CLC Lighting Controls & Technologies 2 — Questions and Answers
Question 1: Which DALI command group allows a lighting controller to broadcast a single command to all ballasts on the bus simultaneously?
- Broadcast address (255) (Correct answer)
- Group address 0
- Scene address 16
- Short address 0
Correct answer: Broadcast address (255)
In DALI, the broadcast address (255) sends a command to every device on the bus without addressing individual short addresses.
Question 2: A 0–10V dimming control signal at 0V typically results in what lamp behavior?
- Full off or minimum dim level per ballast specification (Correct answer)
- Full brightness
- 50% light output
- Rapid cycling on and off
Correct answer: Full off or minimum dim level per ballast specification
A 0V signal on a 0–10V system drives the ballast to its minimum dim level or full off, depending on manufacturer implementation.
Question 3: In a Lutron RadioRA 2 wireless system, what is the maximum number of devices supported per system?
- 200 devices (Correct answer)
- 100 devices
- 500 devices
- 50 devices
Correct answer: 200 devices
Lutron RadioRA 2 supports up to 200 devices per system, making it suitable for mid-sized residential and small commercial applications.
Question 4: Which sensor technology is MOST reliable for detecting fine motor movements such as typing at a desk?
- Ultrasonic
- Passive infrared (PIR)
- Microwave
- Dual-technology combining PIR and ultrasonic (Correct answer)
Correct answer: Dual-technology combining PIR and ultrasonic
Dual-technology sensors combining PIR and ultrasonic are most reliable for fine motion, as PIR alone can miss small movements while ultrasonic alone may cause false triggers.
Question 5: What is the primary advantage of a networked lighting control system over a standalone relay-based system in a large commercial building?
- Centralized monitoring, scheduling, and energy reporting across all zones (Correct answer)
- Lower initial hardware cost
- Simpler wiring topology
- No need for occupancy sensors
Correct answer: Centralized monitoring, scheduling, and energy reporting across all zones
Networked systems enable facility managers to monitor energy use, adjust schedules, and diagnose faults from a single interface across the entire building.
Question 6: In DMX512 protocol, how many individual control channels does a single DMX universe support?
- 512 (Correct answer)
- 256
- 1024
- 128
Correct answer: 512
DMX512 provides exactly 512 channels per universe, each carrying an 8-bit value (0–255) that can control intensity, color, or other fixture parameters.
Question 7: A daylight harvesting system in a perimeter office zone fails to dim luminaires even though the photosensor reads high lux. What is the MOST likely cause?
- The photosensor setpoint is set higher than the measured lux value (Correct answer)
- The luminaires are incompatible with dimming
- The occupancy sensor has timed out
- The emergency circuit is overriding normal control
Correct answer: The photosensor setpoint is set higher than the measured lux value
If the controller's target setpoint is above the actual measured lux, the system never activates dimming because it perceives insufficient light.
CLC Lighting Controls & Technologies 2
Which DALI command group allows a lighting controller to broadcast a single command to all ballasts on the bus simultaneously?