hard DALI-2 exam questions
DALI-2 Knowledge mock exam questions selected at hard level. Ideal for preparing for the discriminating questions you'll see on exam day.
Hard level questions
Q01
Self-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.TrueFalse2. Devices· Typ 1 Notbeleuchtung· HardCorrect answerTrueLearning tipDT1 defines an emergency-specific command set: Function Test (short test, around 30 s, to verify battery-driven turn-on); Duration Test (1 to 3 hours depending on category, to verify autonomy); Inhibit / Re-light for maintenance windows; and Status reporting (battery OK, lamp fault, replacement required). Together they replace the manual walk-round inspection with automated tests and a centralised log, producing substantial savings in buildings with 50+ emergency luminaires.
Q02
DALI-2 supports several application controllers active on the same bus (multi-master), with an arbitration mechanism that prevents conflicts when two controllers try to command the same control gear at the same time.TrueFalse4. Application Controllers· Multi-Master· HardCorrect answerTrueLearning tipMulti-master operation is a DALI-2 addition: DALI v1 was strictly single-master (one controller per bus), whereas DALI-2 allows multiple controllers with CSMA/CA arbitration. A typical use case is running a dedicated application controller for everyday control alongside a KNX/DALI gateway for supervision on the same bus, without conflicts. Arbitration is based on collision detection and a random back-off delay, enabling more flexible architectures.
Q03
A 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.TrueFalse13. Emergency DT1· Function Test· HardCorrect answerTrueLearning tipThe Function Test is the standardised monthly test required by EN 50172: it lasts about 30 s (long enough to verify turn-on), opens the internal mains relay so the battery takes over, and checks that the LED lights up at or above the minimum luminance threshold. Results are stored in MB202 (the Emergency Memory Bank) with date and result code, and are queryable from a central controller. Automation produces a strong ROI, typically saving 80 percent of the manual inspection effort.
Q04
The 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.TrueFalse13. Emergency DT1· Duration Test· HardCorrect answerTrueLearning tipThe Duration Test is the annual test required by EN 50172. Emergency luminaire categories under EN 50172 mandate a minimum 1 h autonomy (categories 1, 2 and 3), with a nominal autonomy generally of 1 h, going up to 3 h for specific installations. The test must be scheduled outside of occupancy hours (night or weekend). A failure means the battery is at end of life and must be replaced — typical battery life is 4-7 years.
Q05
In a mixed KNX-DALI architecture, a DALI-2 presence sensor (sitting on the DALI bus) can drive only the room's DALI control gear, while a separate KNX presence sensor handles room-level commands (HVAC, blinds).TrueFalse16. Integration· Mehrfachnutzung KNX-/DALI-Sensorik· HardCorrect answerTrueLearning tipA common and efficient hybrid pattern dedicates one sensor per natural function: a DALI-2 presence sensor in the room drives the local control gear directly (without traversing KNX, for faster reaction), and a complementary KNX sensor drives HVAC and blinds via the building backbone. Lighting reacts within about 100 ms on DALI, while a 2 s KNX-driven HVAC reaction is acceptable. The design has to be coordinated with the lighting architect.