HardV/F→
- 07Human Centric Lighting (HCL), also called circadian lighting, in KNX automatically modulates the colour temperature (Tunable White, DPT 7.600 K) over the day: cool (5500-6500 K) in the morning to stimulate, neutral (4000-5000 K) at midday, and warm (2700-3000 K) in the evening to support sleep.HardV/F→
- 08DALI devices can be commissioned through the KNX/DALI gateway, typically using ETS apps or manufacturer-specific tools.MediumV/F→
- 09RGB control via KNX is typically performed with 3-byte colour telegrams (DPT 232.600).MediumV/F→
- 10An RGB strip driven by a KNX dimmer can alternatively be controlled through separate 1-byte channels, one per colour.MediumV/F→
KNX Secure
2- 01On highly sensitive KNX Secure installations (strategic sites, defence buildings), the keyring keys can be stored in a Hardware Security Module (HSM) attached to ETS, guaranteeing that the keys never leave the secure hardware even during download operations.HardV/F→
- 02KNX IP Secure encrypts the entire IP communication between IP devices.MediumV/F→
BACnet
Sourced bankASHRAE / BACnet International
BACnet
Sourced bankASHRAE / BACnet International
By topic
Architecture
2- 01BACnet relies on an object-oriented model: every device exposes Objects (e.g. Analog Input, Binary Output) that contain Properties (Present_Value, Object_Name, Description, etc.).EasyV/F→
- 02Which of the following BACnet object types is typically used to represent a user-adjustable temperature setpoint (an analogue value that the BMS can write) ?MediumQCM→
Object types
3- 01The BACnet Multistate Value (MSV), Multistate Input (MSI) and Multistate Output (MSO) objects encode enumerations with several states (3 or more discrete values), such as HVAC modes (Comfort/Standby/Eco) or system states (Auto/Manual/Off).MediumV/F→
- 02The BACnet Calendar object stores a list of exceptional dates (public holidays, vacations, exceptional closures) that can be referenced by several Schedule objects to apply differentiated behaviour on those days.MediumV/F→
- 03The BACnet Notification Class object defines who must receive alarm notifications (Recipient_List), with what priority, and whether acknowledgement is required.HardV/F→
Services
2- 01ReadProperty and WriteProperty are the most widely used BACnet services: they let a client (typically the BMS) read or write the value of a Property of a remote Object.EasyV/F→
- 02The SubscribeCOV service lets a client subscribe to value changes of a Property of a remote Object: the device then automatically emits a ConfirmedCOVNotification or UnconfirmedCOVNotification on each change, avoiding the need to poll.HardV/F→
Practical
2- 01When an MS/TP segment is not working, the classic checks are: 120 ohm terminations at both ends, bias resistors (typically 680 ohm) installed on one device, a unique MAC per device, the same baud rate on every device, and correct cable polarity.HardV/F→
- 02The standard cable for BACnet MS/TP is an AWG 18-22 shielded twisted-pair with a 120 ohm characteristic impedance and capacitance below 30 pF/ft (98 pF/m), covering distances up to 1200 m at 9600 baud.MediumV/F→
Trending & Scheduling
1Modbus
Sourced bankModbus Organization
Modbus
Sourced bankModbus Organization
By topic
Practical
2- 01Programming a Modbus master inside a PLC (Siemens TIA, Wago CoDeSys, Schneider Unity Pro) is done through standardised Function Blocks (e.g. MB_CLIENT, MODBUS_CLIENT) that encapsulate requests (Read Holding, Write Single Register, etc.) with automatic handling of retries and timeouts.MediumV/F→
- 02When integrating a new Modbus slave with an unknown byte order, systematically testing the four combinations (ABCD, DCBA, BADC, CDAB) against a known float value is faster than relying on the incomplete or incorrect vendor documentation.HardV/F→
Function codes
5- 01Which Modbus function code is used to READ the Holding Registers (16-bit read/write registers) of a slave?MediumQCM→
- 02When a Modbus slave cannot execute a request (invalid address, out-of-range value, etc.) it replies with an "Exception Response": the original function code with bit 7 set to 1, followed by an Exception Code explaining the reason.HardV/F→
- 03Function 0x05 "Write Single Coil" writes a single binary output on a Modbus slave. The ON value is encoded as 0xFF00 and OFF as 0x0000; any other value is invalid.MediumV/F→
