Bosch DS939 Panoramic Ceiling-Mount PIR Motion Detector is a commercial-grade, 360-degree passive infrared (PIR) intrusion detector designed to monitor large indoor areas from an overhead mounting position. Its panoramic detection pattern helps secure open floor plans, warehouses, retail spaces, offices, corridors, and other locations where conventional wall-mounted motion detectors may leave gaps or be obstructed by shelving, equipment, or interior partitions.

The DS939 uses three individually adjustable PIR optical sections to tailor its detection pattern to the room. It combines Bosch First Step Processing (FSP) and dynamic temperature compensation to detect human movement promptly while reducing nuisance alarms. For UL/ULC applications, Bosch specifies 360° coverage up to 46 ft (14 m) in diameter when mounted up to 20 ft (6.1 m) high. Actual coverage depends on ceiling height, optical adjustment, mounting conditions, and the applicable approval standard.

Key Features & Benefits

• 360-degree panoramic coverage: Monitors floor areas surrounding the detector from a central ceiling location rather than a single wall-facing direction.
• Up to 46-ft coverage diameter for UL/ULC: Up to 23-ft radius with approved installation and mounting conditions.
• Three adjustable PIR sections: Independent optical adjustments allow installers to focus coverage on specific zones or room geometry.
• First Step Processing (FSP): Intelligent PIR signal analysis supports fast detection of moving human targets while limiting unwanted alarms.
• Dynamic temperature compensation: Maintains effective detection as ambient temperature changes.
• Coverage masking kit included: Supplied masking pieces allow exclusion of selected sectors of the 360° pattern to reduce monitoring of unwanted areas.
• LED walk-test indication: High-efficiency LED and light-pipe design make the detector's activation indication easy to see from different viewing angles.
• Remote LED control and alarm memory: Supports remote LED testing and alarm-memory functions during commissioning and service.
• Form C alarm relay: Provides a dry-contact alarm output for a compatible intrusion alarm control panel.
• Cover/base tamper protection: Normally closed tamper supervision helps identify unauthorized removal or opening.
• Hinged chassis and mounting base: Facilitates wiring, configuration, and service access during installation.
• 9–15 VDC operation: Low-voltage wired detector suited to compatible commercial intrusion alarm systems.

Technical Specifications

Commercial Applications

Designed for intrusion alarm monitoring in warehouses, commercial office interiors, retail sales floors, healthcare facilities, storage areas, schools, and buildings with high ceilings or significant floor-level obstacles. Overhead PIR detection is useful where a central mounting position offers more complete monitoring than a wall-mounted detector. The DS939 requires a compatible wired intrusion alarm panel and low-voltage power source.

Ordering & Installation Notes

Verify that the Bosch DS939 is appropriate for your alarm system, ceiling height, coverage diameter, power supply, wiring requirements, and applicable approval standard before ordering. Mounting height and pattern adjustments affect actual coverage. Avoid placement near moving fans, rapid temperature changes, and other potential PIR interference sources. Confirm alarm and tamper relay ratings before connecting the detector to a control panel. Follow the manufacturer's installation manual and local security/electrical codes.

Important: The DS939 is a ceiling-mounted intrusion motion detector, not a dedicated request-to-exit (REX) door release sensor. It does not include a complete alarm control panel, power supply, electric lock, or door release controller.

Commercial Door Worx supplies Bosch security motion detectors, access-control equipment, electronic security components, and commercial door hardware for installers, facility maintenance teams, and commercial building owners.