ABAT Sensors, Detectors & Detection Devices Flashcards
6 cards from real ABAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 ABAT Sensors, Detectors & Detection Devices flashcards as text
Active infrared beam detectors generate an alarm when the invisible beam between the transmitter and receiver is interrupted. What is one major limitation of this detector type?
Answer: They require a direct line of sight and can be defeated by slow low-crawl intrusion
Active IR beam detectors require unobstructed line of sight and can potentially be defeated by an intruder moving slowly below the beam height, which is why they are often stacked in multiple beams or combined with other sensor types.
What does 'pet immunity' in a PIR motion detector typically mean?
Answer: The detector ignores all motion below a programmable weight threshold, typically up to 40–80 lbs
Pet-immune PIR detectors use downward-angled lens patterns and sensitivity adjustments to ignore heat signatures below a certain mass/height threshold (commonly up to 40–80 lbs), allowing animals to move freely without triggering alarms.
A seismic or vibration sensor is best suited for protecting which type of asset?
Answer: Vaults, safes, and ATMs against physical attack
Seismic detectors sense the low-frequency vibrations produced by drilling, cutting, or impact attacks on hard surfaces, making them ideal for protecting vaults, safes, and ATMs from physical attacks.
What type of sensor is best used to detect intruders crossing an outdoor perimeter such as a fence line?
Answer: Microwave fence disturbance sensor or electrostatic sensor
Microwave fence disturbance sensors or electrostatic field sensors are specifically designed to detect climbing, cutting, or lifting of fence panels along an outdoor perimeter.
What causes 'range creep' in microwave motion detectors?
Answer: Microwave energy passing through walls and detecting motion in adjacent rooms or outside the building
Microwave signals penetrate non-metallic walls and materials, so a microwave detector can detect motion in unintended areas like adjacent rooms, stairwells, or even outside the building.
When installing a PIR detector in a room with large windows facing south, what environmental concern must be addressed?
Answer: Direct sunlight or reflected heat from HVAC vents can cause false alarms
PIR detectors sense changes in infrared heat; direct sunlight, clouds moving across the sun, or HVAC heat drafts can create sudden temperature changes that mimic a moving body and trigger false alarms.