- 04Function 0x06 "Write Single Register" writes a single 16-bit Holding Register on a Modbus slave, with both the address and the value encoded on 16 bits each in the request.EasyV/F→
- 05Function 0x08 "Diagnostic" (serial Modbus RTU/ASCII only) is used to test communications and to read internal error counters of a slave through a set of sub-functions (Return Query Data, Restart Communications, Return Bus Message Count, etc.).HardV/F→
Practical
2- 01Modpoll (focus-sw.com) and mbpoll (Linux/macOS) are free command-line tools used to query a Modbus slave from a PC, indispensable for Modbus diagnostics and integration commissioning.MediumV/F→
- 02Modbus (RTU and TCP) has no native security: no authentication, no encryption, no signatures. The accepted good practice is strict OT VLAN isolation, an industrial firewall and no direct internet exposure.HardV/F→
PROFINET
Sourced bankPROFIBUS & PROFINET International
PROFINET
Sourced bankPROFIBUS & PROFINET International
By topic
Architecture
2- 01PROFINET 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).EasyV/F→
- 02A 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.MediumV/F→
Configuration
2- 01In 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.MediumV/F→
- 02'Device Replacement Without Engineering' is a PROFINET function that allows a failed IO Device to be replaced by an unconfigured new unit of the same model, with the PLC then automatically assigning the Name of Station and IP address via LLDP/DCP and downloading the configuration.HardV/F→
Real-time classes
3- 01Which PROFINET real-time class delivers the strictest determinism (cycle <= 31.25 us with jitter <= 1 us), making it suitable for motion-control applications?HardQCM→
- 02A 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).HardV/F→
- 03The 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.MediumV/F→
Topology & cabling
2- 01PROFINET 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.EasyV/F→
- 02The 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.HardV/F→
Diagnostics
3- 01LLDP (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.MediumV/F→
- 02A 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.HardV/F→
- 03PROFINET distinguishes several alarm types: "Process Alarms" (application events raised by the device), "Diagnostic Alarms" (detected hardware anomalies) and "Maintenance Alarms" (preventive maintenance needs).MediumV/F→
Conformance Classes
2- 01Which PROFINET Conformance Class includes support for IRT (Isochronous Real-Time)?HardQCM→
- 02The "Net Load Class" of a PROFINET device certifies its robustness against intense network traffic (flooding, broadcast storm), with three levels (NL Class 1, 2, 3) guaranteeing that the device continues to respond correctly under real-time conditions.HardV/F→
PROFIBUS
Sourced bankPROFIBUS & PROFINET International
PROFIBUS
Sourced bankPROFIBUS & PROFINET International
By topic
Architecture
2- 01Which DP version introduces acyclic services for asynchronous configuration and diagnostics?HardQCM→
- 02PROFIBUS PA is the DP-V1 extension dedicated to process instrumentation, using the MBP (Manchester Bus Powered) physical layer specified in IEC 61158-2 at 31.25 kbps, which carries both power and data on the same twisted pair and is intrinsically safe for hazardous areas.HardV/F→
Migration to PROFINET
2- 01Brownfield migration from PROFIBUS DP to PROFINET typically relies on "proxies" (Siemens IE/PB Link, Hilscher netTAP, ABB gateways) that expose a whole PROFIBUS segment as a single PROFINET device seen by the modern PLC.HardV/F→
- 02PROFIBUS profiles (PROFIsafe, PROFIdrive, PA Profile) are identical between PROFIBUS and PROFINET, which lets you migrate the network infrastructure without having to re-certify the safety, drive or process application functions.MediumV/F→
PROFIBUS PA
2- 01The MBP (Manchester Bus Powered) physical layer of PROFIBUS PA uses Manchester coding at 31.25 kbps on an intrinsically safe twisted pair, supporting up to 32 devices per segment and a maximum length of 1 900 m.HardV/F→
- 02The DP/PA Link coupler bridges a PROFIBUS DP RS-485 backbone to a PROFIBUS PA MBP segment, handling the rate adaptation (1.5 Mbps to 31.25 kbps) and providing the intrinsically safe power supply for the PA segment.HardV/F→
