Silent Knight’s addressable detection and module ecosystem, built around the SD500 protocol, offers fire alarm installers and service technicians a reliable, flexible platform for commercial life-safety systems. This guide covers the addressable detector and module lineup, how to select the right device for each application, and basic wiring considerations for SD500 loop devices.
Silent Knight Addressable Detector Types
All SD500-protocol detectors provide individual point addressability, real-time analog values, and full NFPA 72 compliance. Each detector reports its status and sensitivity reading directly to the panel, enabling predictive maintenance and reducing unwanted alarms.
SK-PHOTO — Photoelectric Smoke Detector
The SK-PHOTO uses light-scattering technology to detect slow, smoldering fires characteristic of overheated wiring, upholstery, and wood-based materials. It is the standard detector choice for:
- Office corridors and open-plan spaces
- Storage rooms and warehouses
- Hotel and dormitory common areas
- Any occupancy where smoldering fires are the primary hazard
SK-HEAT — Heat Detector
The SK-HEAT addresses environments where smoke detectors produce chronic false alarms. It provides both fixed-temperature response (typically 135°F) and rate-of-rise detection. Recommended locations include:
- Commercial kitchens and food service areas
- Boiler rooms and mechanical spaces
- Dusty or dirty industrial environments
- Unheated attic and crawl spaces
SK-CO — Carbon Monoxide Detector
The SK-CO integrates carbon monoxide monitoring directly onto the SD500 addressable loop, eliminating the need for a separate CO system. It is required by code in many occupancies where fuel-burning appliances are present. The SK-CO reports CO levels in ppm to the panel, allowing alarm and supervisory thresholds to be set independently.
SD500 Addressable Modules
Silent Knight’s module lineup extends the addressable loop to conventional devices, control circuits, and remote signaling applications.
Monitor Input Modules (MIM / AIM)
The SD500-MIM (Mini Input Module) and SD500-AIM (Addressable Input Module) supervise Class B or Class A conventional initiating device circuits. Common applications include:
- Monitoring conventional pull stations
- Supervising sprinkler tamper and flow switches
- Monitoring duct smoke detectors wired conventionally
- Connecting legacy 2-wire smoke detector zones to an addressable loop
The AIM supports a full 2-wire IDC; the MIM is a compact alternative for single-device or space-limited applications.
Control Interface Module (CIM / ARM)
The SD500-ARM (Addressable Relay Module) and SD500-CIM (Control Interface Module) provide supervised relay outputs for controlling:
- HVAC shutdown and air-handling unit control
- Door holder and door release circuits
- Elevator recall and fire shutter control
- External annunciator and graphic panel inputs
Wiring SD500 Loop Devices
SD500 devices use a standard 2-wire Class B (Style B) or 4-wire Class A (Style 6/7) loop configuration. Key wiring guidelines:
- Wire gauge: 18 AWG twisted pair is standard; 14-16 AWG may be used for longer runs.
- Loop resistance: Total loop resistance should not exceed the panel’s published maximum (consult the SK-5208/5212/5496 installation manual).
- Addressing: Each device is set to a unique address (1–254 per loop) via rotary switches or programmer.
- End-of-line: Class B loops require an EOLR at the last device; Class A loops return to the panel on a separate conductor pair.
Find Your Silent Knight Detector or Module
Life Safety Consultants carries new and reconditioned SD500 detectors and modules for immediate shipment. Whether you need a single replacement unit or are restocking a service van, we have the inventory and expertise to support your Silent Knight system.
Shop our full selection of Silent Knight fire alarm replacement parts or call us at 888-557-0558 for application support.