Physical layer
4- 01What is the maximum segment length allowed for PROFIBUS DP at the top bit rate of 12 Mbps?HardQCM→
- 02PROFIBUS RS-485 active terminations (a 390 / 220 / 390 ohm resistor network biased from 5 V) must be present at both ends of the segment and powered; the bus will not work reliably if the terminations are passive or unpowered.HardV/F→
- 03A PROFIBUS RS-485 segment supports up to 32 nodes ("unit loads") without a repeater; beyond that, RS-485 repeaters must be added, and each repeater itself counts as a unit load.MediumV/F→
- 04What is the maximum segment length for a PROFIBUS DP Type A cable at 1.5 Mbps?HardQCM→
GSD files
2- 01A PROFIBUS GSD file (Generic Station Description) is a standardised ASCII file supplied by the device vendor; it contains the device characteristics (vendor, ident_number, supported baud rates, modules, parameters) needed to integrate it in the PLC project.MediumV/F→
- 02A compact PROFIBUS DP slave has an I/O configuration that is frozen at manufacturing time (e.g. a 32-bit encoder, a 4-module pressure transmitter), which simplifies configuration but limits flexibility.MediumV/F→
Diagnostics
2- 01ProfiTrace from Procentec is the reference diagnostic tool for PROFIBUS: it captures telegrams in real time, provides statistical analysis (error rates, cycle times) and embeds an oscilloscope for RS-485 physical signal quality.MediumV/F→
- 02In PROFIBUS DP, device-related diagnostics is an asynchronous vendor-specific message that the slave emits to report internal conditions (temperature alarm, low battery, etc.) which go beyond the standard diagnostic block.HardV/F→
CMVP
Sourced bankEfficiency Valuation Organization
CMVP
Sourced bankEfficiency Valuation Organization
By topic
IPMVP Options
5- 01Which IPMVP option uses field measurement of the key parameter(s) explaining the savings ONLY (with the others estimated) for an isolable ECM?HardQCM→
- 02IPMVP Option C (Whole Facility) is recommended when the expected savings represent more than 10 % of the total building consumption and several ECMs coexist (making individual A/B isolation impractical).MediumV/F→
- 03IPMVP Option D uses a calibrated thermal simulation model (eQUEST, EnergyPlus, IES-VE or equivalent) when baseline or reporting data are unavailable or unreliable, for example in new construction or full system replacements.HardV/F→
- 04The choice of Measurement Boundary in M&V determines which energy flows and explanatory variables must be measured; this boundary often conditions the choice between Options A/B (equipment-level) and Option C (whole facility).MediumV/F→
- 05For new construction, IPMVP Option D builds a 'virtual baseline' via thermal simulation of a reference building (typically meeting current RT/RE requirements but with standard, non-performant equipment) and then compares it to the actual delivered building.HardV/F→
Periods & adjustments
2- 01The baseline period in M&V must be representative of typical operating conditions before the ECM, capturing energy plus explanatory variables (weather, occupancy, production), and typically covers a full 12-month cycle for buildings.MediumV/F→
- 02In IPMVP, routine adjustments correct regular variations (weather, occupancy, production) via regression or factor, while non-routine adjustments (NRA) handle unplanned static changes (added floor area, extra shift, refurbishment) that occur between baseline and reporting periods.HardV/F→
France context
4- 01ISO 50001 (Energy Management System) indirectly cites IPMVP as a good M&V practice in its clause 9.1 (monitoring, measurement, analysis), creating a natural bridge between organisational energy management and the individual CMVP certification.MediumV/F→
- 02RE2020 (in force since 2022) imposes energy (Bbio, Cep, Cep,nr) and carbon (Ic) calculations based on regulatory thermal simulation; to verify that the delivered performance matches design intent, IPMVP Option D (calibrated simulation) is the reference tool.HardV/F→
- 03OPERAT (Observatoire de la Performance Energetique de la Renovation et des Actions Tertiaires) is the official ADEME platform on which every building subject to the Decret Tertiaire must declare its annual consumption, from which compliance with the Crelat/Cabs targets is calculated.MediumV/F→
- 04For tertiary renovation projects in France, several public financing schemes (ADEME Fonds Chaleur, Plan de Relance, BPI Decarbonation loans) require multi-year M&V tracking of realised savings, creating structural demand for CMVP experts.MediumV/F→
Practical
5- 01To verify the savings from a Demand-Controlled Ventilation (DCV) retrofit in a tertiary building, IPMVP Option C with multiple regression including degree-days plus occupancy (measured through presence counters or badges) is typically the most appropriate approach.HardV/F→
- 02Retrofitting a fixed-speed pump to a variable-speed drive (VFD) is typically analysed under IPMVP Option B: measure kW and flow at several operating points before and after, fit a regression model kW = f(flow), and compare at identical operating points.HardV/F→
- 03A fluorescent-to-LED lighting retrofit in offices is typically analysed under IPMVP Option A: meter the kW of a representative sample of the new luminaires, estimate hours of use from a field audit or BMS occupancy data, and compare against the rated draw of the legacy lamps.HardV/F→
- 04HVAC retro-commissioning (re-tuning existing equipment without replacing it, for example optimising AHU sequencing, room setpoints and schedules) is typically evaluated under IPMVP Option C with a 12-month baseline model built from pre-commissioning data.HardV/F→
- 05For a self-consumption photovoltaic (PV) installation, IPMVP proposes a modified approach: savings equal the PV energy consumed on site (self-consumption) plus the revenue from exported surplus, both quantified using two meters (PV production and grid import).HardV/F→
DALI-2
Sourced bankDALI Alliance
DALI-2
Sourced bankDALI Alliance
By topic
Architecture
2- 01DALI-2 (IEC 62386 Edition 2, 2014+) is the major evolution of DALI v1, adding native support for input devices (sensors, push-buttons) directly on the DALI bus itself, together with a product certification programme administered by the DALI Alliance (DiiA).MediumV/F→
- 02The DALI bus uses a polarity-free twisted pair (no + / - orientation), with Manchester coding at 1 200 baud over a nominal 22.5 V DC supply, and is allowed to share the same multi-core cable as the 230 V mains feeding the luminaires.MediumV/F→
Emergency DT1
3- 01A DALI DT1 Function Test simulates a 30-second mains outage to verify that the emergency luminaire switches over to battery; the result (OK / Battery Fault / Lamp Fault) is reported back to the controller for an EN 50172-compliant audit trail.HardV/F→
- 02The DALI DT1 Duration Test verifies the battery autonomy of an emergency luminaire by simulating a long mains outage (typically 1 h or 3 h depending on the EN 50172 category); a failure indicates an end-of-life or faulty battery that requires replacement.HardV/F→
- 03The DALI DT1 'Inhibit' (or 'Rest Mode') temporarily disables an emergency luminaire during planned building maintenance, avoiding spurious tests during the intervention; the gear returns automatically to normal mode after a timeout.MediumV/F→
Standards
2- 01The DALI-2 standard is codified as IEC 62386, split into several parts: 62386-101 (general requirements / system), 62386-102 (control gear), 62386-103 (control devices), 62386-2xx (lamps and device types) and 62386-3xx (input devices).MediumV/F→
- 02DiiA (DALI Alliance) certifies DALI-2 products in accredited test laboratories and publishes a public Approved Products List on dali-alliance.org, which lets integrators verify the conformance of a product before purchase.MediumV/F→
Devices
2- 01DALI-2 LED control gear is identified by a Device Type (DT): DT6 covers single-intensity LED, DT8 covers colour control (including Tunable White, RGB, RGBW, XY chromaticity and Tc in Kelvin), and DT0 covers fluorescent lamps (legacy).HardV/F→
- 02Self-contained emergency luminaires (DT1) under DALI-2 support standardised commands for the monthly function tests and annual duration tests required by EN 50172, and these tests can be automated from a central DALI-2 controller.HardV/F→
KNX-DALI integration
3- 01A KNX/DALI gateway can drive up to 64 control gear on one DALI bus from KNX commands, exposing the gear as KNX Group Objects (DPT 1.001 on/off, DPT 5.001 dimming, DPT 232.600 RGB, DPT 17.001 scene).MediumV/F→
- 02The usual KNX-to-DALI mapping is: DPT 1.001 to on/off (Direct Arc Power 0/254), DPT 5.001 to linear dimming converted to log by the gear, DPT 232.600 to DT8 RGB, and DPT 17.001 to Recall Scene (DPT 17.001 values 0-63 mapped to DALI scenes 0-15 modulo 16).MediumV/F→
- 03A modern KNX/DALI gateway can schedule and trigger function tests and duration tests on DT1 emergency luminaires per EN 50172, and report the results to the KNX supervisor via Group Objects of type DPT 1.001 (test OK) or DPT 232 (multi-status).HardV/F→
Memory Banks
3- 01The standardised DALI-2 Memory Bank 0 (MB0) contains the gear's identification data: Vendor ID (assigned by DiiA), GTIN (Global Trade Item Number), hardware version, firmware version and serial number.MediumV/F→
- 02The standardised DALI Memory Bank 1 (MB1) stores lamp operation data: cumulative operating hours, switching cycles, maximum temperature, supporting lifecycle tracking and predictive maintenance.MediumV/F→
- 03The D4i Memory Banks (MB201-MB206) extend DALI-2 with smart-city lifecycle data: MB201 luminaire diagnostic, MB202 asset info, MB203/204 energy data (cumulative kWh and instantaneous W), MB205 features and MB206 control-gear health.HardV/F→
OPC UA
Sourced bankOPC Foundation
OPC UA
Sourced bankOPC Foundation
By topic
Architecture
2- 01OPC UA supports two communication patterns: Client/Server (the classic Request/Response model) and Pub/Sub (publish/subscribe over MQTT or UDP multicast/unicast), the latter introduced in version 1.04 to address Industrie 4.0 use cases.MediumV/F→
- 02The OPC UA Address Space is a hierarchical structure of Nodes linked by typed References (HasComponent, HasProperty, HasTypeDefinition, etc.), exposed as a graph that clients can walk through the Browse service.MediumV/F→
Vendor implementations
2- 01Siemens S7-1500 (and S7-1200 V4.5+) PLCs embed a native OPC UA server that can be configured directly from TIA Portal: expose or restrict variables, set Security Mode and Policy, manage certificates, all without any additional hardware.MediumV/F→
- 02Ignition (Inductive Automation) is a modern SCADA/MES platform built around native OPC UA: it ships one integrated OPC UA Server plus drivers for 60+ protocols (BACnet, Modbus, KNX via gateway, Siemens S7, etc.), a web-based HMI and an MQTT IIoT Pub/Sub engine.MediumV/F→
Discovery
2- 01An OPC UA Local Discovery Server (LDS) is a service that maintains a registry of the OPC UA servers available on the local network; clients can query it to find servers dynamically without knowing their URLs in advance.HardV/F→
- 02An OPC UA Global Discovery Server (GDS) manages a cross-LDS registry plus a Certificate Authority (CA) that issues client and server certificates across a multi-site infrastructure, dramatically simplifying OPC UA PKI management.HardV/F→
Services
2- 01The main OPC UA Service Sets are: Discovery, SecureChannel, Session, NodeManagement, View, Query, Attribute (Read/Write), MonitoredItem, Subscription, and Method (Call).MediumV/F→
- 02An OPC UA Subscription groups several MonitoredItems and publishes value changes periodically (PublishingInterval typically 100-1000 ms); the server keeps a buffer of unacknowledged notifications for reliability.HardV/F→
Security
3- 01Which Security Modes does an OPC UA SecureChannel support per the standard?HardQCM→
- 02OPC UA uses X.509 certificates to authenticate applications (both client and server): each application holds its own certificate, and trust is established mutually through the exchange that happens during the SecureChannel handshake.HardV/F→
- 03OPC UA separates Application authentication (the client/server X.509 certificate) from User authentication (the actual end-user login), which can be Anonymous, Username/Password, or User Certificate.MediumV/F→
Tools
2- 01UaExpert (Unified Automation) is the reference free OPC UA client for Windows, Linux and macOS: it browses the Address Space, reads and writes values, subscribes to changes, calls Methods and manages certificates, and is an indispensable tool for any OPC UA integrator.MediumV/F→
- 02node-opcua is the most popular Node.js (JavaScript) OPC UA implementation, used for fast prototyping, audit scripts and Web/MQTT/REST-to-OPC-UA integrations, and it is embedded in Node-RED and in many IoT projects.MediumV/F→
Pub/Sub
2- 01OPC UA Pub/Sub supports several transports: UDP multicast (lowest latency, machine-to-machine), MQTT (cloud-friendly via broker) and AMQP (enterprise messaging), making it adaptable to a wide range of use cases.HardV/F→
- 02OPC UA Pub/Sub supports two encodings: Binary (compact and fast, about 30% of the payload size of JSON) and JSON (human-readable, debug-friendly, easy to integrate with web and REST stacks). The choice depends on the performance versus interoperability trade-off.HardV/F→
EnOcean
Sourced bankEnOcean Alliance
EnOcean
Sourced bankEnOcean Alliance
By topic
Architecture
2- 01EnOcean is best known for its battery-less devices: energy is harvested from a piezo-electric element (mechanical push-button), a solar cell (sensors with a small photovoltaic panel) or a Peltier element (thermal gradient), eliminating battery maintenance over a 10 to 20 year service life.MediumV/F→
- 02Which EnOcean radio frequencies are used in Europe, North America and Japan respectively?EasyQCM→
Use cases
2- 01Modern hotels use EnOcean for room occupancy detection (door handles, door contacts, presence sensors) wired through to the PMS (Property Management System) to optimise HVAC, switching to Eco mode when the room is empty and to Comfort mode on guest arrival.MediumV/F→
- 02For a residential smart-home retrofit project (without touching the existing wiring), EnOcean is the dominant choice: battery-less wireless push-buttons replace conventional switches, ambient sensors are added on top, and integration runs through an Apple HomeKit or Matter gateway.MediumV/F→
EEP
3- 01The EEP (EnOcean Equipment Profile) identifies each device type by a RORG-FUNC-TYPE triplet (e.g. F6-02-01 = 2-channel Rocker push-button), enabling a receiver to decode the telegram correctly without any manual configuration.HardV/F→
- 02The most common EnOcean RORG values are RPS (F6, Repeated Switch Telegram, push-buttons), 1BS (D5, 1-Byte Sensor, magnetic contacts), 4BS (A5, 4-Byte Sensor, temperature / CO2 / lux sensors) and VLD (D2, Variable Length Data, modern multi-function devices).HardV/F→
- 03In the EnOcean Teach-In process, the transmitting device sends a special telegram containing its EEP and Device ID; the receiver memorises this information so it can decode later telegrams correctly and bind the sender to a specific action.MediumV/F→
Security
2- 01EnOcean Secure uses a rolling code (an incremental counter) together with a CMAC (Cipher-based MAC built on AES-128) to authenticate every telegram and block replay attacks, which is critical for security-grade applications such as alarms and wireless locks.HardV/F→
- 02ePIRE (EnOcean Profile for Initial Resync Exchange) is the standardised protocol for secure pairing during Teach-In: it covers the generation and distribution of the shared AES key between a Secure-capable transmitter and receiver.HardV/F→
KNX integration
2- 01A KNX / EnOcean gateway (Theben EnOcean Gateway, Weinzierl EnOcean Module, etc.) allows EnOcean devices to be integrated into a KNX project: each EnOcean sender (button or sensor) is mapped to a KNX Group Address.MediumV/F→
- 02EnOcean is particularly well suited to the retrofit of existing buildings: sensors and buttons can be added without pulling cable or fitting batteries, with a 20+ year service life, making it ideal for heritage buildings or sites that are difficult to rewire.MediumV/F→
Tools
2- 01DolphinView (EnOcean Alliance, free of charge) is the reference tool for EnOcean developers and integrators: it sniffs radio telegrams, decodes EEPs, simulates devices and supports debugging during installation.MediumV/F→
- 02EnOcean USB dongles (USB 300, USB 400, USB 500) let a PC or a Raspberry Pi act as an EnOcean gateway: standard USB-to-serial drivers plus libraries in Python or Node.js (enocean-python, node-enocean) enable custom integrations.MediumV/F→
Matter
Sourced bankConnectivity Standards Alliance
Matter
Sourced bankConnectivity Standards Alliance
By topic
Architecture
3- 01Matter (formerly CHIP, Connected Home over IP) is a residential IoT interoperability standard maintained by the CSA (Connectivity Standards Alliance), letting a single device be controlled simultaneously by Apple Home, Google Home, Amazon Alexa and Samsung SmartThings.EasyV/F→
- 02Which transport networks are natively supported by production Matter devices in 2026?MediumQCM→
- 03Thread is a low-power IPv6 mesh protocol built on IEEE 802.15.4 (the same physical layer as Zigbee but a different upper stack), used by Matter for battery-powered devices such as sensors and locks where battery life ranges from several months to several years.HardV/F→
Limitations
2- 01Matter 1.x still has clear gaps compared with proprietary ecosystems: no native camera support until 1.4, limited cross-ecosystem cloud sync, basic power management for battery devices and audio/video streaming still on the roadmap.MediumV/F→
- 02Matter is targeted exclusively at residential and small-commercial deployments: its consumer-grade commissioning experience and device catalogue are not suited to the tertiary or industrial requirements where KNX, BACnet and Modbus remain the leaders.MediumV/F→
Commissioning
2- 01Commissioning a Matter device is typically done by scanning a QR code (printed on the device or its packaging) with a smartphone app such as Apple Home, Google Home or Alexa; the QR carries the Setup PIN and Discriminator needed to authenticate the pairing.EasyV/F→
- 02Matter defines two secure-channel modes: PASE (Password Authenticated Session Establishment), used during commissioning with the Setup PIN as a shared secret, and CASE (Certificate Authenticated Session Establishment), used post-commissioning with mutual X.509 certificates.HardV/F→
Multi-admin
2- 01A Matter device can belong to several Fabrics at the same time (five by default), one Fabric per ecosystem (Apple, Google, Amazon, etc.), allowing a single user to control the device interchangeably from different apps.HardV/F→
- 02Each Matter Fabric is cryptographically isolated from the others: Apple Home cannot see the automations configured in Google Home on the same device, which guarantees confidentiality between competing ecosystems.HardV/F→
Device types
2- 01Matter Spec 1.0 already supports the core residential device types: OnOff Light, Dimmable Light, Color Temperature Light, Extended Color Light (RGB), Smart Plug, Door Lock, Contact Sensor, Motion Sensor, Window Covering, Thermostat and more.MediumV/F→
- 02A Matter device implements several Clusters (functional building blocks) according to its device type: OnOff Cluster for switching, Level Control for dimming, Color Control for RGB, and so on; each Cluster exposes Attributes for state readout and Commands for actions.HardV/F→
Bridge
2- 01The Matter Bridge pattern lets legacy devices (Zigbee, Z-Wave, KNX, EnOcean, proprietary protocols) be exposed as virtual Matter devices to a Matter ecosystem, by mapping their native features onto Matter Clusters.HardV/F→
- 02KNX-to-Matter bridges are emerging in 2026 (1Home, BAB Technologie, BootCloud): they expose KNX Group Objects as Matter devices (OnOff Light, Dimmable Light, etc.), letting residential KNX users add consumer Matter products without extra complexity.HardV/F→
Practical
2- 01Running Matter devices over Thread (battery sensors, locks) requires at least one Thread Border Router in the home: Apple TV 4K (3rd gen and later), Apple HomePod mini or HomePod 2, Google Nest Hub (2nd gen and later), Amazon Echo (4th gen and later) or Samsung SmartThings Hub.HardV/F→
- 02Matter Wi-Fi devices typically connect on the 2.4 GHz band (lower power consumption and longer range than 5 GHz), which means the home router must either expose a dedicated 2.4 GHz SSID or use a combined SSID with band steering disabled.MediumV/F→
Open source
2- 01The Matter SDK is fully open source (Apache 2.0) on GitHub (project-chip/connectedhomeip) with more than one hundred active contributors, which lets OEMs ship Matter devices quickly and lets hobbyists and Home Assistant integrate Matter directly.MediumV/F→
- 02Home Assistant has integrated Matter natively since 2023 through its Matter Server add-on, letting Home Assistant users commission Matter devices directly and act as a controller on equal footing with Apple Home or Google Home.MediumV/F→
LoRaWAN
Sourced bankLoRa Alliance
LoRaWAN
Sourced bankLoRa Alliance
By topic
Architecture
3- 01An important distinction must be made: "LoRa" is the physical-layer radio modulation (CSS, Chirp Spread Spectrum, proprietary to Semtech), whereas "LoRaWAN" is the MAC-layer protocol and network architecture (an open standard from the LoRa Alliance) built on top of LoRa.MediumV/F→
- 02A LoRaWAN architecture comprises four entities: End Devices (LoRa sensors and actuators), Gateways (bidirectional radio relays), a Network Server (which centralises traffic and handles ADR and security) and an Application Server (which carries the business logic and exposes the data to end users).MediumV/F→
- 03LoRaWAN uses a "star-of-stars" topology: each end device transmits unidirectionally toward ALL in-range gateways, the gateways forward the packet to the Network Server, which deduplicates the copies; there is no mesh between end devices.MediumV/F→
Tools
2- 01The Things Network (TTN) is a free community LoRaWAN platform (community gateways plus a hosted Network Server) widely used for development, prototyping and maker-friendly deployments, with a web console and MQTT/HTTP SDKs for application integration.MediumV/F→
- 02ChirpStack is the most popular open-source LoRaWAN Network Server and Application Server (MIT licence) for private deployments, supporting LoRaWAN 1.0.x and 1.1, multi-tenant operation and a web UI plus gRPC/REST APIs.MediumV/F→
Frequencies
2- 01Which frequency band is used by LoRaWAN in Europe?MediumQCM→
- 02In Europe (EU868), the ETSI EN 300 220 regulation typically limits the duty cycle to 1 % per hour on the main sub-band, which caps the number of frames an end device can transmit (from a few dozen to more than two hundred per hour depending on the spreading factor).HardV/F→
Classes
2- 01Which LoRaWAN class offers the lowest latency for downlink messages (Network Server to end device) but also the highest energy consumption?MediumQCM→
- 02More than 90 % of LoRaWAN end devices in the field run in Class A: battery-powered sensors (water meters, GPS trackers, weather stations, level probes), periodic uplinks (every 10 minutes to 24 hours depending on the use case) and 5-10 years of autonomy on an AA or lithium cell.MediumV/F→
Activation
2- 01Which LoRaWAN activation method is generally recommended for production deployments?HardQCM→
- 02An OTAA LoRaWAN end device is identified by: a DevEUI (a 64-bit device-unique identifier, similar in spirit to a MAC address), an AppEUI/JoinEUI (a 64-bit application owner identifier) and an AppKey (a 128-bit pre-shared secret used for the OTAA Join procedure).HardV/F→
Network providers
2- 01As of 2026, the main public LoRaWAN operators in France are: Orange Live Objects (near-nationwide coverage), Bouygues Objenious (in sunset), Helium Network (community-driven) and Loriot (Swiss-based commercial Network Server vendor, not a public carrier). In addition, many deployments are run on private networks (dedicated infrastructure).MediumV/F→
- 02For critical IoT deployments (smart city, industrial sites, fleet asset tracking), private LoRaWAN networks are often preferred over public operators: full infrastructure control, contractual SLA, stronger security and no commercial dependency on a third-party operator.MediumV/F→
Use cases
2- 01Typical LoRaWAN smart-city use cases include: smart water meters, parking-bay occupancy sensors, fill-level sensors for waste bins, public-lighting telemonitoring, air-quality stations, EV charger monitoring (status and energy readings — not the OCPP charge-control protocol) and flood alerts — a typical LoRaWAN sensor costs between EUR 30 and EUR 150.MediumV/F→
- 02In building retrofits, LoRaWAN competes with EnOcean for energy sub-metering and wireless monitoring (temperature, CO2, presence): long range (one gateway covers a large building), 5-10 years of battery life on the sensors, but higher latency (Class A).MediumV/F→
Standards
2- 01The LoRa Alliance is the non-profit organisation that maintains the LoRaWAN standard (public specification, product certification programme and operator programme), with more than 500 members worldwide, including the major silicon vendors, public operators and device makers.EasyV/F→
- 02The major LoRaWAN versions are: 1.0 (2015), 1.0.1, 1.0.2 and 1.0.3 (minor revisions), 1.0.4 (2020, with improved security) and 1.1 (2017, with significant changes — four session keys: FNwkSIntKey, SNwkSIntKey and NwkSEncKey on the network side, plus AppSKey on the application side — and a dual-security model).MediumV/F→
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